ECE Department

ELECTRONICS AND COMMUNICATION ENGINEERING - EC1006-MEDICAL ELECTRONICS 2010

2011-01-02T07:42:00.000-08:00

BE/B.Tech DEGREE EXAMINATION, NOVEMBER/DECEMBER 2010.

Sixth Semester

ELECTRONICS AND COMMUNICATION ENGINEERING

EC1006-MEDICAL ELECTRONICS

(Regulation 2004)

Time:3Hrs Max:100

Answer all questions

PART-A-(10x2=20)

1. 1.What are the different types of bio potential electrodes?

2. 2.Mention the normal amplitude and frequency of EMG signal.

3. 3.Mention the applications of auto analyzer.

4. 4.What do you understand by electrophoresis?

5. 5.What is a radio-pill?

6. 6.Name the instruments needed for bio-telemetry system.

7.List out the various radio isotopes used in diagnosis

8. Brief about the effectiveness of radio isotopes

9. 9.How do electrical hazards occur due to medical equipments?

1 10.What are the electrical safety methods used in hospitals?

PART-B-(5x16=80)

1111(a)Describe with simple diagrams, the various lead systems used while recording ECG signals.

(b)With block diagram explain the EEG recording system.

12 12(a)With neat diagram, describe an ultra sonic blood flow meter.

(b)Explain how the respiratory measurement is carried out using respiratory apparatus.

1313 (a)With a suitable diagram, explain the operation of any one type of cardiac pacemaker.

(b)With a suitable block diagram, explain a multi-channel bio-telemetry.

1414 (a)Explain the properties and importance of ionizing radiation in detail.

(b)Explain radiation therapy and its related equipments.

15 (a)With a suitable schematic diagram, explain the endoscopy unit.

(b)Describe the principles involved in the following

(i)Microwave diathermy .

(ii)Ultra sonic diathermy.

--------------------------------------------------------

TQM:Electronics & Communication Engineering 7th semester notes

2010-11-10T23:43:00.001-08:00

SUBJECT: MG 1401-TOTAL QUALITY MANAGEMENT

SET-3

PART-A

1] Define quality.

A] Fitness for intended use; Conformance to specifications; Meeting or exceeding customer expectations, etc.

2] What do you understand by quality statement?

A] It includes the vision, mission, and quality policy statements. They are part of the strategic planning process.

3] What is cross functional team?

A] It is a team comprising of members from different functional area such as engineering, marketing, accounting, production, quality, human resources, etc. This type of team breaks down functional area boundaries.

4] Expand 5S.

A] Seiri, Seiton, Seiso, Seiketsu, and Shitsuke.

5] List out various measures of dispersion in SPC.

A] Range, Standard Deviation, and Variance.

6] What is Six Sigma?

A] Six sigma is a rigorous concept of applying SPC to control defects in products/processes to 3.4 parts per million (ppm) as against 0.27% (2,700ppm) defects in the traditional three sigma approach. Hence the application of six sigma concept means controlling variations and thereby defects closer to the level of zero defects.

7] What is Kaizen?

A] Kaizen is a Japanese term which means ‘continuous improvement’. It is based on the belief that virtually any aspect of an operation or process can be improved and the people most closely associated with it are in the best position to identify the changes to be made.

8] What is Taguchi Quality Loss Function?

A] Taguchi worked in terms of quality loss rather than quality. He used loss function to measure quality. The loss function is defined ad “loss imparted to society by a product during its life cycle”, i.e. the costs incurred in the production process as well as the costs encountered during use by the customer.

9] What are the objectives of TPM?

A] Maintaining equipment for life; maintaining and improving equipment capacity; using support from all areas of operation; encouraging inputs from all employees.

10] What is the need for quality systems in an organization?

A] They promote the growth of international trade by facilitating harmonious interactions between suppliers and customers located in diverse locations globally.

PART-B

11[a] List out the barriers to TQM implementation.

A] Explain the various likely barriers to effective TQM implementation such as Lack of management commitment, Inability to change organizational culture, etc.

11[b] Discuss the dimensions of quality with examples.

A] Discuss the various dimensions of product quality such as Performance, Features, Usability, etc. and the various dimensions of service quality such as Time, Timeliness, Completeness, etc. supported by appropriate examples.

12[a] Explain the actions that an organization should take to handle customer complaints.

A] Explain the characteristics of dissatisfied/unhappy/lost customers, the importance of retaining customers, and actions an organization can take to handle customer complaints.

12[b] Explain the importance of customer satisfaction.

A] Explain the meaning of internal and external customers, customer perception of quality, and the benefits of customer retention and customer loyalty.

13[a] Explain the different types of control charts used for problem solving.

A] Discuss the salient features of control charts in general and the specific application of X bar chart, R chart, p chart, np chart, c chart, and u chart with sketches.

13[b] Explain the use of the seven new management tools for managing quality.

A] Explain the salient features and usage of Affinity diagram, relationship diagram, Tree diagram, Matrix diagram, Prioritization matrix, Process decision program chart, and Activity network diagram.

14[a] Explain the QFD process in detail.

A] Explain about QFD, discuss about the use of HOQ as a tool for implementing QFD, and explain the six components of the House of Quality through any example.

14[b] Explain the different steps involved in FMEA.

A] Give a brief introduction to the topic Failure Modes and Effects Analysis, explain the four stages in conducting FMEA, and the various components of the FMEA document.

15[a] Discuss the method of conducting quality audit for ISO 9000 certification.

A] Give the definition of the term ‘quality audit’, explain the stages in conducting quality audit, and the checklists for conducting audit.

15[b] Explain the requirements of Environmental Management Systems.

A] Explain the need for ISO 14000 as an Environmental Management System, the rationale behind its use, the various organizational and product evaluation standards, and the major elements of the EMS standards.

VLSI:Electronics & Communication Engineering 7th semester notes

2010-11-10T23:42:00.000-08:00

VLSI

DEPARTMENT OF ECE

EC1401: VLSI DESIGN

PART-A

UNIT I: CMOS TECHNOLOGY

What is latch-up?

· Latch-up is the shorting of the VDD & VSS lines in CMOS fabrication process due to parasitic circuit effect.

· Latch-up results in chip self-destruction or system failure.

How is a capacitor created in CMOS fabrication process?

· Capacitors are created in the CMOS fabrication process by adding at least one extra layer of polysilicon.

· Between the two polysilicon layers, a second thin-oxide layer is required.

· Diagram

List the materials used for masks in IC technology.

· Photoresist

· Polysilicon

· Silicon dioxide

· Silicon nitride

Draw the circuit of a CMOS 2 input NAND gate.

Refer figure 1.6 in Weste

What are the advantages of twin tub process?

· Used for protection against latch-up

· Provides separate optimization of p-type & n-type transistors

How is resistor created in CMOS fabrication process?

· If Polysilicon is left undoped, it is highly resistive. This property is used to build resistors.

· A resistive metal such as nichrome me be added to produce high value & high quality resistors.

· The resistor accuracy might be improved by laser trimming the resulting resistors on each chip to some predetermined test specification.

What is BiCMOS?

· BiCMOS is the combination of bipolar & CMOS transistors.

· To reduce the delay times of the highly loaded signals (microprocessor busses) and to provide better performance for analog functions the bipolar devices (npn or pnp) can be added to MOS transistors or vice versa.

What are the advantages of SOI process?

· There is no latch-up

· There are no body-effect problems

· No field-inversion problems

· Lower substrate capacitances provide the possibility for faster cirecuits.

What is the objective of the layout rules?

· To obtain a circuit with optimum yield in as small an area as possible without compromising reliability of the circuit.

What are the types of layout design rules?

Micron rule
Lambda based rule

What is guard ring?

· p⁺ diffusion in the P-substrate and n⁺ diffusion in the n-well are called guard rings that are used to collect injected minority carriers.

· When they are implemented in a structure, the n⁺ guard ring must be tied to VDD and the p⁺ guard ring must be connected to VSS.

· Guard rings must be included in the fabrication process to prevent I/O latch-up.

What is scribe line?

· The scribe line is a specifically designed structure that surrounds the completed chip and is the point at which the chip is cut with a diamond saw.

· The construction of the scribe line varies from manufacturer to manufacturer.

What is passivation or overglass?

This is a protective glass layer that covers the final chip. Openings are required at pads and any internal test points.

List the two techniques that can be used to prevent latch-up

Latch-up resistant CMOS process

Layout techniques

What are the types of oxidation?

Wet Oxidation: The oxidizing atmosphere contains water vapor

Dry Oxidation: The oxidizing atmosphere is pure oxygen

What are the advantages of EBL pattern generation?

· EBL: Electron Beam Lithography

· Patterns are derived directly from digital data

· There are no intermediate hardware images

· Different patterns may be accommodated in different sections of the wafer without difficulty.

· Changes to patterns can be implemented quickly.

What are the types of etching process?

Isotrophic etch

Fully anisotrophic etch

Preferential etch

What are the types of interconnect?

· Metal interconnect

· Polysilicon/Refractory interconnect

· Local interconnect

What is a thinox ?

· Thinox is an active mask formed which defines the areas where thin oxide are needed to implement transistor gates and allow implantation to form P or N-type diffusions for transistor source/drain regions.

How is the channel stop implant made?

· Channel stop implant is made by doping the P-substrate in areas where there are no N-transistors P⁺using a photo resist mask.

List the four main CMOS technologies

i. N-well process

ii. P-well process

iii. Twin-tub process

iv. Silicon on insulator.

UNIT II: MOS TRANSISTOR THEORY

Draw the structure of a nmos enhancement transistor.

Fig.2.3 pg 43

Draw the characteristics of a n- channel & p – channel enhancement transistor.

Fig 2.2 pg 42 Weste

What are the advantages of SiO₂ as a dielectric.

SiO₂ has a relatively low loss & high dielectric strength, thus application of high gate fields is possible.

State the 3 modes involved in the operation of an enhancement transistor

1. Accumulation mode 2.Depletion mode 3. Inversion mode.

What is a field induced junction?

In a pn junction the n- type conductivity is brought about by a metallurgical process, ie the electrons are introduced into the semiconductor by the introduction of donor ions. In an inversion layer substrate junction, the n- type layer is induced by the electric field E applied to the gate .Thus this junction instead of being a metallurgical junction is a field induced junction.

What are the factors that influence the drain current.

The distance between source and drain
The channel width
The threshold voltageVt
The thickness of the gate – insulating oxide layer
The dielectric constant of the gate insulator
The carrier(electron or hole) mobility, µ.

Define cut – off and saturated regions in the characteristics of an MOS transistor.

Cut – off current flow is essentially slow.

Saturated region – Channel is strongly inverted and the drain current flow is independent of the drain – source voltage.

Define threshold voltage and state the parameters on which it is dependent on.

Vt can be defined as the voltage applied between gate & source of an MOS device below which Ids effectively drops to zero. It is a function of

Gate conductor material
Gate insulation material
Gate insulator thickness - channel doping
Impurities at the silicon insulator interface
Voltage between the source and the substrate,Vsb.

Define Body effect.

· The threshold voltage Vt is not constant with respect to the voltage difference between the substrate and the source of the MOS transistor.

· So, when several MOS devices are connected in series, the threshold voltage is increased due to voltage difference between the substrate and the source. This effect of body or substrate voltage is called body effect.

What is channel length modulation?

· When an MOS device is in saturation, the effective channel length is decreased such that, L_eff = L - L_short .

Where L_short= √ 2(ε_si/qNa) (Vds – (Vgs – Vt))

· The reduction in channel length increases the W/L ratio, thereby increasing β as the drain voltage increases.

Draw the small signal model of a MOS transistor.

Fig 2.10 Pg 60

Define noise margin. Illustrate how it can be obtained from the transfer characteristics of a CMOS Inverter.

Noise margin is a parameter that allows us to determine the allowable noise voltage on the input of a gate so that the output will not be affected. The 2 common parameters are N_MH & N_ML Where

N_ML = | V_ILmax – V_OLmax| and N_MH = | V_OHmin – V_IHmin|

V_IHmin=minimum HIGH input voltage

V_ILmax = maximum LOW i/p voltage

V_OHmin = minimum HIGH o/p voltage

V_OLmax= maximum LOW o/p voltage

What is a transmission gate.

A transmission gate consists of an n- channel transistor and a p – channel transistor with separate gate connections and common source and drain connections. It gives good transmission of both logic 1 and logic 0.

Why is the transmission of logic 1 degraded as it passes through a nmos pass transistor.

When S = 1 (Vdd) , and Vin = 1 the pass transistor begins to conduct and charges the CL towards Vdd.Initially Vin is at ahigher potential than Vout, the current flows through the device. As voltage ot the load approaches Vdd – Vtn, the n- device begins to turn – off. Vtn is the n- transistor body effected threshold .. Thus the transmission of logic 1 is degraded.

What is a tristate inverter.

A tristate inverter is got by cascading a transmission gate with an inverter. When c = 0 and –c = 1, the output of the inverter is in a tristate condition.

Draw the structure & symbol of a CMOS tri - state inverter.

Fig 2.37 PG 91. Weste

Write the equation for total static power dissipation.

Ps = ∑ leakage current X supply voltage

n = no: of devices.

Define rise time( t_r ).

T_r is the time for a waveform to rise from 10% to 90% of its steady state value.

Define fall time ( t_f)

Time for a waveform to fall from 90% to 10% of its steady state value.

Define delay time,t_d.

Time difference between input transition and 50% output level .This is the time taken for a logic transition to pass from input to output. Fig 4.18 (a) Page 207 Weste.

UNIT III: SPECIFICATION USING VERILOG HDL

Write the syntax for switch primitive instantiation.

· Syntax: switch_name instance_name(output, data, control_input);

· Example: nmos n1 (out, data, control);

pmos p1 (out, data, control);

cmos c1 (out, data, ncontrol, pcontrol);

List out different data types in verilog.

· Net type: It represents a physical connection between structural elements. Ex: wire

· Register type: It represents an abstract data storage element. It is assigned values only within an always statement or an initial statement. Ex: reg

Give the symbol, Truth table and syntax of bufif1.

Truth table:

	Control input
Input		0	1	x	Z
	0	z	0	L	L
	1	z	1	H	H
	x	z	x	x	x
	z	z	x	x	x

Syntax: bufif1 n1 (out, input, control);

Symbol:

Give the structural coding of an Half adder

module HA (a, b, sum, carry)

input a, b;

output sum, carry;

xor (sum, a, b);

and (carry, a, b);

endmodule

What are the types of modeling in verilog?

Structural
Data flow
Behavioral

What is HDL?

· HDL: Hardware Description Language

· HDL is a standard language to describe the operations of digital circuits.

Name two types of HDLs.

· Verilog

· VHDL: Very High Speed Integrated Circuits Hardware Description Language.

What is module?

· A module is the description of a unit that performs some function.

· The basic unit of description in verilog.

· It describes the functionality or structure of a design.

· It describes the ports through which it communicates with other modules.

What is the difference between initial and always statement?

· Initial statement: It executes only once.

· Always statement: It executes in a loop i.e. it is executed repeatedly.

What is inter-statement delay?

· Inter-statement delay: The delay by which a statement’s execution is delayed.

· Example: sum = (A^B)^C;

#4 carry = A&B + A&C + B&C;

· The delay in the second statement specifies that the execution of the assignment is to be delayed by 4 time units, and then executes the second assignment.

What is intra-statement delay?

· Intra-statement delay: The delay between computing the value of the right-hand side expression and its assignment to the left-hand side.

· Example: Sum = #3 (A^B)^C;

· The delay in this statement means that the value of the RHS expression is to be computed first, wait for 3 time units, and then assign the value to the sum

List any two capabilities of verilog.

· Primitive logic gates such as AND, OR & NAND are built-in into the language.

· Flexibility of creating a user-defined primitive (UDP). This UDP can be either combinational or sequential logic primitive.

What are the types of event control?

· Regular event control (edge-triggered )

· Named event control

· Event OR control

· Level-sensitive timing control

What is value set?

· Verilog supports four values to model the functionality of real hardware.

Value levels	Conditions in hardware circuit
0 1 x z	Logic 0, false Logic 1, true Unknown value High impedance

Define net.

· Net is a data type that represents a physical connection between structural elements.

· Its value is determined from the value of its drivers.

· The default value to a net is Z.

· Nets are declared with the keyword wire.

· It can be declared as scalar or vector.

Write the syntax for gate primitive instantiation.

Gate_name instance_name (out, in_1, in_2, in_3, …….);

Example: and g1 (c, a, b);

or g2 (c, a, b);

Define a port. How is it declared?

· Ports are interface terminals that allow a module to communicate with other modules. These corresponds to the input and output points on a library cell.

· All ports must be declared within a module lisiting.

· Unidirectional port can be declared as

input in_1, in_2;

output out_1, out_2;

· Bidirectional port can be declared as

inout IO_1, IO_2;

Define an identifier.

· Identifiers are names of modules, variables, and other objects that can be used in the design.

· Identifiers consist of upper & lower case letters, digits 0 through 9, the underscore character( _ ) and the dollar sign ($).

· The first character must be a letter.

What is UDP?

· User Defined Primitives are self-contained and do not instantiate other modules or primitives.

· UDP declaration: primitive UDP_name (port list);

· Two types of UDP: 1. Combinational

2. Sequential

List the types of Gate delay

· The signal propagation delay from any gate input to the gate output can be specified using a gate delay.

· The gate delay can be specified in the gate instantiation itself.

· Types of gate delay.

i. rise delay

ii. fall delay

iii. turn-off delay

What are the types of structural modeling?

· Switch instantiation (at the transistor level)

· Gate instantiation (at the gate level)

· Module instantiation (to create hierarchy)

· UDP instantiation (at the gate level)

What are the types of procedural assignment?

(i) Blocking Procedural assignment:

· A procedural assignment in which the assignment operator is an “=” is a blocking procedural assignment.

· The assignment statement is executed before the next statement is executed.

· Blocking assignment statements are executed in the order they are specified in a sequential block.

(ii) Non-blocking procedural assignment:

· In a non-blocking procedural assignment, the assignment symbol “<=” is used.

· I t allow scheduling of assignment without blocking execution of the statements that follow in a sequential block.

What is the difference between reduction operator & bitwise operator?

· Reduction Operator: It performs a bitwise operation on a single vector operand and yield a 1-bit result.

· Bitwise Operator: It performs bitwise operation between two vector operands and yield vector result.

· Example A=4’b1010; B=4’b1101;

Z=A&B = 4’b1000 -------------- Bitwise AND operation

Z=&A=1’b0 ---------------- Reduction AND operation

What is replication operator?

· Replication operator is used to concatenate the same number to the specified number of times.

· Example: A=4’b1010; Z={ 2 {A}}=8’b1010 1010

· In the above example, 2 is the replication constant that specifies how many times to replicate the 4-bit number A inside the bracket.

UNIT IV: CMOS CHIP DESIGN

Draw the symbols of N & P – switches.

Fig 1.2 pg 7 Weste

What is a crowbarred state.

In an inverter when both pull – up & pull down gates are simultaneously turned ON, a crowbarred state exists. This causes an indeterministic logic level and also causes static power to be dissipated. It is an unwanted condition.

Draw a CMOS NAND gate with its pull – up & pull – down Truth table.

Fig 1.6 Table 1.4 & table 1.5 pg 12 Weste.

Draw the symbol of a 2 i/p CMOS Mux.

Fig 1.11 Pg 18 Weste. Table 1.9 Pg 18

Draw a CMOS positive level sensitive D latch.

Fig 1.12 Pg 19 Weste

What is 22V10?

· 22V10 is an industry standard PAL device.

· Characteristics: 12 inputs,

10 I/Os,

24 pins

# Product terms: 9 10 12 14 16 14 12 10 8

· I/O structure of 22V10 has a register, output 4:1 MUX, input 2:1 MUX and tristate buffer.

What is CLB?

· CLB: Configurable Logic Blocks

· CLB is a basic element (cell) in FPGA.

· CLB is used to implement different logic functions.

When is a full custom ASIC designed.?

A full custom ASIC is designed if there is no suitable existing cell libraries available that can be used for the entire design or they are not fast enough or they consume too much power A full custom ASIC is designed when the technology is new or very specialized.

What is a wafer lot?

A wafer lot is a group of silicon wafers that are all processed together. Usually between 5 to 30 wafers are in a lot.

What is a mega cell.

The standard - cell areas may be used in combination with larger predesigned cells, such as microcontrollers, or microprocessors Which are called mega cells/megafunctions/system – level macros/ fixed blocks/cores/functional standard blocks.

What is a gate array?

In a gate array (GA) the transistors are predefined on the silicon wafer. The predefined pattern of transistors on a gate array is the base array and the smallest element that i9s replicated to make the base array is the base cell or primitive cell.

What are the types of Masked gate arrays

· Channeled gate array

· Channelless gate array

· Structured gate array.

List the features of Channeled gate array , Channelless gate array ,Structured gate array.

Channeled gate array: a)Only interconnect is customized

b)The interconnect uses predefined spaces between rows of

base cells.

c) Manufacturing lead time is between 2 days and 2 weeks.

Channelless gate array : a) only some mask layers are customized

b) Manufacturing lead time is between 2 days and 2 weeks.

c) No predefined areas set aside for routing between cells.

Structured gate array: a) Only interconnect is customized

b) Custom blocks can be embedded

c) Manufacturing lead time is between 2 days and 2 weeks.

List the features of PLD .

No customized mask layers or logic cells

Fast design turnaround

A single large block of programmable interconnect

A matrix of logic macrocells that usually consist of programmable array logic followed by a flip – flop or latch.

What are the types of PLD’s.

ROM, PROM, EPROM, EEPROM, UVPROM., Masked ROM, PAL, PLA etc.

Essential features of FPGA.

· None of the mask layers are customized

· Has a method for programming the basic logic cells & interconnect

· The core is a regular array of programmable basic logic cells that can implement both combinational & sequential logic

· A matrix of programmable interconnect surrounds the basic logic cells

· Programmable I/o cells surround the core

· Design turnaround is few hours.

UNIT V: CMOS TESTING

List some typical defects in the manufacturing of IC.

Layer to layer shorts
Discontinuous wires
Thin – oxide shorts to substrate or well.
Nodes shorted to ground or power
Nodes shorted to each other
Inputs floating
Outputs disconnected

What are SA0 & SA1 faults.

When anode in a circuit is permanently at logic 1 or 0 due to thin oxide shorts , ie the n – transistor gate to Vss or the p – transistor gate to Vdd or meta to metal shorts. The SA0 or SA1 Fault occurs.

Define observability and controllability.

Observability: The observability of a particular internal circuit node is the degree to which one can observe that node at the outputs of an integrated circuit. Controllability : It is the measure of the ease of setting an internal node to 1 or 0 state via primary inputs. A well designed circuit should have all nodes easily controllable.

What is fault sampling?

Fault sampling is one of the approaches to fault analysis. It is used in the circuit where it is impossible to fault every node in the circuit. In this approach, nodes are randomly selected and faulted.

What is a sensitized path?

In D – alg one objective is to propagate a fault at a particular node to one or more primary o/p This path to the o/p pin is called a sensitized path.

What are primary i/p’s and o/p’s?

A primary output(Po) is adirectly observable signal ,such as a pad or a scan o/p .A primary input is one that can be directly set via a pad or some other means.

State the 3 types of fault simulation process.

Serial simulation 2. Parallel simulation 3. Concurrent simulation.

8. What is delay fault testing.

In the case of a high powered NAND gate composed of paralleled n - & p –

transistors, if an open ckt occurs as in fig 7.10 pg 483 Weste the gate would still

function but with increased pull down time. This is a delay fault.

9. What is ILA testing.

An iterative logic array is a collection of identical logic modules . An ILA is C – testable if it can be tested with a constant number of input vectors independent of the iteration count. An ILA is I - testable if a particular fault that occurs in any module as a result of an applied input vector is identical for all modules in an ILA.

10. What are the advantages & disadvantages of IDDQ.

As IDDQ is based on quiescent current measurement which is time consuming, the tests must be run slower than normal ,thus increasing the test time. However this technique gives a form of indirect massive observability at little overhead.

11. What are the various connections of a Test Access Port.(TAP).

The TAP has 4 or 5 single bit connections. They are

· TCK(the test clock input) – used to clock tests into & out of chips.

· TMS ( The test mode select) – used to control test operations.

· TDI ( the test data input) – used to input test data to a chip.

· TDO ( test data output) used to output test data from a chip.

It also has an optional signal

· TRST( The test Reset Signal) used to synchronously reset the TAP controller: also used if a power – up reset signal is not available in the chip being tested.

12. Describe the test architecture of a boundary scan using TAP.

Fig 7.25 pg 502 . Basic test architecture consists of

· The TAP interface pins

· A set of test data registers to collect datafrom chip

· An instruction register to enable test inputs

· A TAP controller, which interprets instructions & controls the flow of data.

13.What is a TAP controller.

The TAP controller is a 16 state FSM that proceeds from state to state based on TCK & TMS signals. It provides signals that control the test data registers & instruction registers.

14.Explain BYPASS ,EXTEST, SAMPLE /PRELOAD.

The instruction registers has to decode 3 instructions they are.

BYPASS – This instruction is represented by an IR having all zeroes in it. It is

used to bypass any serial data registers in a chip with a 1 – bit register. This

allows specifis chips to be tested in a serial scan scan chain without having to

shift through the accumulated SR stages in all the chips.

EXTEST – This allows for the testing of off chip circuitry & is represnted by all ones in the IR.

SAMPLE /PRELOAD: - This instruction places the boundary scan register in the DR chain and samples or preloads the chip i/os.

15.What is a test DR.

The test data registers are used to set the inputs of modules to be tested and to collect the results of running tests.

16.What are boundary scan registers?

The boundary scan register is a special case of a data register. It allows circuit board interconnections to be tested, external components tested, and the state of chip digital I/Os to be sampled.

Microwave:Electronics & Communication Engineering 7th semester notes

2010-11-10T23:40:00.000-08:00

Microwave

Unit - I

1. Why h, y or z parameters cannot be used at microwave frequencies.

Suitable equipments are not available at microwave frequencies for the measurements of voltages and current at the ports of the networks

Short circuit and open circuit conditions are difficult at these frequencies.

Active devcies like power transistors, tunnel diodes etc don’t have suability under open /short circuit conditions.

2. What is the frequency range of C and S BANDS?

C band- 4 to 8 GHz

S band 2 to 4 GHz

3. Name any four applications of microwave frequencies

Long distance communications such as repeaters

aircraft altimeters

vulcanization in rubber industries

polymerization in the chemical industries

4. Voltmeters and ammeters do not exist at microwave frequencies why?

They are not stable at microwave frequencies

5. Explain the need for S parameters

At microwave frequncies, ammeters and voltmeters do not exist and it is not possible to use h, y or z parameters. Hence the linear relationship between the incident transmitted waves and reflected waves are measured in the form of s-parameters in order to study the behaiveiour of s-matrix.

6. List the properties of s matrix

Unityproperty, Symmetry, zero, phase shift property

7. For a two port junction define S11, S12, S21 and S22

S11=Reflection coefficient measured at port1 when V1 exists and port2 is matched.

S12=Reflection coefficient measured at port1 when V2 exists and port1 is matched.

S21=Reflection coefficient measured at port2 when V1 exists and port2 is matched.

S22=Reflection coefficient measured at port2 when V2 exists and port1 is matched.

8. In what way the low frequency concepts are useful at microwave frequencies.

In order to carry out a simplified analysis for waveguide theory as is done in the circuit theory.

9. Write a scattering matrix for a 2port and explain the parameters involved

S= S11 S12

S21 S23

Where

S11=Reflection coefficient measured at port1 when V1 exists and port2 is matched.

S12=Reflection coefficient measured at port1 when V2 exists and port1 is matched.

S21=Reflection coefficient measured at port2 when V1 exists and port2 is matched.

S22=Reflection coefficient measured at port2 when V2 exists and port1 is matched.

10. What is the condition under which S parameters are equal to their corresponding traanposes, S=S^T?

When a junction is said to be a reciprocal junction the s-matrix satisfies the symmetry property and the S-matrix is equal to its corresponding transposes, S=S^T.

11. What are called S PARAMETERS?

The linear relationship described between the incident /transmitted waves and the reflected waves are called S-pramterrs.It is a measure of the reflection/transmission coefficient at any port of the microwave network.

12. Draw a 2 port network with ABCD parameters.

2 port network

____ ______

____ _____

V1=AV2-BI2

I1=CV2-DI2

13. What is the X-band frequency range?

8.2 GHz to 12.4 GHz

14. Write down the parameter equations in matrix form for a 2post network

Z= Z11 Z12

Z21 Z22

Z11=V1/I1 at i2=0; input impedance (driving point impedance at port 1) when port2 is open circuited.

Z12=V1/I2 at i1=0; reverse transfer impedance with port1 open circuited.

Z21=V2/I1 at i2=0; reverse transfer impedance with port1 open circuited.

Z22=v2/i2 at i1=0; output impedance (driving point impedance at port 2) when port1 is open circuited.

Part B

1.Briefly explain Waveguide Tees.

2.Write short notes on rat-race circuits.

3.With neat diagram explain the working principle of Directional couplers.

4.Write short notes on Circulator & Isolator.

5.Write short notes on Corners, Bends & Twist.

6.Derive the S-matrix for 2 Hole Directional coupler.

7. Derive the S-matrix for Circulator.

8.Derive the S-matrix for Isolator

9.Write short notes on E-plane & H-plane Tee.

10. Why we need S-matrix for Microwave analysis, write the S-matrix for 2 port network.

UNIT - II - (PART A ANSWERS)

Compare & contrast waveguides & transmission lines.

Wave Guides	Transmission lines
Used at microwave frequencies & less lossy at high frequencies	Used at conventional lower frequencies & more lossy
Conduction through the dielectric filling the waveguide	Conduction through walls
Behaviour & properties in terms of electrical & magnetic fields	Behaviour & properties in terms of voltages & currents
Power handling capability very high	Power handling capability less

Explain the significance of ferrite devices in microwave circuits. (Apr’2K, Oct’2K)

Ferrite devices changes the polarization of the waves that passes through them. This is useful for the construction of unidirectional devices such as isolators & circulators

3. Explain the function of Gyrator. ( Oct’97,98,99)

A gyrator is a device that produces 180 degrees phase shift of waves progressing

in forward direction, but no phase shift in the reverse directon.

Give two applications of gyrator.

Can be used as a non reciprocal phase shifter.

Can be used as in transmitters as local oscillators.

Explain a typical application of a circulator. ( Oct’2K)

Multiple isolation in radars, parametric amplifiers.

List the different types of directional couplers.

Bethe hole DC, crossed guide DC, coupled line couplers, branch line couplers, and Lange DC are the different types of directional couplers.

Explain the purpose of tuning plunger in a variable type termination.

It varies the location of the terminal plane which in turn changes the wave pattern and hence VSWR.

What is the working principle of a microwave phase shifters. ( Oct’2K)

A change in the path length or the phase constant produces a shift in the phase in phase shifters.

Bring out the differences between a directional coupler and a magic Tee.

In a directional coupler the output is coupled into only one port and all other ports are matched, whereas in a magic Tee the output is split between any two ports while all the other ports matched.

Directional coupler is a unidirectional device whereas a magic Tee produces phase variation in the wave in all ports irrespective of the direction n which it travels.

Magic Tee produces combined output of two sources connected at a time, whereas a DC handles a single source at a time.

Define the two performance factors of directional couplers. ( Nov’96, Apr’98)

The two performance factors of DC are the Coupling Factor and Directivity. Coupling Factor defines the ratio of the amount of power coupled in coupled port to that of power at input port in decibels. Directivity is defined as the ratio of powers at the isolated port and the incident ports at decibels.

What is meant by matched termination?(Oct’97).How can it be achieved.(Oct’2K)

Matched termination provides a termination of a network with its characteristic impedance, i.e. VSWR = 1. This can be achieved by totally avoiding the reflections and all the power that is fed to the output port s absorbed at the output port itself and not reflected.

Differentiate fixed & variable attenuators. ( Oct’97 )

Fixed attenuators provide fixed amount of attenuation (3,10 or 20 dB), whereas variable attenuators provide variable amount of attenuation ranging from

(0 to ∞ dB).

What is meant by Isolator? ( Apr’ 98 )

Isolators are unidirectional device which isolates the source and load by providing no amount of attenuation in the forward direction and infinite amount of attenuation in the reverse direction.

Define Insertion Loss & isolation of a microwave device. ( Oct’ 2000)

Insertion loss is the forward transmission loss ( ≈ dB ) in decibels measured when the isolator is connected in the forward direction, i.e. from source towards load. When the isolator is connected in the reverse direction, the reverse attenuation will be high ( ∞ dB ) as measured in the difference in the power outputs of the input and output ports – isolation loss.

16.Write the equation of VSWR. (Oct’ 98, Apr’ 2K)

VSWR = V max / V min

List the various WG bends in microwave ( Ocy’99 )

E plane bends and H plane bends are the various WG bends in microwave.

What is meant by circulator? ( Apr’ 2K )

A circulator is a 3 – port isolator. The power from one port is coupled to the immedialtely next port in a sequential fashion. For ex. Input power at 1 will give almost all of this power at port 2, while port 3 is matched. 1→ 2, 2 → 3, 3 → 1 is only possible and not in the reverse manner.

Part B

1. Explain with neat diagram Microwave Bipolar transistors.

2. Explain Gunn Effect & RWH Theory of Gunn Diode.

3. Explain various modes of operation in Gunn Diode.

4. Write short notes on IMPATT Diode.

5. Write short notes on TRAPATT Diode.

6. Write short notes on Parametric up converter & down converter.

7. Write short notes on Parametric Amplifier.

Unit - III

What is meant by Applegate diagram?

Applegate diagram is the distance-time diagram used to plot the velocity of the electrons in klystrons.

List the different types of Magnetrons

Negative Resistance magnetrons
Cyclotron frequency magnetron
Traveling wave magnetrons

Which tube is used for high power microwave generation.

Magnetron is used for high power microwave generation

Explain Hull Cut-off condition

Hull cut-off condition gives the cut-off magnetic field in a magnetron such that the electron grazes the anode and returns back to the cathode.

Explain phase focusing effect in magnetrons

The alternating field applied in magnetron changes its phase in such a way that the electrons spend more time in the interaction space and form bunches with the favored electrons. This effect is known as Phase focusing effect.

What are slow wave structures?

Slow wave structures are used to reduce the phase velocity of the wave traveling in waveguides.

How a Helix structure is useful for SWS?

A helical structure is basically a slow wave structure which is used to reduce the phase velocity of the traveling wave. This enables a continuous interaction between RF field and the electron beam which in turn amplifies the input wave exponentially.

What is meant by ‘Strapping’ in magnetrons?

In order to prevent mode jumping in magnetrons, two rings of heavy gauge wire is used to connect alternate anode poles. This is called as strapping.

What is the use of admittance spirals in klystrons?

Admittance spirals are the loci of admittances of Reflex klystron plotted in rectangular coordinates. The necessary condition for sustained oscillation can be marked in this diagram in order to differentiate the oscillation and non-oscillation regions. This diagram also shows that the power output in Reflex klystron is discontinuous because the admittance plot spirals out both in the oscillation and non-oscillation regions.

What is meant by pushing and pulling in magnetrons?

The change in resonant frequency of the magnetron due to changes in the anode voltage is called frequency pushing whereas the change in resonant frequency of the magnetron due to changes in load impedance is called frequency pulling.

List the advantages of Reflex klystron over multi-cavity klystrons.

Reflex klystrons can be used as an oscillator without any complex feedback circuitry as required in multi-cavity klystrons. As it is a narrow bandwidth device it can be tuned to operate at a single desired frequency in resonant circuits.

Define drift space of a klystron tube.

The drift space is the space between the buncher cavity and the catcher cavity in klystron tubes.

Explain back-heating effect in microwave tubes

The electrons fall back toward the cathode itself due to transit time effect and heats up the cathode increasingly. This is called back heating effect.

Why should the repeller voltage be more negative than the beam voltage in a single cavity klystrons?

If the repeller voltage becomes less negative or even positive with respect to beam voltage then the electrons hit the repeller with a greater force and the repeller draws more current which causes permanent damage to it. Hence repeller should be maintained at a more negative potential than the beam voltage in reflex klystrons.

Why Π mode is preferred for magnetrons?

Π mode is preferred in magnetrons since it provides self-consistent oscillation and increased power output when compared to any other modes.

Explain the need for attenuators in TWT

Attenuators are used to attenuate the unwanted signal traveling towards the input end due to reflections arising from impedance mismatch.

What is meant by velocity modulation?

The change in the velocity of the electrons under the influence of an alternating field is termed as velocity modulation

The spacing between intermediate cavities in a multi cavity klystron decreases. Why?

To achieve maximum degree of bunching the distance between any two cavities must be an optimum one. This distance L_opt inversely proportional to V1, the amplitude of RF voltage setup in the subsequent cavities. Since electrons are once agin velocity modulated in every cavity, V1 keeps growing and L_opt diminishes. Hence the intercavity distance decreases in a multi cavity klystron.

What is the maximum electronic efficiency of a Reflex klystron?

22.7 % is the maximum efficiency of a Reflex klystron.

Bring out the differences between electronic tuning and mechanical tuning in a single cavity klystron.

In electronic tuning the repeller voltage is varied to obtain changes in resonant frequency whereas in mechanical tuning a mechanical screw adjustment produces a change in the physical size of the cavity to produce changes in resonant frequency.

Which is the best suitable time for the electrons to come back to the cavity in the Reflex klystron?

The best suitable time for the electrons to come back to the cavity in a Reflex klystron is n+3/4 cycles with respect to the reference electron starting from cavity where n is a positive integer. N=1 gives more power output.

Define transit time in a Reflex klystron.

The time taken by electron to travel into the repeller space and come back toward the cavity is called the transit time in Reflex klystron.

Bring out the differences between the TWT & Klystron

TWT	Klystron
High BW More gain Use non-resonant structures Continuous interaction between electron beam and RF voltage	Narrow BW Less gain Use cavity resonators Discontinuous interaction between electron beam and RF voltage

State the output power & frequency range of oscillation of a reflex klystron.

In a RK the output power ranges from 10 mW to 2.5 wW and output frequency ranges from 4 GHz to 200 GHz

In Klystron, at what value of X(bunching parameter) the fundamental current component has its maximum value

X = 1.841

What is meant by bunching?

The electrons traveling with different velocities join together at their transit towards the output end. This collection of different velocity modulated electrons is called bunching

What is the basic difference between klystron and Reflex klystron?

Klystron can be readily used as an amplifier whereas RK can be used as an oscillator.

List the characteristics of TWT

posses a reduced phase velocity of the waves through a SWS
has a high bandwidth and excellent gain

PART B

1. Explain Velocity Modulation & Bunching process of Klystron.

2. Derive output power & Efficiency of Klystron.

3. Explain Velocity Modulation & Bunching process of Klystron Amplifier.

4. Derive output power & Efficiency of Klystron Amplifier.

5. Explain Helix TWT Amplifier in detail.

6. Briefly explain Magnetron Oscillators.

7. Write short notes on different types of Magnetron Oscillators.

UNIT IV

What is the value of ‘Saturated drift velocity’ of electrons in a semiconductor?

Saturated drift velocity of electrons in a semiconductor is 6 * 10^6 m/s.

What is the maximum value of E-field that can be sustained in a semiconductor?

And without having dielectric breakdown for germanium and silicon.

Maximum value of E field that can be sustained in Ge is 10^5 v/cm and 2*10^5 v/cm.

What are the high frequency limitations faced by the semiconductors of

microwave frequency ?

High frequency limitations are

a) Transit time effect leads to difficulty in specifying the performance of the

Transistors. || and || value become complex

b) Interelectrode capacitance depends on width of depletion layers of the

Junction which is inturn bias dependent. Lead inductances effect are lesser

Than in tubes.

What are the variouis microwave transistors structures?

Inter ditated, matrix and overlay are the various microwave transistor devices.

What is meant by TEDs?

TEDs are transferred electron devices where there is a transfer of electron from a

lower valley of higher mobility to a n upper valley of lower mobility in the conduction band on application of kinetic energy greater than thermal energy but less than forbidden energy gap.

What are the various materials used for Gunn diodes?

GaAs, InP, CdTe, InAs are materials used in Gunn diode.

Why are electrons very hot in TEDs?

It is operated well above the thermal energy of electrons hence the electrons are very hot.

List difference between tranistor and TEDs

Transistor TED

1. Depends on junction property Depends on bulk property

2. Use elemental semiconductor Use compound semiconductor

3. Electrons are warm Electrons are very hot.

What is the difference between negative resistance tunnel diode and negative

Resistance TEDs?

In negative resistance tunnel diodes tunneling of electrons takes place through allowable empty energy states whereas in negative resistance TEDs, electrons enters into a negative differential mobility state which produce negative resistance effect.

Explain the effect of empty energy band in TEDs.

As the imparted energy increases above the thermal energy, the electrons crosses the narrow forbidden energy gap and enters into the empty energy band whre there is negative differential mobility of electrons.

Why low frequency oscillations cannot be obtained from TEDs.

Due to bulk property of the material as the voltage is increased above the threshold voltage due to negative resistance effect, it produces high frequency oscillations due to its bulk property. So it cannot produce low frequency oscillation.

Explain the plasma formation and plasma extraction in TRAPATT diodes.

As avalanche takes places a plasma of electrons and holes is generated placing a large potential across the junction which opposes the applied voltage,. The total voltage is hereby reduced and current pulse is trapped behind it. When this pulse travels across n drift region and reaches the end plasma extraction takes place and one again voltage increases.

TRAPATT mode can operate at comparatively low frequenicies. Why?

Because the drift velocity in a TRAPATT dioe is much less than in a IMPATT diode the operating frequencies are lower.

What are the four different modes of operation of GUNN diode.

Gunn oscillation mode, stable amplification mode, LSA oscillation mode and bias current osillation mode.

What are the 3 possible domain modes for Gunn oscillation modes in a gunn

diode ?

Transit time domain mode, Quenched and delayed domain mode and LSA

oscillation domain mode.

Expand the terms IMPATT and TRAPATT.

IMPATT - Impact Avalanche and Transit Time diode

TRAPATT – Trapped plasma Avalanche Triggered Transit mode.

What is meant by LSA oscillation mode in Gunn diode?

In LSA oscillation mode, stable and sustained oscillations are produced. The transit time frequency is an integral multiple of the domain growth time constant.

What is meant by IMPATT and TRAPATT mode.

In IMPATT mode avalanche of charge carriers are produced and the applied voltage and pulsed current output are 180 degree out of phase whereas in TRAPATT mode due to plasma formation a current pulse is trapped and plama gets slowly extracted.

What is Gunn effect/

Gunn effect was first observed by GUNN in n-type GaAs bulk diodes. According to GUNN above some critical voltage corresponding to an electric field of 2000-4000 v/cm the current in every specimen became a fluctuating function of time. The frequency of oscillation was determined mainly by the specimen and not by the external circuit.

What is avalanche transit time effect?

Due to excess of charge carriers produced there is a delay in charge carriers moving towards the other terminal of the diode. This effect is called avalanche time effect.

PART B

1. Briefly Explain Gunn Effect & modes of operation of the Gunn Diode.

2. Explain Physical description, Avalanche Multiplication & Carrier current & External Current of Read Diode.

3. Explain Physical structure, negative resistance, power output & efficiency of IMPATT Diode.

4. Explain Physical structure, negative resistance, power output & efficiency of TRAPATT Diode.

5. Explain Physical structure, negative resistance, power output & efficiency of BARITT Diode.

6. Explain Manley –Rowe Power relation & Parametric Amplifier.

7. Explain Microstrip lines in detail.

8. Explain Different types of Microstrip lines.

9. Explain the procedure for Monolithic Microwave integrated circuits.

UNIT V

1. What devices are used in tunable detectors ?

Specially designed point contact diodes or semiconductor schottky

barrier diodes.

2. For which parameter measurement is the slotted line section used?

a. VSWR

b. wavelength

c. impedance

d. reflection co-eff & return loss.

3. what is a VSWR meter ?

A VSWR meter is a sensitive high gain , high Q ,low noise voltage

amplifier tuned at a fixed frequency of 1 khz to which the microwave signal

is down modulated.

4. what is a spectrum analyser?

A spectrum analyser is a broad band super heterodyne receiver which

plots the amplitude vs freq of the received signal.

5. list the basic design considerations of a spectrum analyser?

· Freq sweep rate

· Freq sweep rangr

· B.W of IF amplifier

· Center freq of IF amplifier.

6. What is the disadvantage of using a slotted line section?

The amplitude & phase measurements are limited to a single freq.

7. What is a network analyser?

A n/w snslyser measuers both the amplitude & phase of a signal over

a wide freq range within a reasonable time.

8. What sensors are used for power measurements?

· Schottky barrier diode

· Bolometer

· Thermocouple

9. Explain the principle used in low power measurements .

Power meter consisits of a power sensor, which converts the microwave power to heat energy , the corresponding temp rise provides a change in the electrical parameters resulting in an o/p current in low freq circuitry which indicates the power.

10. Explain the principle used in high power measurements.

High power measurement uses uw calorimeters in which temp rise of the load provides a direct measure of the power absorbed by the load.

11. What are the 2 most common types of bolometer?

· Barretter

· Thermistor

12. What are the 2 types of calorimeters used?

· Static calorimeter

· Circulating calorimeter

13. What are the 2 calorimeteric methods ?

· Direct heating

· Indirect heating

14. Define insertion loss & return loss.

Insertion loss = 10 log p0/p1.

Return loss = 10 log pr/pi = 20 log I T’I where T’ =reflection co-eff.

15. Describe the principle of wavemeter freq measurement.

A wavemeter is a cylindrical cavuty with a variable short ckt termination which changes the resonance freq of the cavity by changing the cavity length.

PART B

1. Explain Slotted line VSWR Measurement.

2. Explain VSWR through return loss Measurement.

3. Explain Power Measurement.

4. Explain Impedance Measurement.

5. Explain Insertion loss & Attenuation Measurement.

6. Explain Measurement of Scattering parameters.

7. Explain Dielectric constant Measurement of a solid using Waveguides.

Microwave:Electronics & Communication Engineering 7th semester notes

2010-11-10T23:38:00.000-08:00

SUBJECT : Microwave Engineering CODE : EC 1403

BRANCH : ECE SEM : VII

DURATION : 3 Hrs MAX MARKS : 100

NOTE: ANSWER ALL QUESTIONS

SCHEME OF EVALUATION

PART – A (10 X 2 = 20)

Why H,Yor Z parameters cannot be used at microwave frequency

Suitable equipments are not available at microwave frequencies for the measurements of voltages and current at the ports of the networks

Short circuit and open circuit conditions are difficult at these frequencies.

Active devcies like power transistors, tunnel diodes etc don’t have suability under open /short circuit conditions

Name any four applications of microwave frequency

Long distance communications such as repeaters

aircraft altimeters

vulcanization in rubber industries

polymerization in the chemical industries

Define Symmetry property of S-Matrix

Attenuation of wave travel from port 1 to port 2 is equal to the attenuation of wave travel from port 2 to port 1

What is transferred electron effect

TEDs are transferred electron devices where there is a transfer of electron from a

lower valley of higher mobility to a n upper valley of lower mobility in the conduction band on application of kinetic energy greater than thermal energy but less than forbidden energy gap.

Define the term parametric device

Producing the nonlinear effects in microwave frequency range

Write the S matrix for Isolator

S = 0 0

1 0

7. Writs any two properties of Ferrite Devices.

i) Forward characteristics are not equal to the reverse characteristics

ii) Providing phase shift in the incoming signal

Compare Transistor with TED

Transistor TED

1. Depends on junction property Depends on bulk property

2. Use elemental semiconductor Use compound semiconductor

3. Electrons are warm Electrons are very hot.

What is voltage controlled mode and Current controlled mode.

Voltage controlled mode- Current can be multi valued

Current controlled mode- Voltage can be multi valued

Define Gunn Effect

PART - B (5 X 16 = 80)

11. a) Explain the working principle of microwave isolator & write its S-matrix

Diagram - 6

Construction and working principle - 6

S matrix – 4

(OR)

b) Explain about two hole directional coupler construction & its working

principle

Performance characteristics of DC - 6

S Matrix derivation – 10

12. a) Explain E plane & H plane Tee operation with diagram.

E plane Tee operation and S matrix – 8

H plane Tee operation and S matrix – 8

(OR)

b) Explain Hybrid –ring circuit with diagram

Diagram - 6

Construction and working principle - 6

S matrix – 4

13. a) Explain the Properties of S Matrix. Also prove the Symmetry property

Zero diagonal property - 4

Symmetry property - 4

Unitary property - 4

Phase shift property – 4

(OR)

b) Explain Manley Rowe power relation & application of parametric amplifier

Diagram -4

Parametric amplifiers - 4

Parametric Up Converter - 4

Parametric Down Converter- 4

14. a) Write short notes on (1) Microwave generation (2) Microwave amplification

Microwave Amplification - 8

Microwave Generation – 8

(OR)

b) Explain the transit time limitation & power frequency limitation of microwave bipolar transistor

Due to excess of charge carriers produced there is a delay in charge carriers moving towards the other terminal of the diode. This effect is called avalanche time effect. - 4

Voltage Frequency limitation - 4

Current Frequency limitation -4

Power Frequency limitation – 4

15. a) Distinguish between transit & TEDs . Also explain the High Field Domain and Modes of Oscillation

Transit time domain mode, - 4

Quenched and delayed domain mode and - 8

LSA oscillation domain mode – 4

(OR)

b) Write short notes on i) BARITT diode

ii) TRAPATT diode

Construction – 5

Working principle - 6

Power output and Efficiency - 4

SUBJECT : Microwave Engineering CODE : EC 1403

BRANCH : ECE SEM : VII

DURATION : 3 Hrs MAX MARKS : 100

NOTE: ANSWER ALL QUESTIONS

PART – A (10 X 2 = 20)

Mention the basic materials required for microwave integrated circuit

Substrate Material, Conductor material, Resistive, Dielctric

List the various types of striplines used in MMIC

Strip Lines, Micro strip lines

What are slow wave structures?

Slow wave structures are used to reduce the phase velocity of the wave traveling in waveguides.

List the different types of Magnetrons

Negative Resistance magnetrons

Cyclotron frequency magnetron

Traveling wave magnetrons

List the advantages of Reflex klystron over multi-cavity klystrons

What is meant by velocity modulation?

The change in the velocity of the electrons under the influence of an alternating field is termed as velocity modulation

What is the maximum electronic efficiency of a Reflex klystron?

22.7

8. List out the different types of losses involved in micro strip lines

Dielectric loss , Ohmic Skin Loss, Radiation Loss

What is parallel strip line?

Two parallel plate in between conducting material

Write the Advantages of Micro strip lines

Low cost , Less size, Low power

PART – B (5 X 16 = 80)

11. a) Explain the working principle of Reflex Klystron & derive power output & efficiency

Working principle of Reflex Klystron - 4

Derivation power output and Efficiency- 12

(OR)

b) A Reflex Klystron is operated at 5 GHz with an anode voltage 1000 V and the

cavity gap 2 mm. Calculate the gap transit angle. Find the optimum length of

the drift region. Assume N = 1¾ , V_R = -500 V.

12 a) Explain the working principle of TWTA in detail

Diagram 5

Construction and working principle – 11

(OR)

b) A Reflex Klystron is operated at 9 GHz with DC beam voltage

600 V for 1¾ mode, repeller space length 1 mm, DC beam current 10 mA.

The beam coupling co-efficient is assumed to be 1. Calculate the repeller

voltage, electronic efficiency and output power.

(a) Explain Magnetron & Derive for Hull cut off magnetic equation

Construction and working principle – 8

Derivation 8

(OR)

(b) Explain the working principle of Klystron Amplifier & derive power output & efficiency

working principle – 6

Derivation – 10

(a) Draw the Suitable diagram and explain the Fabrication process of Monolithic Microwave integrated circuits. Give examples for Fabrication

Epitaxial Growth

Oxidation

Diffusion

Isolation

Metallization

Packing

(OR)

(b) Draw and explain Micro strip lines also derive characteristic Impedance and Q

of micro strip lines

Strip line construction derivation for Characteristic Imp - 8

Micro Strip line construction derivation for Characteristic Imp - 8

i) Describe the four types materials used in MMIC fabrication (8)

Substrate Material, Conductor material, Resistive, Dielctric

ii) List the merits and demerits of planar transmission lines.(8)

Low cost , Less size, Low power

(OR)

(b) A micro strip line is composed of zero thickness copper conductor on a

substrate having relative dielectric constant of 8.4, dielectric loss tangent of

0.0005 and thickness of 2.4 mm.If the line width is 1 mm and operated at

10Ghz, calculate the characteristic impedance and the attenuation due to

conductor loss

SUBJECT : Microwave Engineering CODE : EC 1403

BRANCH : ECE SEM : VII

DURATION : 3 Hrs MAX MARKS : 100

NOTE: ANSWER ALL QUESTIONS

PART – A (10 X 2 = 20)

What do you mean by coplanar strip line

Parallel conductors in between a conducting strip

List the various types of striplines used in MMIC

Strip line, Microstrip line

What is the formula for cyclotron angular frequency

Wo/em

List the different types of Magnetrons

Negative Resistance magnetrons

Cyclotron frequency magnetron

Traveling wave magnetrons

List the advantages of Reflex klystron over multi-cavity klystrons

What is meant by velocity modulation?

The change in the velocity of the electrons under the influence of an alternating field is termed as velocity modulation

What is the maximum electronic efficiency of a Reflex klystron?

22.7

List out the different types of losses involved in micro strip lines

Dielectric loss , Ohmic Skin Loss, Radiation Loss

Write the Advantages of Micro strip lines

Low cost , Less size, Low power

Distinguish between strip line and micro strip line

Stripline - Parallel conductors in between a conducting strip

Micro stripline- in the dielectric substrate conducting strip

PART – B (5 X 16 = 80)

(a) Derive the expression for power output and efficiency of Cylindrical magnetron

Construction and working principle – 8

Derivation 8

(OR)

(b) Explain the working principle of TWTA in detail

Diagram 5

Construction and working principle – 11

12.(a) Explain the working principle of Reflex Klystron & derive power output &

efficiency

Working principle of Reflex Klystron - 4

Derivation power output and Efficiency- 12

(OR)

(b) Explain the working principle of Klystron Amplifier & derive power output

& efficiency

Working principle of Klystron Amplifier - 4

Derivation power output and Efficiency- 12

13. (a) A Reflex Klystron is operated at 5 GHz with an anode voltage 1000 V and

the cavity gap 2 mm. Calculate the gap transit angle. Find the optimum length

of the drift region. Assume N = 1¾ , V_R = -500 V.

(b) A lossless parallel strip line has a conducting strip width w. the substrate

dielectric separating the two conducting strips has a dielectric constant of 8,

a thickness d of 5mm and the characteristic impedance of 50 ohms

14. (a) Draw the Suitable diagram and explain the Fabrication process of Monolithic

Microwave integrated circuits. Give examples for Fabrication

Epitaxial Growth

Oxidation

Diffusion

Isolation

Metallization

Packing

(OR)

(b) Draw and explain Micro strip lines also derive characteristic Impedance and Q

of micro strip lines

Strip line construction derivation for Characteristic Imp - 8

Micro Strip line construction derivation for Characteristic Imp - 8

15. (a) A micro strip line is composed of zero thickness copper conductor on a

substrate having relative dielectric constant of 8.4, dielectric loss tangent of

0.0005 and thickness of 2.4 mm.If the line width is 1 mm and operated at

10Ghz, calculate the characteristic impedance and the attenuation due to

conductor loss

(OR)

(b)i) List out the basic materials required for the manufactured of MMIC

Substrate Material, Conductor material, Resistive, Dielctric

ii) Draw and explain Micro strip lines also derive characteristic Impedance and

Q of micro strip lines

Low cost , Less size, Low power

Microwave:Electronics & Communication Engineering 7th semester notes

2010-11-10T23:36:00.001-08:00

SUBJECT : Microwave Engineering CODE : EC 1403

BRANCH : ECE SEM : VII

DURATION : 3 Hrs MAX MARKS : 100

NOTE: ANSWER ALL QUESTIONS

SCHEME OF EVALUATION

PART – A (10 X 2 = 20)

1. Explain Unitary Property

The sum of products of each term of any one row or of any column of the s matrix multiplied its complex conjucate is unity.

2. What are the performance parameters of Directional Coupler

3. Why we need S matrix for microwave Analysis.

Suitable equipments are not available at microwave frequencies for the measurements of voltages and current at the ports of the networks

Short circuit and open circuit conditions are difficult at these frequencies.

Active devcies like power transistors, tunnel diodes etc don’t have suability under open /short circuit conditions.

4. Define Gunn Effect.

5.List out any two Non Reciprocal Devices.

(a) Isolator (b) Circulator

6. Why we cant use elemental based semiconductors in microwave

(a) Maximum Saturated Drift Velocity is Limited

(b) Applied Electric Field is also constant

7. Write the relation between S matrix and ABCD Matrix

S₁₁= A-B-C-D/A-B+C-D

S₂₂= -A-B-C-D/ A-B+C-D

S₁₂= -2(AD+BC)/ A-B+C-D

S₂₁= 2/ A-B+C-D

8. List out the various modes of Gunn Diode

Gunn oscillation mode, stable amplification mode, LSA oscillation mode and bias current osillation mode.

9. Write any four advantages of Parametric Up converter

Positive input impedance, Unconditionally stable, Unilateral and No circulator required

10. What is Avalanche Transit Time devices

Due to excess of charge carriers produced there is a delay in charge carriers moving

towards the other terminal of the diode. This effect is called avalanche time effect

PART B

11.

b) Explain about Four port circulator & obtain S-matrix of Three port circulator

Four port circulator Diagram - 4

Working Principle - 5

Three port circulator Derivation - 7

S = 0 0 1

1 0 0

0 1 0

12. ) a) Derive and Explain Magic Tee.

S14=S41=S24=S42

S31=S13=-S23=-S32

S34=S43=0

S12=S21=0

S= 0 0 1/√2 1/√2

0 0 -1/√2 1/√2

1/√2 -1/√2 0 0

1/√2 1/√2 0 0 - 16

(OR)

b) Briefly explain Hybrid couplers and Rings also derive the S matrix for that.

Hybrid couplers diagram and working principle - 4

S matrix for Hybrid couplers -4

Hybrid Rings diagram and working principle -4

S matrix for Hybrid Rings -4

13. a)Derive and explain Two Hole Directional coupler in detail

Performance characteristics of Directional coupler -4

S matrix derivation - 12

(OR)

b) Explain Gunn effect, RWH Theory, high field domain & Two valley model theory in details

RWH Theory: Voltage controlled Mode with diagram

Current controlled mode with diagram – 7

Two valley model Theory : Diagram

Energy separation between valleys - 5

14. a) Briefly explain the operation and working principles of READ diode

Physical Description - 4

Avalanche Multiplication - 4

Carrier current I_o(t) and External current I_e(t) - 4

Output Power and Quality Factor - 4

(OR)

(b) Write short notes on (1) CdTe diodes (2) InP diodes

CdTe diodes construction and working principle - 8

InP diodes construction and working principle - 8

15. (a) Explain Manley Rowe Power relation also discuss any two applications of Parametric Amplifiers

Diagram -4

Parametric amplifiers - 4

Parametric Up Converter -4

Parametric Down Converter - 4

(OR)

b) Write short notes on Microwave Amplification and Generation

Microwave Amplification - 8

Microwave Generation - 8

Optical communication:Electronics & Communication Engineering 7th semester notes

2010-11-10T23:33:00.000-08:00

SUBJECT/CODE:EC1402 : OPTICAL COMMUNICATION BRANCH:VII-SEM-ECE

DURATION : 3hrs. MAX.MARKS:100

MODEL EXAMINATION-III OCT.2010

ANSWER ALL QUESTIONS

PART-A 10X2 = 20Marks

1. Give the refractive index expression of a graded index fiber.

n ( r ) = n₁[ 1-2Δ(r/a)^α]^1/2 for 0≤ r ≤a

= n₁[ 1-2Δ]^1/2 = n₁[ 1 - Δ] = n₂ for r ≥ a

2. A point source of light if 12 cm below the surface of a large body of water (n=1.33). What is the radius of the largest circle on the water surface through which the light can emerge?

Find θc from Snell's law
n1*sinθ1=n2*sinθ2=1
n2=1.33
then θc=48.75 degree
Find r from tan θc= r / 12cm
r =13.7 cm.

3. Give the expression of the effective number of modes that are guided by a curved multimode fiber of radius ‘a’.

N_eff= N_∞{ 1- (α+2)/(2αΔ)[(2a/R)+(3/2n_cladkR)^2/3]}

Where α defines the graded index profile

Δ is the core-cladding index difference, k is the propagation constant

R is the radius of the curvature of the bent fiber.

a is the fiber core radius

N_∞ is the total number modes in straight fiber.

4. Define normalized propagation constant.

Normalized propagation constant is defined by

b = {β²/k²-n²_clad}/ {n²_core - n²_clad }

Where k is propagation constant

5. An LED has radiative and non radiative recombination times of 30 and 100ns respectively. Determine the internal quantum efficiency.

The internal quantum efficiency in the active region is the fraction of electron hole pairs that recombine radiatively. It’s given by

η_i=R_r/ (R_r+ R_nr)

η_i is the internal quantum efficiency

R_ris the radiative recombination per unit volume.

R_nr is the non radiative recombination rate

6. Define internal quantum efficiency of a LED.

The internal quantum efficiency in the active region is the fraction of electron hole pairs that recombine radiatively. It’s given by

η_i=R_r/ (R_r+ R_nr)

η_i is the internal quantum efficiency

R_ris the radiative recombination per unit volume.

R_nr is the non radiative recombination rate

7. An APD generates a current of 100nA when the incident power is 5nW. The operating wavelength is 1.5 µm. Find its responsivity. If the quantum efficiency is 0.7, find the multiplication factor.

I_p= RP_o = (ηq/hv) P_o

= (ηqλ/hc) P_o

= {(0.7)(1.6 x 10^-19)(1.5 x 10^-6)/(6.625 x 10^-34 x 3 x 10⁸)}5 x 10^-9

= 4.263nA

The multiplication factor(M) = I_m / Ip = 100nA/4.263nA = 23.46

8. Define Responsivity.

R = I_p/P₀ = ηq/hν where I_p-average photocurrent generated

P_0- incident optical power level

η -quantum efficiency

9. What are solitons?

The term “Soliton” refers to special kinds of waves that can propagate undistorted over long distances and remain after collisions with each other. John Scott Russell made the first recorded observation of a soliton in 1838,when he saw a peculiar type of wave generated by boats in narrow Scottish canals.

In optical communication systems, solitons are very narrow, high-intensity optical pulses that retain their shape through the interaction of balancing pulse dispersion with the nonlinear properties of an optical fiber.

The set of pulses that do not change in shape are called fundamental solitons, and those that undergo periodic shape changes are called higher-order solitons.

10. What is the significance of rise time budget?

A rise time budget analysis is a convenient method for determining the dispersion limitation of an optical fiber link

t_{sys =}(t_tx²+ t_mod²+ t_mat ²+ t_rx²)^1/2

PART-B(16x5 = 80)

11. a. (i) Derive an expression for numerical aperture of a step index fiber(10)

(ii) The relative refractive index difference between the core axis and the cladding of a guided index fiber is 0.7% when the refractive index at the core axis 1.45. Estimate values for the numerical aperture of the fiber along the axis when the index profile is assumed to be triangular.(6)

a. i. NA = nsinθ_0,max = sqrt(n₁² – n₂² ) = n₁ sqrt(2Δ)

b. Discuss the theory of graded index fibers. Derive the expression for numerical

aperture of graded index fiber.(16)

Refer Page No. from 65 to 66 (in Keiser)

n ( r ) = n₁[ 1-2Δ(r/a)^α]^1/2 for 0≤ r ≤a

= n₁[ 1-2Δ]^1/2 = n₁[ 1 - Δ] = n₂ for r ≥ a

NA( r ) = NA(0) [1-(r/a)^α]^1/2 for r ≤a

= 0 for r > a

12.a. Explain with suitable diagrams the different mechanism that contribute to

attenuation in optical fiber. (16)

Absorption (4)

Scattering (4)

Bending (4)

Core and cladding (4)

Refer Page No. from 94 to 103 (in Keiser)

b. i) A continuous 40-km-long optical fiber link has a loss of 0.4 dB/Km

(a) What is the minimum optical power level that must be launched into the

fiber to maintain an optical power level of 2 mw at the receiving end?

(b) What is the required input power if the fiber has a loss of o.6 db/km

ii) What is meant by waveguide dispersion? Derive the expression (8)

Refer Page No. from 109 to 111 (in Keiser)

13.a. Explain briefly the three key processes involved in the laser action. Describe for a fabry

perot resonator laser diode, modes and threshold conditions. Obtain its rate equations for

steady state output. (16)

Refer Page No. from 163 to 171 (in Keiser)

b. (i) Discuss the different misalignment losses and their magnitudes.(8)

Refer Page No. from 218 to 223 (in Keiser)

(ii)A step-index fiber has a core refractive index 1.5 and a core diameter of 50μm

The fiber is joined with a lateral misalignment between the core axes of 5μm.

Estimate the lateral efficiency and the insertion loss at the joint due to lateral

misalignment.(8)

14.a. With neat diagram explain operation and characteristics of PIN photodiode.

(16)

Refer Page No. from 244 to 248 (in Keiser)

b. (i) A silicon PIN photodiode incorporated into an optical receiver has a quantum efficiency of 60% at a wavelength of 0.9μm. The dark current is 3nA and load resistance is 4kΩ. The incident optical power is 200nW and the receiver bandwidth is 5MHz. Determine

1. Mean square quantum noise current.

2. Mean square dark current

3. Mean square thermal noise current at a temperature of 20ºC.(8)

(ii) The quantum efficiency of particular silicon RAPD is 80% for the detection

of radiation at a wavelength of 0.9μm, when the incident optical power is

0.5μW. The output current from the device (after avalanche gain) is 11μA.

Determine the multiplication factor of the photodiode under these conditions.

15.a Explain briefly link power budget and rise time budget analysis in optical

communication system. (16)

Refer Page No. from 325 to 330 (in Keiser)

b. Explain the salient features of solitons using relevant expressions and diagrams.(16)

Refer Page No. from 506 to 510 (in Keiser)

SUBJECT/CODE:EC1402 : OPTICAL COMMUNICATION BRANCH:VII-SEM-ECE

DURATION : 3hrs. MAX.MARKS:100

ANSWER ALL QUESTIONS

PART-A 10X2 = 20Marks

1. Define acceptance angle and critical angle of the fiber.

If the angle of incidence Φ₁ is increased a point will eventually be reached where the light ray in air is parallel to the glass surface. This point is known as critical angle of incidence Φc.

2. Calculate the number of modes in the graded index fiber at an operating wavelength of 850nm.

3. What is the need for mode coupling in optical fiber?

Coupling energy from one mode to another is called mode coupling. It arises because of structural imperfections, fiber diameter and refractive index variations and cabling induced in micro bends.

4. Define Group delay.

It is defined as the ratio of distance travelled by pulse to the group velocity,

τ_g = L/V_g

5. What is meant by indirect band gap?

In indirect band gap materials direct transition is not possible from valence band to conduction. e.g.silicon, germanium.

6. Define quantum efficiency of an LED.

The internal quantum efficiency in the active region is the fraction of electron hole pairs that recombine radiatively. It’s given by

η_i=R_r/ (R_r+ R_nr)

η_i is the internal quantum efficiency

R_ris the radiative recombination per unit volume.

R_nr is the non radiative recombination rate

7. Define Quantum Limit.

It is possible to find the minimum received optical power required for a specific bit error rate performance in a digital system. This minimum received power level is known as quantum limit.

8. What are the benefits of transimpedance amplifier?

Since the high impedance produces large input RC time constant, the front end bandwidth is less than the signal bandwidth. This drawback is overcome in the trans impedance preamplifier

9. What is the purpose of rise time budget analysis?

A rise time budget analysis is a convenient method for determining the dispersion limitation of an optical fiber link

t_{sys =}(t_tx²+ t_mod²+ t_mat ²+ t_rx²)^1/2

10. What is meant by Solitons?

The set of pulses that do not change in shape are called fundamental solitons, and those that undergo periodic shape changes are called higher-order solitons.

PART-B (5x16=80)Marks

11.(a) Derive an expression to determine the modes propagation in Step Index fiber.(16)

[OR]

(b)(i) Explain with neat block diagram the fundamentals of optical fiber

Communication (8)

(ii) Discuss the propagation of meridional rays along with the acceptance angle and

numerical aperture of step index fiber. (8)

12.(a) Explain with suitable diagrams the different mechanism that contribute to

attenuation in optical fiber. (16)

[OR]

(b)Write a brief note on design optimization with relevant expression and diagram(16)

13.(a) Explain the basic LED configuration used as optical source. Derive the expression

for quantum efficiency and optical power generated in LEDs. (16)

[OR]

(b)(i) Explain the steps involved in splicing the fiber. Discuss the various splicing

techniques employed between 2 fibers. (8)

(ii) Explain the lensing scheme used to improve optical source to fiber coupling

efficiency. (8)

14.(a) With neat diagram explain operation and characteristics of PIN photodiode. (16)

[OR]

(b)(i) Draw and explain high impedance preamplifier design based on BJT and FET.(8)

(ii) Write a brief note on transimpedance amplifier (8)

15.(a) Explain briefly link power budget and rise time budget analysis in optical

communication system. (16)

[OR]

(b)(i)Explain the principle of WDM? (8)

(ii)Explain the basic concept of SONET Network. (8)

SUBJECT/CODE:EC1402 : OPTICAL COMMUNICATION BRANCH:VII-SEM-ECE

DURATION : 3hrs. MAX.MARKS:100

MODEL EXAMINATION-III OCT.2010

ANSWER ALL QUESTIONS

PART-A 10X2 = 20Marks

1. What are the linearly polarized modes?

These modes are having same electric field patterm and the propagation constant and the modes are said to be degenerate. The degenerate modes are called linearly polarized modes.

2. Calculate the numerical aperture of a step index fiber having n1 = 1.48 and n2 = 1.46.

NA=√ n₁² – n₂²

3. What is meant by Polarization Mode Dispersion?

The difference in propagation times between two orthogonal polarization modes will results in pulse spreading. This is PMD.

4. What is intermodal dispersion? What does it cause?

Intermodal dispersion is pulse spreading that occurs within a single mode. It arises due to group velocity being a function of wavelength. The increasing spectral width of the optical source will increase the intramodal dispersion.

5. What is population Inversion?

Stimulated emission will exceed absorption only if the population of the excited status is greater than that of the ground state. This condition is known as population inversion.

6. Compare LED and LASER Diode.

LED: 1. Optical output is incoherent.2. Output radiation has a broad spectral width.

LASER: 1.Optical output is coherent 2. very directional.

7. Define Quantum efficiency and responsivity of photo detector.

Quantum efficiency is defined as the number of electron hole pair generated per incident photon of energy and responsivity is defined as the ratio of output photocurrent to the incident optical power.

8. Compare the performance of APD and PIN Diode.

PIN:1. Sensivity: less sensitive 2. Gain : no internal gain

APD: 1. more sensitive 2. internal gain

9. Define Modal Noise.

Modal noise arises when the light from a coherent lase is coupled into a multimode fiber.

10. What are the advantage of WDM?

1. capacity upgrade

2. transparency

PART-B (5x16=80)Marks

11.(a) (i)Derive the wave equation in Step Index fiber. (12)

(ii) Mention the advantage of optical fiber communication system (4)

[OR]

(b)(i) Discuss briefly about Linearly polarized mode. (8)

(ii)Draw the structure of single and multimode step index fiber and graded index

fiber with their typical dimension . (8)

12.(a) Discuss material and waveguide dispersion mechanisms with necessary mathematical

expressions. (16)

[OR]

(b)(i)Explain the scattering and bending losses that occur in an optical fiber with

relevant diagrams and expressions. (8)

(ii)Discuss polarization mode dispersion and its limitations. (8)

13.(a)(i) Draw and explain the different structure used to achieve carrier and optical

confinement in laser diodes. (10)

(ii) Explain the modulation process involved in LED and discuss its frequency

response. (6)

[OR]

(b)(i) Derive an expression for the power coupled from a surface emitting LED into step

index and graded index fibers. (10)

(ii) Explain mechanical misalignment that can occur between 2 joined fibers with

necessary diagrams. (6)

14.(a)With neat diagram explain operation and characteristics of avalanche photodiode. (16)

[OR]

(b)(i) Discuss with necessary expressions the different types of noise that affect the

performance of a photodetector. (10)

(ii) Write a brief note on transimpedance amplifier (6)

15.(a) (i)What are the system consideration in point to point links? Explain in detail. (10)

(ii) Explain the link power budget in optical communication system. (6)

[OR]

(b)Explain the salient features of solitons using relevant expression and diagrams. (16)

Optical communication:Electronics & Communication Engineering 7th semester notes

2010-11-10T23:31:00.000-08:00

Optical communication

Sub.Name/Code:EC1402:Optical Communication Max.Marks:100

Branch : B.E (ECE) SEM :VII

Answer all the questions

PART-A (10x2 = 20M)

1. Mention any four required properties of light sources used in the optical communication.

· High radiance output

· Fast emission response time

· High quantum efficiency

· Dimensional characteristics compatible with those of optical fibers.

2. What is meant by laser action? What are the conditions to achieve it?

Laser action is the result of three key processes

1. Photon absorption

2. Spontaneous emission

3. Stimulated emission

The conditions to achieve laser action are

1. Magnitude of guided mode should be greater than the threshold value.

2. At the lasing threshold, a steady state oscillation takes place, and the

magnitude and phase of the returned wave must be equal to those of the

original wave.

3. What are direct band gap and indirect band semiconductors?

In direct band gap materials direct transition is possible from valence band to conduction band. e.g.GaAs, InP, InGaAs

In indirect band gap materials direct transition is not possible from valence band to conduction. e.g.silicon, germanium

4. Define internal quantum efficiency of a LED.

The internal quantum efficiency in the active region is the fraction of electron hole pairs that recombine radiatively. It’s given by

η_i=R_r/ (R_r+ R_nr)

η_i is the internal quantum efficiency

R_ris the radiative recombination per unit volume.

R_nr is the non radiative recombination rate

5. An LED has radiative and non radiative recombination times of 30 and 100ns respectively. Determine the internal quantum efficiency.

6. What are the required properties of photo detector?

1. High response or Sensitivity

2. Minimum addition of noise

3. Fast response speed

4. Insensitive to variations in temperature

5. Compatibility with physical dimensions of fiber.

6. Long operating life.

7. Reasonable cost.

7. An APD generates a current of 100nA when the incident power is 5nW. The operating wavelength is 1.5 µm. Find its responsivity. If the

quantum efficiency is 0.7, find the multiplication factor.

I_p= RP_o = (ηq/hv) P_o

= (ηqλ/hc) P_o

= {(0.7)(1.6 x 10^-19)(1.5 x 10^-6)/(6.625 x 10^-34 x 3 x 10⁸)}5 x 10^-9

= 4.263nA

The multiplication factor(M) = I_m / Ip = 100nA/4.263nA = 23.46

8. Define quantum efficiency of photo detector.

It is defined as the number of the electron – hole pairs generated per incident photon of energy hv.

9. Why do we prefer trans-impedance preamplifier rather than high impedance preamplifier?

Since the high impedance produces large input RC time constant, the front end bandwidth is less than the signal bandwidth. This drawback is overcome in the trans impedance preamplifier.

10. Define quantum limit.

It is possible to find the minimum received optical power required for a specific bit error rate performance in a digital system. This minimum received power level is known as quantum limit.

PART-B (16x5=80M)

11. a. (i) Draw a typical double-hetero structure light emitter and explain (8)

(ii)Draw the schematic of surface emitting and edge emitting LED and explain (8)

b. (i) Derive the threshold condition for lasing (6)

(ii) Explain the laser action with neat diagrams (6)

(iii) A GaAs laser operating at 850nm has a 500μm length and a refractive index n=3.7.What are the

frequency and wavelength spacing? (4)

12. a. (i) Derive the internal quantum efficiency of an LED (6)

(ii) Discuss laser diode structures and radiation patterns (10)

b. (i) What is quantum well laser? Explain its geometry and features (6)

(ii) Discuss the temperature effect on threshold current of a laser diode (6)

(iii) A GaAs injection laser with a cavity length of 500μm has a loss co-efficient of 20 cm. the measured differential external

quantum efficiency of laser is 45,the refractive index of GaAs 3.6.calculate the internal quantum efficiency of the laser. (4)

13. a. (i) Explain various fiber splicing techniques and their merits and demerits. (10)

(ii) Explain the different splice losses and their measurement (6)

b. (i) Draw the structure of avalanche photodiode and electric fields in the depletion and multiplication regions.

Also explain the principle of operation of APD.(8)

(ii) A given silicon avalanche photodiode has a quantum efficiency of 65% at a wavelength of 900nm.If 0.5μW

of optical power produces a multiplied photo current of 10 μA, find the multiplication factor (M). (8)

14. a. (i) Discuss the different noise sources and disturbances in the optical pulse detection mechanism.(6)

(ii) Derive an expression for the bit error rate of an optical digital receiver.(10)

b. (i) Draw and explain the high impedance preamplifier designs based on BJT and FET.(8)

(ii) Write a brief note on trans impedance amplifier.(8)

15. a. Discuss in detail digital receiver performance calculation and sensitivity calculation in detail (16)

b. (i) Describe the construction and working of PIN diode (10)

(ii) When 3x10¹¹photons each with a wavelength & 0.5 μm are incident an a photo diode , on average 1.2x10¹¹electrons are

collected at the terminals at the device.Determine the quantum efficiency and the responsivity of the photo diode at

0.85 μm (6)

Sub.Name/Code:EC1402:Optical Communication Max.Marks:100

Branch : B.E (ECE) SEM :VII

Answer all the questions

PART-A (10x2 = 20M)

1. What are the laser light properties? How are they produced

a. High radiance output

b. Fast emission response time

c. High quantum efficiency

d. Dimensional characteristics compatible with those of optical fibers.

High radiance and high quantum efficiency are achieved through carrier and optical confinement using double hetero structure.

2. Why do we prefer laser diodes over LED’s for communication applications?

1. High intensity radiation

2. Narrow spectral width of the laser source are the preferable features of

Laser compared to LED.

3. What are direct band gap semiconductors?

In direct band gap materials direct transition is possible from valence band to conduction band. e.g.GaAs, InP, InGaAs

4. Explain the radiation pattern from surface emitting laser diode or LED

The emission pattern is isotropic with a 120 degree half-power beam width, i.e., source is equally bright when viewed from any direction, but the power diminishes as cosθ, where θ is the angle between the viewing direction and normal to the surface.

5. Distinguish between splice and connector.

SPLICE	CONNECTOR
1. A permanent joint formed between two individual optical fibers in the field or factory.	In order to maintain an optimum performance the connection must also protect the fiber ends from damage which may occur due to handling(connection and disconnection), must be insensitive to environmental factors(e.g. moisture and dust) and cope with tensile load on the cable.
2. It is used to establish long-haul optical fiber links where smaller fiber lengths need to be joined, and there is no requirement for repeated connection and disconnection.	The connector design must allow for repeated connection and disconnection without problems of fiber alignment, which may lead to degradation in the performance of the transmission line at the joint.
3.Two types-Fusion splicing and Mechanical splicing.

6. What is dark current noise?

The dark current noise arises from electrons and/or holes which are thermally generated in the PN junction of the photo diode. This current continues to flow through the bias circuit of the device when no light is incident on the photodiode

7. What are the different factors that determine the response time of photo detector?

i. The transit time of the photo carriers in the depletion region.

ii. The diffusion time of the photo carriers generated outside the depletion region.

iii. The RC time constant of the photodiode and its associated circuit.

8. Define probability of error. Write an expression for it.

The probability of error is defined as P_e = a P₁(v_th) + bP₀(v_th)

Where a and b are weighting factors

P₁(v_th) – Probability that the equalizer output voltage is less than v_th when a logical one pulse is sent.

P₀(v_th) - Probability that the equalizer output voltage exceeds v_th when a logical zero pulse is transmitted.

9. A given APD has a quantum efficiency of 65%at a wavelength 900nm. If 0.5 μW of optical power produces a multiplied photocurrent of 10 μA, find the multiplication factor

I_p= RP_o = (ηq/hv) P_o = (ηqλ/hc) P_o

= {(0.65)(1.6 x 10^-19)(9 x 10^-7)/(6.625 x 10^-34 x 3 x 10⁸)}5 x 10^-7

= 0.235μA

The multiplication factor(M) = I_m / Ip = 10μA/0.235μA = 43

10. Compare the performance of APD and PIN diode

The avalanche photodiode (APD), is also reverse-biased. The difference with the PIN diode is that the absorption of a photon of incoming light may set off an electron-hole pair avalanche breakdown, creating up to 100 more electron-hole pairs. This feature gives the APD high sensitivity (much greater than the PIN diode).

PART-B (16x5=80M)

11. a. (i) Draw a typical double-hetero structure light emitter and explain (8)

(ii)Draw the schematic of surface emitting and edge emitting LED and explain (8)

b. Discuss different types of fiber optic amplifiers and also compare their properties. (16)

12.a. (i) Explain various fiber splicing techniques and their merits and demerits. (10)

(ii) Explain the different splice losses and their measurement (6)

b. (i) Explain the different factors affecting the source to fiber power launching(8)

(ii) Estimate the power delivered to different types of fibers with respect to LEDs(8)

13.a. (i) Draw and explain the different structures used to achieve carrier and optical confinement in laser diodes.(10)

(ii) Discuss the effects of temperature on the performance of a laser diode. (6)

b.Describe briefly the construction and working and characteristics of PIN diode (16)

14. a.(i)Explain the different types of noise that affect the performance of a photodetector(10)

(ii)When 3x10¹¹photons each with a wavelength & 0.5 μm are incident an a photo diode , on average 1.2x10¹¹electrons

are collected at the terminals at the device. Determine the quantum efficiency and the responsivity of the photo diode

at 0.85 μm (6)

b. Discuss in detail digital receiver performance calculation and sensitivity calculation in detail (16)

15.a. (i) Discuss the different noise sources and disturbances in the optical pulse detection mechanism.(6)

(ii) Derive an expression for the bit error rate of an optical digital receiver.(10)

b. What is the role of preamplifier in optical receiver? Explain in brief different types of preamplifier available? (16)

TQM:Electronics & Communication Engineering 7th semester notes

2010-11-10T23:28:00.001-08:00

SUBJECT: MG 1401-TOTAL QUALITY MANAGEMENT

SET-3

PART-A

1] Define quality.

A] Fitness for intended use; Conformance to specifications; Meeting or exceeding customer expectations, etc.

2] What do you understand by quality statement?

A] It includes the vision, mission, and quality policy statements. They are part of the strategic planning process.

3] What is cross functional team?

4] Expand 5S.

A] Seiri, Seiton, Seiso, Seiketsu, and Shitsuke.

5] List out various measures of dispersion in SPC.

A] Range, Standard Deviation, and Variance.

6] What is Six Sigma?

7] What is Kaizen?

8] What is Taguchi Quality Loss Function?

9] What are the objectives of TPM?

A] Maintaining equipment for life; maintaining and improving equipment capacity; using support from all areas of operation; encouraging inputs from all employees.

10] What is the need for quality systems in an organization?

A] They promote the growth of international trade by facilitating harmonious interactions between suppliers and customers located in diverse locations globally.

PART-B

11[a] List out the barriers to TQM implementation.

11[b] Discuss the dimensions of quality with examples.

12[a] Explain the actions that an organization should take to handle customer complaints.

12[b] Explain the importance of customer satisfaction.

13[a] Explain the different types of control charts used for problem solving.

13[b] Explain the use of the seven new management tools for managing quality.

14[a] Explain the QFD process in detail.

14[b] Explain the different steps involved in FMEA.

15[a] Discuss the method of conducting quality audit for ISO 9000 certification.

15[b] Explain the requirements of Environmental Management Systems.

TQM:Electronics & Communication Engineering 7th semester notes

2010-11-10T23:27:00.001-08:00

SUBJECT: MG 1401-TOTAL QUALITY MANAGEMENT

SET-2

PART-A

1] What do you mean by the term ‘Cost of Quality’?

A] Quality costs are the costs associated with monitoring, ensuring or failing to achieve product/service quality. They are classified as prevention costs, appraisal costs, internal failure costs, and external failure costs.

2] What are the elements of TQM?

A] Top management commitment, customer focus, employee involvement, etc.

3] What is customer satisfaction?

A] Meeting or exceeding customer expectations in the use of a product/service.

4] List the benefits of team work.

A] Many heads are more knowledgeable than one. Each member of the team has special abilities that can be used to solve problems. It promotes camaraderie, team spirit.

5] Distinguish between discrete and variable data with suitable examples.

A] Variable data occur on a continuous scale, e.g. length, diameter, weight, temperature, etc. Discrete data can be counted or classified as good or bad, e.g. number of errors, good quality or poor quality, etc.

6] What is the need for six sigma state?

7] What is Benchmarking?

A] Benchmarking is a systematic method by which organizations can measure themselves against the best industry practices and implement changes to gain competitive advantage.

8] Give Taguchi’s definition of Quality.

9] What are the ISO 9000 standards?

A] ISO 9000 is a quality management system (QMS), i.e. a se of quality standards aimed at promoting the growth of international trade by facilitating harmonious interactions between suppliers and customers located in diverse locations globally.

10] Mention the objectives of Quality audits.

A] To determine whether quality activities and results comply with planned arrangements, whether these arrangements are implemented effectively, and whether these are suitable to achieve objectives.

PART-B

11[a] Explain in detail the road map of quality planning.

A] Explain various aspects such as vision statement, mission statement, quality policy, strategic plan, quality plan, procedures, etc. in detail.

11[b](i) Explain the basic concepts of TQM.

A] Explain the following: top management commitment, customer focus, worker involvement, continuous improvement, treating suppliers as partners, performance measures, etc.

11[b](ii) Explain the principles of TQM.

A] Explain the following: People and relationships – leadership, customer satisfaction employee involvement, supplier partnership, etc.

12[a](i) Describe the importance of customer retention in an organization.

A] Explain aspects like customer focus, customer satisfaction, customer loyalty, customer retention, etc.

12[a](ii) Discuss Maslow’s hierarchy of needs.

A] Explain the five levels of needs propounded by Maslow: Physiological needs, security needs, social needs, esteem needs, and self-actualization needs.

12[b] Explain all the elements of 5S principles in detail.

A] Explain the features and importance of each of the 5S: Seiri, Seiton, Seiso, Seiketsu, and Shitsuke.

13[a] Explain with neat diagrams and examples, the seven tools of quality.

A] Explain the features and usage of the following: check sheet, histogram, scatter diagram, control chart, Pareto chart, cause-and-effect diagram, and process decision program chart.

13[b](i) Cricket scores problem:

A] Average scores: Batsman A = 542/11 = 49.27; Batsman B = 604/11 = 54.91

Standard deviations: Batsman A = √(12,867/11) = 34.2; Batsman B = √(8,381/11) = 27.6

Batsman B is both the better scorer and the more consistent scorer.

13[b](ii) Describe in detail the steps of achieving the six sigma state.

A] Explain the DMAIC and DMADV models of six sigma implementation.

14[a](i) Explain each section of the basic structure of ‘House of Quality’.

A] Explain the nine parts comprising the HOQ: customer requirements (whats); technical requirements (hows); interrelationships among the ‘hows’; relationships between the ‘whats’ and the ‘hows’; importance ratings; competitors’ evaluation; selling points; targets; and deployment.

14[a](ii) Highlight the benefits of QFD.

A] Briefly explain the following: reduces product development time and costs; reduces time to market; improves customer satisfaction; improves quality; reduces quality costs.

14[b](i) Explain the objectives and concept of TPM.

A] Explain the importance of TPM and the various objectives it aims to achieve in improving an organization’s functioning.

14[b](ii) List the benefits of FMEA.

A] Explain FMEA as a tool to foresee and prevent at the design stage itself all possible ways in which a product can fail during its use and the various benefits of taking such advance preventive action.

15[a] Explain the classification of ISO 9000 quality system standards.

A] Explain the relevant features of ISO 9001, ISO 9002, ISO 9003 and ISO 9004.

15[b] Explain the steps involved in the implementation of Quality system.

A] Explain the 15 steps involved, viz. top management commitment, appoint management representative, awareness program, implementation team, training, time schedule, etc.

TQM:Electronics & Communication Engineering 7th semester notes

2010-11-10T23:26:00.002-08:00

SUBJECT: MG 1401-TOTAL QUALITY MANAGEMENT

SET-1

PART-A

1] What are the dimensions of quality?

A] Dimensions of product quality: Performance, features, usability, conformance, reliability, durability, maintainability, efficiency, aesthetics, and safety.

Dimensions of service quality: Time, timeliness, completeness, consistency, convenience, accuracy, responsiveness, courtesy, and competency/expertise.

2] Define the term Appraisal Cost.

A] The costs incurred in assessing the quality of output at various stages of production.

3] Differentiate between Recognition and Reward.

A] Recognition is publicly acknowledging the contributions made by an employee in achieving an organization’s objectives. Reward takes the form of monetary and non-monetary incentives in the form of cash gift, prize, promotion, etc.

4] Define Empowerment.

A] Empowerment is the power and authority given to an employee to show initiative and take decisions on his own without the need to consult his superior.

5] What are the new management tools of quality?

A] (i) Affinity diagram, (ii) Relationship diagram, (iii) Tree diagram, (iv)Matrix diagram, (v) Prioritization matrix, (vi) Process decision program chart, and (vii) Activity network diagram.

6] Define process capability ratio.

A] The ratio of the specification width to the natural control limits of a process.

C_P = (USL – LSL)/6σ where USL=upper specification limit, LSL=lower specification limit and σ = standard deviation.

7] What is QFD?

A] QFD is a method for developing a design quality aimed at satisfying the customer by integrating the voice of the customer (VOC) throughout the organization.

8] Name the pillars of TPM.

A] 1. 5S principles, 2. Jishu Hozen, 3. Kobetsu Kaizen, 4. Planned maintenance, 5. Quality Maintaenance, 6. Training, 7. Office TPM, and 8. Safety, health and environment.

9] Differentiate QMS and EMS.

A] QMS is Quality Management System, employed for achieving ISO 9000 standard while EMS is Environment Management System, employed for achieving ISO 14000.

10] What are the stages of audit?

A] 1.Audit planning, 2.Performance, 3.Reporting, and 4.Follow-up.

PART-B

11[a] [i] Explain the basic principles of TQM.

A] Explain each of the following: Management commitment; Focus on customer; Employee involvement; Continuous improvement; Treating suppliers as partners, etc.

11[a][ii] Discuss the barriers to TQM implementation.

A] Explain the following: Lack of management commitment,; Inability to change organizational culture; Improper planning; Lack of employee involvement, etc.

11[b] Explain Deming’s 14 philosophy.

A] Give brief explanations of Deming’s 14 Points, viz. 1. Create and publicize to all employees the aims and purposes of the organization, 2. Adopt the new philosophy, etc.

12[a] Define Teams. What are the various types of teams? Explain their roles and functions.

A] A team is defined as a group of people working together to attain common objectives. The various types of teams are: Quality Circles, Process improvement teams, Cross-functional teams, Problem-solving teams, Project teams, Self-directed teams, etc. (Give an explanation of their roles and functions).

12[b] Write short notes:

a) Juran Trilogy: Give explanations of [i] Quality planning, [ii] Quality control, and [iii] Quality improvement.

b) PDSA cycle: Give explanation of Deming’s Plan-Do-Study-Act cycle.

c) Kaizen: Explain the concept of gradual, continuous improvement.

d) 5’S concept: Explain the meanings of Seiri, Seiton, Seiso, Seiketsu, and Shitsuke.

13[a] Control charts problem:

A] X double bar = 51.35; R bar = 3.1

UCL (X bar) = 51.35 + (0.73)(3.1) = 53.61; LCL (X bar) = 51.35 – (0.73)(3.1) = 51.12

UCL (R) = D4.R bar = (2.28)(3.1) = 7.07; LCL(R) = 0

R-chart: process is in control; X bar chart: Sample 7 is outside control limits.

σ = R bar / d₂ = 3.1/2.059 = 1.506

C_P = (USL – LSL}/6σ = (54 – 46)/(6X1.506) = 0.885.

Since C_P < 1, machine is not capable of meeting specification requirements.

13[b] Explain the DMAIC and DMADV models of six sigma.

A] Explain the two basic models for implementation of six sigma: Define-Measure-Analyze-Improve-Control (DMAIC) model for improving existing processes, and Define-Measure-Analyze-Design-Verify (DMADV) model for designing new products.

14[a] Define Benchmarking. Discuss the types and steps in benchmarking process.

A] Give the definition of benchmarking, explain the types of benchmarking (internal, competitive, and process benchmarking), and discuss the six steps involved in the benchmarking process (Decide what to benchmark, Understand current performance, Plan, Study others, Learn from the data, and Use the findings).

14[b] Explain the House of Quality matrix and its components with an example.

A] Explain about QFD, discuss about the use of HOQ as a tool for implementing QFD, and explain the six components of the House of Quality through any example.

15[a] Write short notes on

(I) Policy, procedure, work instruction, records in ISO 9000: Give brief explanations of each of these terms as used in ISO 9000.

(II) Quality auditing Give the definition of the term, explain the stages in conducting quality audit, and the checklists for conducting audit.

DIP:Electronics & Communication Engineering 7th semester notes

2010-11-10T23:26:00.000-08:00

DIP

EC1009 - Digital Image processing

Part A

1. What is false contouring?

In an image, preserving the spatial resolution constant and reducing the number of

gray levels produces a fine ridge like structures in the smooth areas. This effect is caused

by the use of insufficient gray levels is called as false contouring.

2. State 1 D Hadamard transforms.

The Walsh transform is defined by

Where --------------1-D forward Hadamard Kernel

3. What is the principle of sharpening filters?

The principle objective of sharpening is to highlight the fine details in an image or

to enhance detail that has been blurred either in error or in image acquistition,

4. What is contrast stretching?

Contrast stretching reduces an image of higher contrast than the original by

darkening the levels below m and brightening the levels above m in the image.

5. List the advantages of interactive restoration.

The observer can control the restoration process by tuning the available

Parameters and able to obtain a final result that may be quite adequate for a special

purpose.

6. Why geometric transformation is called rubber sheet transformation?

Geometric transformation is applied to a image to modify the spatial relationship

between the pixels and to restore the image. It is called as rubber sheet transformation

because it may be viewed as printing the image on a sheet of rubber and then stretching

this sheet to some predefined set of rules.

7. What is inter frame redundancy?

It is directly related to the inter pixel correlations within a image. Because the

value of any given pixel can be predicted from the values of its neighbor, the visual

information carried by the individual pixel is relatively small.

8. Write the equation for the fidelity criteria for an image?

A closely related objective fidelity criterion is the mean square signal to the noise

ratio of the compressed - decompressed image.

9. List the problems associated with region growing.

Descriptors alone for region growing can yield misleading results if connectivity

or adjacency information is not used.Another problem with the region growing is the formulation of stopping rule.

10 How normalization can be done for chain code?

The chain code can be normalized with respect to the starting point is that a chain

code can be represented as a circular sequence of direction numbers and redefine the

starting point so that resulting sequence of numbers forms an integer of minimum

magnitude.

Part B

11. a) Describe the convolution property of 2D Fourier transform applicable for images.

Convolution theorem

If f(x) has a fourier transform F(u) and g(x) has a Fourier transform G(u) then

f(x)*g(x) has a fourier transform F(u).G(u).

Convolution in x domain can be obtained by taking the inverse Fourier transform

of the product F(u).G(u).

Convolution in frequency domain reduces the multiplication in the x domain

F(x).g(x) = F(u)* G(u)

These 2 results are referred to the convolution theorem.

b) Discuss in detail about the discrete Walsh transform of an image where N=4.

The Walsh transform is defined by

Where --------------1-D forward Walsh Kernel

The 1-D inverse Walsh transform is expressed as

Where --------------1-D Inverse Walsh Kernel

For N=4

x u	0	1	2	3
0	+	+	+	+
1	+	+	+	+
2	+	+	-	-
3	+	+	-	-

12. a) Explain about histogram equalization.

Histogram equalization

12.b.Discuss in detail about sharpening filters.

Sharpening filters in the spatial domain

· Basics

· Sharpening filters

Sharpening filters in the frequency domain.

· Smoothing filters

· Sharpening filters

13. a) Explain in detail image degradation model /restoration process in detail.

· Image degradation model /restoration process diagram

· Degradation model for Continuous function

· Degradation

b) Explain in detail about least mean square filtering with one application

Least mean square filtering

Properties of SVD

· The SVD transform varies drastically from image to image.

· The SVD transform gives best energy packing efficiency for any given

image.

· The SVD transform is useful in the design of filters finding least

Square, minimum solution of linear equation and finding rank of large

matrices.

14. a) Discuss in detail about lossless predictive coding.

Explanation with block diagram

· Reducing interpixel redundancies of closely spaced pixels.

· When predictive coding is used, the image has no need to be decomposed into bit planes or binary images

· New information=Actual value of pixel – Predicted value of that pixel

· The lossless predictive coding model includes both an encoder and a decoder

· The basic components of a predictive encoder are predictor, nearest integer block and symbol encoder

· The components of the predictive decoder are symbol decoder and predictor

14. b) Discuss in detail about various image compression standards.

· Binary image compression standards

· JPEG Standard(Continuous tone still Image compression standards)

· MPEG Standard(Video compression standards)

15. a) Explain in detail about Fourier descriptors and its usage

Boundary descriptors

. Simple descriptors.

. Fourier descriptors

b) i) Region growing by pixel growing.

Region growing is the process of grouping pixels or sub regions into larger regions based on a predefined similarity criteria

· Selection of seed points

· Selection of similarity criteria

· Formulation of a stopping rule

· Region growing algorithm

ii) Region split and merging techniques.

Region split and merging is a segmentation process in which an image is initially subdivided into a set of arbitrary, disjoint regions and then the regions are merged and/or split to satisfy the basic conditions

Quadtree;

A quadtree is a tree in which the nodes have exactly four descendants. The splitting technique can be represented using this quadtree

DIP:Electronics & Communication Engineering 7th semester notes

2010-11-10T23:24:00.000-08:00

DIP

EC1009-Digital Image processing

Part A

1. What is Image Sampling and Quantization?

Sampling means digitizing the co-ordinate value (x, y).

Quantization means digitizing the amplitude value.

2. List out the properties of FFT

The FFT properties are

1. Separability

2. Translation

3. Periodicity and conjugate symmetry

4. Rotation

5. Distributivity and scaling

6. Average value

7. Laplacian

8. Convolution and correlation

9. Sampling

3. Compare the spatial and frequency domain Methods.

In spatial domain approach, the pixels of an image are manipulated directly.

Frequency domain approach is mainly based on modifying the Fourier

transform of an image.

4. What are the effects of applying Butterworth filter to a noisy image?

The transfer function of a Butterworth low pass filter of order n and with cut of

frequency at a distance D0 from the origin is,

Where D(u,v) = [(u . M/2) + (v-N/2) ]

It reduces the spurious effect on the noisy image.

5. Draw the model of Image degradation System.

Noise n(x,y)

Image f(x,y) Degraded image g(x,y)

6. Define pseudo Inverse with an example.

It is the stabilized version of the inverse filter.For a linear shift invariant system

with frequency response H(u,v) the pseudo inverse filter is defined as

= 0 for H=0

7. What is inter pixel redundancy?

The value of any given pixel can be predicted from the values of its neighbors.

The information carried by is small. Therefore the visual contribution of a single pixel to

an image is redundant. Otherwise called as spatial redundant geometric redundant or

inter pixel redundant. Eg: Run length coding

8. How sub image size selection affect transform coding?

The sub image size selection is one of the most important factor that affects the

transform coding error and computational complexity. The level of compression and

computation increases as the sub image size increase.

9. How edge detection is used for detecting discontinuities in a image?

An edge is a boundary between two regions with relatively distinct gray levels

properties. The magnitude of the first derivative is used to detect the presence of a edge

in the image and the sign of the second derivative is used to determine whether the edge

pixel lies on the darker side or lighter side of an edge.

10 Name the approaches used to describe texture.

Texture is one of the regional descriptors. It provides measures of properties such

as smoothness, coarseness and regularity. There are 3 approaches used to describe texture

of a region. They are

· Statistical

· Structural

· Spectral

PART B

11. a) Explain the elements of digital Image processing system with a neat diagram.

1. Image acquisition

2. Preprocessing

3. Segmentation

4. Representation and description

5. Recongniton and Interpretation

6. Knowledge base

(or)

b) Write a detailed note on:

(i) Walsh Transform (8)

The Walsh transform is defined by

Where --------------1-D forward Walsh Kernel

The 1-D inverse Walsh transform is expressed as

Where --------------1-D Inverse Walsh Kernel

Discrete cosine Transform (8)

12. a) Discuss in detail Histogram Processing of a digital Image.

(or)

b) Write a detailed note on image enhancement in the frequency domain.

Low pass Filtering

High pass Filtering

13. a) What is image restoration? Explain the degradation model for continuous function

in detail.

(or)

b) Discuss about constrained least square restoration of a digital image.

14. a) Explain the image Compression models in detail.

Lossless Compression and Lossy compression.

Explain different types of compression models for three types of redundancies

(or)

b) Differentiate between lossless and lossy compression and explain transform

coding system with a diagram.

Lossless predictive coding	Lossy predictive coding
1. No loss of image information 2. Quantizer is not available 3. Less Compression is achieved	1. Lossy compression method 2. Quantizer is used 3. High compression is achieved with loss of image information

Transform coding

Block diagram of transform coding

Write about coding using 2-D DFT, DCT and Walsh transform

15. a) Explain the concept of Thresholding in image segmentation and discuss their

merits and limitation.

Bilevel Thresholding, Multilevel Thresholding

Global Thresholding

Local Thresholding

Dynamic and adaptive thresholding

(or)

b) Explain the boundary descriptors in detail with a neat diagram.

(i) Simple descriptors

i. Length

ii. Diameter

iii. Major axis, Minor axis

iv. Eccentricity

v. Basic Rectangle

vi. Curvature

(ii) Fourier Descriptors

(iii) Statistical moments

TQM:Electronics & Communication Engineering 7th semester notes

2010-11-10T23:22:00.000-08:00

TQM

Set 1

Subject: Total Quality management Code: MG1401

Branch: ECE, MECH.CSE

Semester: VII

Duration: 3 Hours Max.Marks:100

Note: Answer all the Questions

Part: A (Each question carries 2 marks)

What are the dimensions of quality?

Performance

Features

Conformance

Reliability

Durability

Service

Response

Aesthetics and

Safety

Define the term appraisal Cost.

Appraisal cost is the cost of verifying, checking or evaluating a product or service at various stages during the delivery process. It is a inspection cost.

Differentiate between Recognition & Reward.

Recognition is a form of employee motivation in which the organization publicly acknowledges the positive contributions an individual or team has made to the success of the organization.

Reward is something tangible such as a cash award, plaque, certificate, special dinner, theatre tickets, etc. to promote desirable behavior.

Define Empowerment.

Empowerment requires a sincere belief and trust in people. It involves employees directly in decision-making processes, giving them the security and confidence to make decisions, and providing them with the necessary tools and training.

What are the new management tools of quality?

The new seven management tools are: (1) Affinity diagram, (2) Relationship diagram,

(3) Tree diagram, (4) Matrix diagram, (5) Prioritization matrix, (6) Process decision program chart (PDPC), and (7) Activity network diagram.

Define process capability ratio.

Process capability is measured by a process capability index (C_P) which is defined as the ratio of the specification width to the natural tolerance of the process.

C_P = (USL – LSL) / 6σ [where USL – LSL = upper specification – lower specification, or tolerance and σ = standard deviation].

What is QFD?

Quality Function Deployment (QFD) is a technique to bring the voice of the customer into the process of designing and developing a product or service

Name the pillars of TPM.

The eight pillars of TPM, identified by the Japanese, help in improving the OEE. The eight pillars are: [1] 5S, [2] Jishu Hozen (Autonomous Maintenance), [3] Kobetsu Kaizen (KK), [4] Planned Maintenance (PM), [5] Quality Maintenance (QM), [6] Training, [7] Office TPM, and [8] Safety, Health and Environment

Differentiate QMS & EMS.

ISO 9000 definition of Quality Management System: “The organizational structures, responsibilities, processes, procedures, and resources used for implementing quality”.

QMS involves: How – methods, processes; Who – responsibilities, authorities; When – records, evidence; Where – identification, traceability

The ISO 14000 standards are a set of norms for Environmental Management System (EMS) either at organization level or product level.

What are the stages of audit?

1. Audit planning – schedules, personnel, notifications, checklist.

2. Performance – opening meetings, audit process, noting of non-conformities.

3. Reporting – Observations, suggestions for corrective action

4. Follow-up – implementation of corrective action.

Part:B (Each question carries 16 marks)

11 (a). (i) Explain the basic principles of TQM

PRINCIPLES OF TQM:

1. Management commitment, 2. Focus on customer (both external and internal), 3. Employee involvement, empowerment, 4. Continuous improvement, 5. Treating suppliers as partners, 6. Establish performance measures for processes, 7. Designing products for quality, 8. Quality at source, 9. Defect prevention, 10. Root cause corrective action, 11. Benchmarking, 12. Training, 13. Positive motivation, 14. Team work, 15. Management by fact, and 16. Quick response.

(ii) Discuss the barriers to TQM implementation

the following are some of the major obstacles encountered in implementation:

1. Lack of management commitment: Management does not allocate sufficient time and resources for TQM implementation. The purpose is not clearly, consistently communicated to all personnel. Management’s compensation is not linked to quality goals such as failure costs, customer complaints, and cycle time reduction.

2. Inability to change organizational culture: Even individuals resist change; changing an organization’s culture is much more difficult and may require as much as 5 years or more. Exhortations, speeches, slogans are effective only in the short run.

3. Improper planning: Absence of two-way communication of ideas during the development of the plan and its implementation.

4. Lack of continuous training and education.

5. Incompatible organizational structure and differences between individuals/departments.

6. Ineffective measurement techniques for key characteristics of the organization. Lack of access to data and results.

7. Paying inadequate attention to internal and external customers. Inability to understand the changing needs and expectations of customers. Absence of effective feedback mechanisms.

8. Inadequate use of empowerment and teamwork.

9. Lack of employee involvement.

10. Non-cooperation of first-line managers and middle management.

11. Lack of clarity in vision.

12. Emphasis on short-term results.

13. Setting of unmanageable, unrealistic goals.

14. Bureaucratic system.

15. TQM is considered as a quick-fix solution to current problems.

16. Treating suppliers as adversaries to be manipulated, taken advantage of.

17. Adversarial relationship between workers/unions and management.

18. Motivating employees through fear of punishment.

19. Failure to continually improve. Tendency to sit back and rest on one’s laurels. Rigidly sticking to one ‘success formula’.

( discuss any 8 points )

(b) Explain Deming’s 14 philosophy

Deming’s 14 points for Management:

1. Create and publicize to all employees the aims and purposes of the organization.

2. Adopt the new philosophy (of customer satisfaction, continuous improvement, defect prevention, management-labour cooperation, etc.).

3. Stop dependence on inspection to achieve quality. (Managers must understand how variation affects their processes and take steps to reduce the causes of variation. Workers must take responsibility for their own work).

4. End the practice of awarding business on the basis of price tag alone. (Costs due to inferior materials/components increase costs in the later stages of production. Suppliers themselves are part of the whole system and hence should be treated as long-term partners).

5. Improve constantly and forever the system of production and service .(Aim for small, incremental, continuous improvements – not merely in the area of production but also covering transportation, maintenance, sales, service, administration, etc. – all areas of the organization).

6. Institute training. (Employees need the proper tools and knowledge to do a good job, and it is management’s responsibility to provide these. Training not only improves quality and productivity, but also enhances workers’ morale).

7. Adopt modern methods of supervision and leadership. (Managers, Supervisors should act as coaches, facilitators and not as policemen).

8. Drive out fear. (Fear in work manifests as fear of reprisal, fear of failure, fear of change, fear of the unknown. Fear encourages short-term, selfish thinking, not long-term improvement for the benefit of all).

9. Break down barriers between departments and individuals. (Promote teamwork).

10. Eliminate the use of slogans and exhortations. (Workers cannot improve solely through motivational methods when the system in which they work constrains their performance. On the contrary, they will become frustrated, and their performance will decrease further).

11. Eliminate work standards, numerical quotas, and MBO. (Numerical quotas reflect short-term perspectives and do not encourage long-term improvement. Workers may shortcut quality to reach the goal. The typical MBO system focuses on results, not processes, and encourages short-term behavior).

12. Remove barriers to pride in workmanship. (Treating workers as commodities; giving them monotonous jobs, inferior tools; performance appraisals, management assuming it is smarter than workers and not using the workers’ knowledge and experience to the fullest extent).

13. Encourage education and self-improvement for everyone.

14. Take action to achieve the transformation. (The TQ philosophy is a major cultural change,and many firms find it difficult. Top management must take the initiative and include everyone in it).

12 (a) Define Teams. What are the various types of teams? Explain their roles & functions.

TEAMS

* A team is defined as a group of people working together to achieve common objectives or goals. Teamwork is the cumulative actions of the team in which each member of the team subordinates his individual interests to fulfill the objectives or goals of the group. The objective or goal may be to solve a problem, improve a process, design a product, plan a conference, and so on.

* Teams work because many heads are more knowledgeable than one. Each member of the team has special abilities that can be used to solve problems. Many processes are so complex that one person cannot be knowledgeable concerning the entire process.

* Traditionally, human resources management has focused on individuals. Practices such as MBO, individual performance evaluation, and individual promotion result in rivalries, favoritism and self-centeredness which work against accomplishing the true mission of an organization. Team-work breaks down barriers between individuals, departments, and line and staff functions.

* In a TQ environment, teamwork takes on a new meaning. Teams may perform a variety of problem solving activities, such as determining customer needs, brainstorming to discover opportunities for improvement, selecting projects, recommending corrective actions, and tracking effectiveness of solutions.

* Effective teams are goal-oriented, independent, open, supportive and empowered. Problem solving drives the team concept. The three basic functions of a team are to identify, analyze and solve quality and productivity problems. These three basic functions can be expanded into the following nine steps:

Identify: 1. Develop list of problems, 2. Select problem to tackle.

Analyze: 3. Collect data, 4. Focus attention, 5. Find causes.

Solve: 6. Develop solutions, 7. Pick best solution, 8. Develop follow-up plan, and 9. Implement.

* The development of Quality Circles by the Japanese in 1961 is considered to be the beginning of the use of teams to improve quality. Quality Circles are groups of people from one work unit who voluntarily meet together on a regular basis to identify, analyze, and solve quality and other problems within their area. Various other types of teams have subsequently come up to tackle diverse issues in a TQ environment. Some of these are:

Process improvement teams: The members represent each operation of the process. When the targeted process includes many work units or the entire organization, a cross-functional team may be more appropriate with work unit teams operating as sub-teams. The life cycle of this type of team is usually temporary – it is disbanded when the objective has been achieved.

Cross-functional teams: The members represent a number of different functional areas such as engineering, marketing, accounting, production, quality, and human resources. It may also include the customer and/or the supplier. A design review team is a good example of a cross-functional team. This type of team breaks down functional area boundaries.

Problem-solving teams: Members gather to solve a specific problem and then disband.

Project teams: Teams with a specific mission to develop something new or to accomplish a complex task.

Self-directed/self-managed work teams: They are the epitome of the empowered organization – they not only do the work but also manage it. There is wide discretion to organize their work subject to organizational work flow requirements.

(b) Write short notes on:

a) Juran Trilogy

b) PDSA cycle

c) Kaizen

d) 5’S concept

JURAN TRILOGY

* Joseph Juran, like Edwards Deming, was a US citizen who taught quality principles to the Japanese in the 1950s and was a principal force in their quality reorganization. Juran’s prescriptions focus on three major quality processes, called the Quality Trilogy: (1) quality planning – the process of preparing to meet quality goals, (2) quality control – the process of meeting quality goals during operations, and (3) quality improvement – the process of breaking through to unprecedented levels of performance.

(1) Quality planning: Quality planning begins with identifying customers, both external and internal, determining their needs and developing product features that respond to those needs. Juran wanted employees to know who uses their products, whether in the next department or in another organization. Quality goals based on meeting the needs of customers and suppliers alike at a minimum combined cost are then established. Next, the process that can produce the product to satisfy the customers’ needs and meet quality goals must be designed.

(2) Quality control: Quality control involves determining what to control, establishing units of measurement to evaluate data objectively, establishing standards of performance, measuring actual performance, interpreting the difference between the actual performance and the standard, and taking corrective action on the difference.

(3) Quality improvement: The third part of the trilogy aims to attain levels of performance that are significantly higher than current levels. Process improvements begin with the setting up of an effective infrastructure such as the quality council. The duties of the council are to identify improvement projects, establish project teams, and provide the teams with required resources. The teams work to identify the causes, create solutions, and establish controls to hold on to the gains. The quality council is the catalyst that ensures that improvement is continuous and never ending. Process improvement can be incremental or breakthrough.

PDSA CYCLE

* Also known as the Deming Cycle and Deming Wheel, it is a simple methodology for continuous improvement that was strongly promoted by Edwards Deming. It was originally called the Shewhart Cycle after its original founder, Walter Shewhart, but was renamed the Deming Cycle by the Japanese in 1950. The Deming Cycle is composed of four stages: plan, do, study, and act (PDSA). (The third stage – study – was formerly called check, and the Deming Cycle was originally known as the PDCA cycle. Deming made the change in 1990. He felt that “study” is more appropriate, while with “check”, one might miss something).

* The plan stage consists of studying the current situation and describing the process: its inputs, outputs, customers, and suppliers; its start, end, and what it does; the key tasks performed and sequence of steps, people involved, equipment and materials used, work methods; understanding customer expectations; gathering data; identifying problems; testing theories of underlying causes; and developing solutions and action plans.

* In the do stage, the plan is implemented on a trial basis, for example, in a laboratory, pilot production process, or with a small group of customers, to evaluate a proposed solution and provide objective data. Data from the experiment are collected and documented.

* The study stage determines whether the trial plan is working correctly by evaluating the results, recording the learning, and determining whether any further issues or opportunities need to be addressed. Often, the first solution must be modified or scrapped. New solutions are proposed and evaluated by returning to the do stage.

* In the act stage, the best change or solution is selected and an implementation plan is developed. The improvements become standardized and the final plan is implemented as a “current best practice” and communicated throughout the organization. This process then leads back to the plan stage for identification of other improvement opportunities.

The fundamental premise of the Deming Cycle is that improvement comes from the application of knowledge. This knowledge may be knowledge of engineering, management, or how a process operates that can make a job easier, more accurate, faster, less costly, safer, or better meet customer needs. The Deming Cycle is never-ending, i.e. it is focused on continuous improvement. The improved process is only a springboard for further improvements.

5S PRINCIPLES

* Japanese factories are well known for their cleanliness and orderliness.

* A dirty factory cannot produce quality products. Similarly a person of disorderly habits cannot be efficient and effective at work.

* The 5S Principles is a technique for effective workplace management. It is a tool for high quality housekeeping, thereby improving workplace effectiveness.

* The 5S’s stand for five Japanese words: Seiri, Seiton, Seiso, Seiketsu, and Shitsuke. The 5S is not only useful to improve the physical environment, but also the thinking processes.

1. Seiri (Sort): Separate out all unnecessary things and remove them, retaining only necessary things. Accumulation, mixing of unnecessary things and wastes with needed items leads to clutter, confusion and mess, thereby reducing the efficiency of working. Seiri also involves keeping the number of things as low as possible and at a convenient location. If the workplace is clean, there is greater motivation to carry out the job; but if the place is full of unwanted things, it will be difficult to work effectively.

2. Seiton (Arrange): Put required things in proper order so that they can be easily accessed for use and quickly put away in their proper locations after use. It prevents people from wasting their time searching for things. “A place for everything and everything in its place”.

3. Seiso (Clean up): Keep machinery and work environment clean. Employees should be responsible for cleaning their own workplaces. Workers should clean up the workplace first thing before they commence work and at the end of the day before they leave. They should also see that their workplace remains clean and tidy throughout the day. Any dirt, spillage, etc. should be attended to immediately.

If cleanliness is not maintained, it can be harmful to the personnel [health hazards], machinery [can fail due to dust, dirt, etc.], and materials [due to contamination], thereby causing quality and productivity problems.

4. Seiketsu (Systematize, Standardize): Develop routine practices for orderly, systematic working. If the 5S processes are standardized, it becomes easier to continuously maintain the organization’s neatness and cleanliness. An effective means of achieving Seiketsu is Visual management – like signboards, marked parking lots, marking of aisles, identification labels, etc. Another important consideration is transparency – tools, files, etc. should be visible so that it is easy to locate them. This will reduce the time for searching.

5. Shitsuke (Discipline): Impart systematic training and coaching to ensure discipline in 5S implementation. Discipline comes through repetition and practice. Self-discipline goes beyond discipline. It is essential for the successful implementation of the 5S principles.

* In a factory, 5S increases productivity, eliminates waste, reduces inventory, creates a pleasant workplace, improves safety, and increases the overall efficiency and effectiveness of people and machines.

* The logic behind the 5S principles is that organization, neatness, cleanliness, standardization, and discipline at the workplace are basic requirements for producing high quality products and services, with high productivity and little or no wastage; hence the importance of combining the 5S principles in TQM.

KAIZEN

* Kaizen, which is a Japanese word that means gradual and orderly continuous improvement, is a philosophy that covers all business activities and everyone in an organization. In the kaizen philosophy, improvement in all areas of business – cost, meeting delivery schedules, employee safety and skill development, supplier relations, new product development, and productivity – serve to improve the quality of the firm. Thus, any activity directed toward improvement falls under the kaizen umbrella.

* For example, statistical process control, robotics and advanced technology, employee suggestion schemes, total productive maintenance, just-in-time production systems all lead to improvement and fall under the kaizen umbrella.

* Kaizen begins with the notion that an organization can assure its long-term survival and success only when every member actively pursues opportunities to identify and implement improvements everyday. Kaizen sets no conditions for the magnitude of improvement. In fact, it often favors small, incremental improvements.

* By instilling kaizen into people and training them in basic quality improvement tools, workers can build this philosophy into their work and continually seek improvement in their jobs. This process-oriented approach to improvement encourages constant communication among workers and managers.

* The kaizen philosophy has been widely used by many firms in the US and around the world. For example, at ENBI Corporation, a New York manufacturer of components for the printer, copier, and fax machine markets, kaizen projects resulted in a 48% increase in productivity, a 30% reduction in cycle time, and a 73% reduction in inventory. At Mercedes-Benz’s truck factory in Brazil, kaizen resulted in reductions of 30% in manufacturing space, 45% in inventory, 70% in lead time, and 70% in setup time over a three-year period.

13 (a) The following data are obtained from an automatic filling process of certain chemical delivered into each container. The specification of the mass delivered is 50 + 4 grams. Samples of 4 are taken from 10 successive samples as shown in table.

Use A₂ = 0.73, D₄ = 2.28, D₃ = 0 and d₂ = 2.059.

Samples

1 2 3 4 5 6 7 8 9 10

51 52 51 48 53 51 52 54 53 50

observations50 53 52 49 49 49 53 52 53 52

52 52 52 52 49 49 47 51 52 52

49 54 51 49 54 50 52 53 54 53

I) Determine the control limits for X bar and R charts

II) Is the machine capable of meeting the specification requirements?

Solution:

Control limits for X bar and R charts

X double bar = 51.35

UCL = 53.613

LCL = 49.087

R chart = 3.1

UCL = 7.068

LCL = 0

Process capability ratio =0.8856

PCR < 1

The machine is not capable of meeting the specification requirements.

13 (b) Explain the DMAIC & DMADV models in six sigma

Six sigma implementation models: There are two basic models for six sigma implementation:

1) DMAIC model (for improving existing processes) and

2) DMADV model (for design of new products to achieve six sigma quality).

(1) DMAIC model: It is a 5-step process improvement model. The steps are: Define, Measure, Analyze, Improve, and Control.

i) Define: Define the six sigma project to be taken up. Select the team. Identify the customers (internal and external). Identify the critical to quality (CTQ) issues, i.e. key performance measures. Document the existing process. Describe the current level of performance.. Benchmark best performance standards. Calculate the cost/revenue implications of the project. Decide what needs to be done, by whom, and when.

ii) Measure: Identify appropriate measures for assessing performance. Define target performance based on customer requirements (through benchmarking, if necessary). Measure current performance and identify the gaps.

iii) Analyze: Discover the causes for the gaps/shortfalls/defects. Identify key variables which cause the defects (through a cause-and-effect diagram, if necessary). Group the influencing factors into the following three categories:

Constants (C): these factors cannot be changed.

Noise factors (N): while efforts should be made to reduce noise, these can’t be eliminated

Experimental factors (X): these factors can be modified to improve the results.

In this way, identify the parameters to be experimented with in order to improve the process.

iv) Improve: Fix maximum permissible ranges of the key variables. Devise a system to measure deviations of the variables. Modify the process to ensure that variations occur within the permissible range. Implement the solution on a pilot basis. Monitor and measure performance. Standardize the improved method if performance is successful.

v) Control: Put in place systems and procedures to ensure that key variables remain within the maximum permissible ranges continuously. These might include establishing new standards and procedures, training the workforce, and instituting controls to make sure that improvements do not die over time.

(2) DMADV model: DMADV stands for Define, Measure, Analyze, Design, and Verify. It is employed for design of new products to achieve 6-sigma quality.

i) Define: This phase is similar to the DMAIC model. The only difference is that ‘document the existing process’ and ‘describe the current level of performance’ do not arise.

ii) Measure: Identify customer needs and convert them into technical requirements through Quality Function Deployment (QFD) technique. Define measures for each of the technical requirements and define performance standards for the process.

iii) Analyze: Generate various design options for the concept. Evaluate them and select the right option.

iv) Design: Detailed design stage involving finer details and identifying all the required steps in the process. This is followed by system integration. This step may involve the fabrication of prototypes or establishing a pilot plant.

v) Verify: Verify and validate the functionality of the product or process. Document the findings and transfer to regular production.

14 (a) Define Benchmarking. Discuss the types and steps in benchmarking process

Benchmarking is a systematic method by which organizations can measure themselves against the best industry practices. It helps them learn how the “best in class” do things, understand how these best practices differ from their own, and implement change to close the gap. The essence of benchmarking is borrowing ideas and adapting them to gain competitive advantage. It is a tool for continuous improvement

Types:

Competitive Benchmarking

Functional Benchmarking

Internal Benchmarking

Product Benchmarking

Process Benchmarking

Best Practices Benchmarking

Strategic Benchmarking

Parameter Benchmarking

The benchmarking process: It consists of the following six steps: [1] Decide what to benchmark. [2] Understand current performance. [3] Plan. [4] Study others. [5] Learn from the data. [6] Use the findings. Brief explanations of these steps is furnished below:

[1] Decide what to benchmark:

* Benchmarking can be applied to virtually any business or production process. In general, it is best to begin by thinking about the mission and the critical success factors of the organization. Some other questions that can be raised to decide high impact areas to benchmark are: Which processes are causing the most trouble? Which processes are not performing up to expectations? Which processes contribute most to customer satisfaction? What are the competitive pressures impacting the organization the most? What processes or functions have the most potential for differentiating our organization from the competition?

[2] Understand current performance:

* It is first necessary to thoroughly understand and document the current process. Those working in the process know the most about it. Hence the benchmarking team should be comprised of those who own or work in the process. Examples of key metrics for measurement are: unit costs, hourly rates, quality measures, etc. Techniques such as flow diagrams and cause-and-effect diagrams aid understanding.

[3] Plan:

* A benchmarking team is chosen. The team should decide what type of benchmarking to perform, what type of data is to be collected, the method of data collection, the candidate organizations to be benchmarked, and the time table for the various tasks required to be performed.

* There are three main types of benchmarking: internal, competitive, and process.

+ Internal: In most large firms, similar activities are performed in different operating divisions. Data are easy to obtain for internal comparisons.

+ Competitive: Product competitors are an obvious choice to benchmark. However, some organizations would never knowingly share proprietary information. But there are several ways to obtain such data – information in public domain, and through third parties. Buying a competitor’s product to take apart and test is another common practice.

+ Process: Many processes are common across industry boundaries, and innovations from other types of organizations can be applied across industries. For example, every industry has payroll and accounts functions. All kinds of organizations design new products and have logistics functions. Motorola looked to Domino’s Pizza and Federal Express for the best ways to speed up delivery systems.

Thus best practices can be found internally, in a competitor, in the industry, in another indigenous organization, or in a global organization.

[4] Study others:

* Benchmarking studies look for two types of information: a description of how best-in-class processes are practiced and the measurable results of these practices. Primary data, secondary data and site visits are useful sources of information for carrying out the studies.

[5] Learn from the data:

* Learning from the data collected in a benchmarking study involves answering a series of questions: Is there a gap between the organization’s performance and that of the best-in-class organizations? What is the gap? How much is it? Why is there a gap? What does the best-in-class do differently that is better? If the best-in-class practices were adopted, what would be the resulting improvement?

* Summary measures and ratios, such as activity costs, return on assets, defect rates, customer satisfaction levels, etc. can be calculated and compared.

[6] Use the findings:

*. To effect change, the findings must be communicated to all concerned. The findings must translate to objectives, goals and action plans.

* Benchmarking is a continuous improvement tool. In order to avoid complacency, it must be used continuously to pursue emerging new ideas.

(b) Explain the House of Quality matrix and its components with a suitable example

The House of Quality (HOQ), so called because of its shape, is the basic tool used in QFD. It is a set of matrixes used to relate the VOC to a product’s technical requirements, component requirements, manufacturing plans and manufacturing operations. The first matrix, the customer requirement planning matrix, provides the basis for the QFD concept. It basically shows what the customer wants and how the organization is going to fulfill those wants.

Basic steps in building a House of Quality:

1. Identify customer requirements, 2. Identify technical requirements, 3. Determine the inter-relationships among the technical requirements, 4. Relate the customer requirements to the technical requirements, 5. Evaluate competitors’ offerings and determine key selling points,

6 Evaluate technical requirements and develop targets, and 7. Select technical features to deploy in the remainder of the production/delivery process.

Brief explanations of the above steps:

1. Identify customer requirements: The Voice of the Customer (VOC) is the primary input to the QFD process. Information is gathered from customers about their needs, wants and expectations. The customer’s own words are vitally important in preventing misinterpretation by designers and engineers. Some important sources of information for VOC are: direct customer feedback, focus groups, customer complaints, market survey of customers, information from sales team and service team, comparative analysis of competitors’ products through benchmarking, etc. The customer needs are ranked in order of importance.

2. Identify technical requirements: These are design characteristics that express the customer requirements in the language of the designer or engineer. They are the “hows” by which the company will respond to the “whats” – the customer requirements.

3. Determine inter-relationships among the technical requirements: The roof of the HOQ is a triangular matrix that shows the inter-relationships between any pair of technical requirements. Various symbols denote these relationships. [ O – strong relationship, O – medium relationship,

∆ - weak relationship, blank – no relationship, and X – negative relationship]. This diagram allows the user to identify which technical features support one another and which are in conflict. Conflicting technical requirements may indicate conflicting customer requirements and hence, represent points at which tradeoffs must be made. Early resolution of tradeoffs is essential to shorten product development time.

4. Relate the customer requirements to the technical requirements: Here also the above symbols are used to show the degree of relationship. The purpose of this matrix is to show whether the final technical requirements adequately address the customer requirements. It will be difficult to meet customer requirements without at least one strong relationship in every row. The lack of a strong relationship shows that customer needs are not addressed or the design will not be able to meet them. An empty row indicates that a customer requirement is not being met. An empty column indicates that a particular design feature is redundant.

5. Evaluate competitors’ offerings and determine key selling points: Assign importance ratings (from 1 to 5) for each customer requirement and evaluate competitors’ products/services for each of them. If an important customer requirement gets low rating on all competitors’ products, such requirements indicate scope to gain competitive advantage and can become key selling points.

6. Evaluate technical requirements and develop targets: On the basis of customer importance ratings and existing product strengths/weaknesses, targets are set for each technical requirement.

7. Select technical features to deploy: Select technical requirements to deploy in the remainder of the production process. Technical requirements that have a strong relationship to customer needs, have poor competitive performance, or are strong selling points are identified and deployed.

15(a) Briefly explain the concepts, requirements and benefits of ISO 14000.

ISO 14000 STANDARDS

* The ISO 14000 standards are a set of norms for Environmental Management System (EMS) either at organization level or product level. It was developed by the International Organization for Standards (ISO) in 1992 after the success of ISO 9000 (set up in 1987).

* Rationale for ISO 14000:

(i) World-wide focus on environment based on internationally accepted criteria.

(ii) It prevents conflicts between regional interpretations of good environmental practice.

(iii) Certification is required to compete in global marketplace.

* ISO 9000 standards exist in two areas: [1] Organizational evaluation standards, and [2] Product evaluation standards.

* Requirements of ISO 14000 (Major elements of EMS standards):

[1] General requirements, [2] Environmental policy, [3] Environmental aspects, [4] Legal aspects, [5] Objectives & targets, [6] Environmental management program, [7] Structure & responsibility, [8] Training, awareness and competency, [9] Communication, [10] Documentation, [11] Document control, [12] Operational control, [13] Emergency preparedness & response, [14] Monitoring & measuring, [15] Non-conformance, corrective and preventive action, [16] Records, [17] EMS audit, and [18] Management review.

Benefits of EMS :

Improves international trade and remove trade barriers
Improves environmental performance of planet earth and
Build consensus that there is a need for environmental management

(b) Write short notes on

I) Policy, procedure, work instruction, records in ISO 9000.

II) Quality auditing

Types of documents found in ISO 9000 system:

1) Quality Policy Manual (What? Why?)

· First tier of documentation process

· Define what will be done and why

· Quality policy manual will be written – clear, precise, practical & easy to understand

· Short and simple definition of the organization’s quality intensions

2) Quality System Procedures (Who? When? Where?)

· Second tier

· Procedure describes the methods that will be used to implement the stated policies

· Who should perform specific tasks

· When the task should be done

· Where documentation will be made

· Applicable to all areas within the organization

· More detailed than policies

· Allows for easy understanding

3) Work Instructions (How?)

Spell out how a job will be done
Usually dept, machine, task or product oriented
Detailed drawimg or routing sheet or specific job
Pride of ownership in the document function

3) Records, formats, forms (Evidence)

· Way of documenting that policies, procedures and work instructions have been followed

QUALITY AUDITS:

* Definition of quality system audit: “a systematic, independent examination to determine whether quality activities and results comply with planned arrangements, whether these arrangements are implemented effectively, and whether these are suitable to achieve objectives”.

Types of audit: First party audit (internal), Second party audit (by customer), and Third party audit (by independent agency).

Another classification: System audit, Process audit, Product audit, Adequacy audit, and Compliance audit.

* Stages in conducting quality audit:

1. Audit planning – schedules, personnel, notifications, checklist.

2. Performance – opening meetings, audit process, noting of non-conformities.

3. Reporting – Observations, suggestions for corrective action

4. Follow-up – implementation of corrective action.

============================

VLSI:Wafer Processing

2010-11-10T23:17:00.000-08:00

Wafer Processing(VLSI)

•Basic raw material – wafer – disk of silicon

•Dia varies from 75mm to 230mm

•Thickness - less than 1mm (0.25mm – 1mm)

•Wafer are cut using diamond blades from ingots of single silicon crystal pulled from a melt of polycrystalline silicon

•Quartz crucible surrounded by graphite radiator temp ~~1425 C.

•Atmosphere above is Argon or Helium

•Impurities added determine the electrical characteristics

•Crystal orientation determined by seed

•Growth rates - 30 – 180 mm /hr

•One face is polished to a flat , scratch free mirror finish

Oxidation

•By heating the wafers in an oxidizing atmosphere such as oxygen or water vapour.

»Wet oxidation – atmosphere contains water vapour 900ºC to 1000ºC , rapid process.

»Dry oxidation: atmosphere contains pure oxygen. 1200ºC

•SiO2 layer grows equally in both directions

Epitaxy, Deposition, Ion – implantation & Diffusion

•● To generate silicon that contains varying

portions of donor or acceptor impurities.

•Epitaxy: Grow a single crystal film on the silicon

surface, by subjecting silicon wafer to elevated

temp and exposing to dopants.

•Deposition : Evaporate dopant material onto the

silicon surface followed by a thermal cycle (to drive

the impurity from the Si surface into the bulk)

•

•Ion implantation : Subject the Si substrate to

highly energized donor

or acceptor atoms. The injected impurities will

travel below the surface of

the Si, forming regions with varying doping

concentration.

•Diffusion : Occurs at temp. > 800ºc between Si

and dopants.

Impurities will diffuse from areas of high

concentration to area

of low concentration.

Construction of devices depends on ability to control the above processes.

Note: =>It's important once the doped areas have been put in place,

to keep the remaining process steps at as low a temperature

as possible.

● Impurities: Boron : acceptors

Arsenic, phosphorous : donors

● Amount is controlled by

1. energy and time of “Ion implantation”.

2. Time and temperature of “deposition” and “diffusion”.

● Where deposition depends on masks

- Common materials used as masks include:

1. photoresist

2. polysilicon (polycrystalline silicon)

3. silicon dioxide (SiO2)

4.silicon Nitride (Si3N4) (SiN)

Function of the mask : form a barrier against doping impurities

selective diffusion - steps

1. patterning "windows" in a mask material on the surface of the wafer

2. subjecting exposed areas to a dopant source.

3.remove any undesired mask materials.

● SiO2 is removed using an etching technique.

A. Use a acid resistant coating (photoresist)(PR), which can be polymerized by ultraviolet (UV) light.

B. The polymerized areas may be removed with an organic solvent.

C. Etching of exposed SiO2 then may proceed.

•A-B-C "Positive resist“

•"Negative resist" = unexposed PR is dissolved by the solvent.

•*Note diffraction around the edges of the mask patterns (= 0.8µm)

•

Alternative approach : high cost, precise -Electron beam lithography (EBL)

Line widths of 0.5µm with good definition are achievable

Main adv:

1.Patterns are derived directly from digital data.

2.No intermediate H/W images such as masks.

3.Different patterns may be accommodated in diff sections without any difficulty.

4.Changes can be implemented quickly.

Electronics & Communication Engineering 7th semester notes

2010-11-10T23:09:00.000-08:00

PART-A (10 x 2 = 20marks)

List any 4 advantages of SOI over n & p well processes.

· Denser packing of devices is possible.

· Lowered substrate capacitance – Faster ckts.

· No latch – up as substrate is insulator.

· Enhanced tolerance to radiation.

What is a LDD structure.

LDD stands for Lightly doped drain. It is a technology used to overcome hot electron effect. Initially the drain/source is lightly doped and over the gate a spacer oxide is grown over this a heavier implant is done, moving higher concentration of electrons away from gate.

Name 4 popular materials used as masks

Silicon di oxide

Photo resist

Poly - silicon

Silicon Nitride.

Name the two kinds of CMOS layout rules and give the minimum size for n- well layer in each of them.

Lamda rule - 10λ , Micron rule - 2µ.

Draw the ckt of a two input CMOS NAND gate.

What are the 2 kinds of delays in verilog statements?

1) Inter statement

A= b + c;

#5 c = A + x;

2) Intra statement

A = #5 b+c;

Construct a 2 x 1 MUX using tristate primitives.

A 2 X 1 MUX can be constructed using one bufif0 and one bufif1 as shown below.

Give the syntax of two conditional statements.

1) if (expression) statement;

2) if (expression) statement1;

else (expression) statement2;

3) if (expression) statement1;

else if(expression) statement2;

else if(expression) statement3;

---

----

else default statement.

Explain the compiler directive - timescale.

‘ timescale 1ns/100ps – is the syntax for this compiler directive . Here 1ns is the defined time unit and 100ps is the precision.

Define an identifier.

An identifier is a single group of characters which is used to reference the modules, objects and variables . It can be lower case and upper case alphabets, numbers from 0 to 9, $ (dollar) and _ (under score). It has to begin with a alphabet or under score. Verilog is case sensitive.

Set - II

PART-A (10 x 2 = 20marks)

Explain the different oxidation methods used in CMOS fabrication

a) wet oxidation: Oxidizing the silicon wafer in the presence of water vapour between 900 C – 1000 C .This is a rapid process.

b) Dry oxidation : Oxidizing the silicon wafer in the presence of oxygen around 1200 C . Acceptable growth rate.

List the advantages of twin tub over n / p- well processes.

· Used for protection against latch-up

· Provides separate optimization of p-type & n-type transistors

What are the different tools available in a typical CAD tool set?.

Design rule checker and Mask circuit – extraction program.

Draw the ckt of a CMOS 2 input NOR gate.

Define MSI, LSI and VLSI.

MSl:Medium-scaleIntegration, 10<1000
LSl:Large-scaleIntegration, Gates>1000
VLSI: Very Large-scale Integration, Gates>100000

What is the difference between = = = and = = in Verilog ?

= = = is used for case equality and = = is used for identity in Verilog HDL.

What is gate delay.

Verilog provides techniques for introducing delays at gate level.

The delay through agate is modeled using a single delay time – propagation delay

If rise time and fall time are known they are specified as

nand # (t_rise,t_fall) G1( out,a,b );

Turn off delay can be specified as nand # (t_rise, t_fall, t_off) G1( out,a,b );

Give the symbol, Truth table and syntax of bufif1.

SYNTAX: bufif1 instance_name( out,in,ctrl);

		ctrl
		0	1	X	z
in	0	z	0	L	L
	1	z	1	H	H
	x	z	x	x	x
	z	z	x	x	x

Give the structural coding of a half adder.

module half (a,b,s,c);

input a;

input b;

output c;

output s;

xor (s,a,b);

and (c,a,b);

endmodule

Explain the significance of zero based delay.

Statements with # 0 delay are always executed last in the execution time step. This also avoids races.

2010-08-24T19:45:00.000-07:00

Electronics and Communication Engineering Department subject codes as per 2007-2011 (Mark system).
1st and 2nd semester:
CY1X01 Engineering Chemistry
EC1X01 Electron Devices
EC1X02 Circuit Analysis
GE1X01 Engineering Graphics
GE1X02 Computer Programming
HS1X01 Technical English
MA1X01 Engineering Mathematics-1
PH1X01 Engineering Physics
GE1X03 Engineering Practices Laboratory
PC1X01 Physics and Chemistry Laboratory

2010-05-14T22:55:00.001-07:00

Bachelor of Engineering(B.E)/
B.TECH DEGREE EXAMINATION,APRIL/MAY 2010

Sixth semester

ELECTRONICS AND COMMUNICATION ENGINEERING

CS1251-COMPUTER ARCHITECTURE

(Common to Fourth Semester Computer Science and Engineering/
Information Technology)

(Regulation 2004)

(Common to Bachelor of Engineering (Part-Time)Fifth Semester
Regulation 2005)

Time:3hrs Max:100marks

Answer ALL the questions.

PART-A (10x2=20 marks)

1. What is meant by Central Processing Unit?

2. Define Control Bus.

3. How do you convert 2’s complement to decimal?

4. Draw the logical circuit for array multiplication.

5. When does imprecise exception arise?

6. Compare horizontal and vertical format.

7. What is TLB?

8. How is average access time of two level memory systems computed?

9. Explain why cannot I/O devices be connected directly to the system bus.

10. State the widely used bus standards.

PART-B (5x16=80marks)

11. (a)What are the basic instruction types? Explain with suitable examples.

(b)What is the need for different addressing modes? Explain the various addressing modes with

the examples.

12. (a)(i) Perform 25 x (- 16) using booth’s multiplication algorithm.

(ii) What are the problems in floating point arithmetic ?

(b) Describe the algorithm for integer division with suitable example.

13. (a)Explain the various types of pipeline hazards and their resolution mechanisms in detail.

(b)Explain the various branching techniques used in micro programmed control unit.

Illustrate the micro operations with the help of a flowchart for the instruction :Add src,

Rdst instruction.

14. (a) Explain in detail the internal organization of a memory chip.

(b) Explain the various types of optical memory in detail.

15. (a) Explain various bus arbitration mechanisms in DMA transfer.

(b) Discuss the data transfer mechanism of the PCI bus.

@@@@@@@

2010-05-11T05:40:00.001-07:00

B.E. / B. Tech. DEGREE EXAMINATION, APRIL/MAY 2010.

Sixth Semester

Civil Engineering

MG 1351 - PRINCIPLES OF MANAGEMENT

(Regulation 2004)

(Common to Aeronautical Engineering, Automobile Engineering, Biomedical Engineering, Civil Engineering, Electrical and Electronics Engineering, Electronics and Communication Engineering, Electronics and Instrumentation Engineering, Instrumentation and Control Engineering, Mechanical Engineering, Mechatronics Engineering, Metallurgical Engineering, Production Engineering, Information Technology)

Time: Three hours Maximum: 100 marks

Answer ALL questions

PART A – (10 x 2=20 marks)

1. What is systems approach to management?

2. Define Joint sector unit.

3. What are the elements of business forecasting?

4. What do mean by policy?

5. What do you understand by ‘over delegation’ and ‘under delegation’?

6. Define the term “Scalar chain”.

7. What is the difference between motivation and satisfaction?

8. What do you understand by non-verbal communications?

9. What is Multinational Corporation (MNC)?

10. What do understand by ‘flexi-budgets’?

PART B - (5 x 16= 80 marks)

11. (a) Discuss in detail about the various types of Business organization.

(b) (i) Explain the major characteristics of modern management thought. (10)

(ii) Compare Human relations theory and scientific management. (6)

12. (a) (i) Why planning is regarded as a primary function of management? Discuss the important

features and steps involved in planning process. (10)

(ii) Briefly discuss about strategic planning and operational planning. (6)

(b) (i) Elaborate the different types of organizational plans. (10)

(ii) What do understand by Management by objectives (MBO)? What are its advantages and

limitations? (6)

13. (a) (i) Describe a case in which matrix organization structure will be effective. Also discuss the

advantages and limitations of matrix organization. (10)

(ii) Compare formal and informal organizations. (6)

(b) (i) “Delegation is the ability to get result through others”—Discuss. Explain the steps and

guidelines to be followed while delegating authority. (8)

(ii) Explain the various methods of training. (8)

14. (a) (i) What do understand by “Leadership style”? Describe the different styles of leadership.

(8)

(ii) Explain why management by wandering around considered as effective communication.

What are the barriers to effective communication? (8)

(b) (i) Critically examine Maslow’s need priority model. How far up the hierarchical ladder do

most people progress? (10)

(ii) Discuss briefly how to enrich a job effectively. Outline the merits and demerits of job

enrichment. (6)

15. (a) (i) Discuss the importance of control in organization. Explain the steps involved in

controlling process. (10)

(ii) What are the different types of organizational control? Mention the advantages of using

budget as a control. (6)

(b) (i) Describe the major functions of computer and its role in handling information. (6)

(ii) Explain the concept of MIS and the stages involved in establishing MIS. (10)

2010-05-09T08:49:00.000-07:00

2009-11-14T09:42:00.001-08:00

PROGRAM:

%program for circular convolution

g=input('enter the first sequence');

h=input('enter the second sequence');

N1=length(g);

N2=length(h);

N=max(N1,N2);

N3=N1-N2;

%loop for getting equal length

if(N3==0)

h=[h,zeros(1,N3)];

else

g=[g,zeros(1,-N3)];

end

%computation of circular waves

for n=1:N;

y(n)=0;

for i=1:N;

j=n-i+1;

if(j==0)

j=N+j;

end

y(n)=y(n)+g(i)*h(j);

end

subplot(3,1,1);

stem(g);

ylabel('amplitude-->');

xlabel('g(n)-->');

subplot(3,1,2);

stem(h);

ylabel('amplitude-->');

xlabel('h(n)-->');

subplot(3,1,3);

stem(y);

ylabel('amplitude-->');

xlabel('y(n)-->');

disp('the resultant signal is:');y

2009-11-12T09:55:00.001-08:00

LINEAR CONVOLUTION

PROGRAM:

clc;

x=input('enter the first sequence');

h=input('enter the second sequence');

y=conv(h,x);

figure;

subplot(3,1,1);

stem(x);

ylabel('amplitude-->');

xlabel('a(n)-->');

subplot(3,1,2);

stem(h);

ylabel('amplitude-->');

xlabel('b(n)-->');

subplot(3,1,3);

stem(y);

ylabel('amplitude-->');

xlabel('c(n)-->');

disp('the resultant signal is');y

ECE Department

2009-11-12T09:30:00.000-08:00

This website consists of all the information likes question papers, Q & A, programs etc for ECE Department engineering students.

Now here are some list of digital signal processing programs for 5th semester ECE dept engineering students.

5th semester

Program:

%generation of the unit impulse signal:

t=-2:1:2;

y=[zeros(1,2),ones(1,1),zeros(1,2)];

subplot(2,2,1);

stem(t,y);

ylabel('amplitude-->');

xlabel('a(n)-->');

%generation of unit step signal:

n=input('enter the N value:');

t=0:1:n-1;

y1=ones(1,n);

subplot(2,2,2);

stem(t,y1);

ylabel('amplitude-->');

xlabel('b(n)-->');

%generation of ramp signal:

n1=input('enter the length of the sequence:');

t=0:n1;

subplot(2,2,3);

stem(t,t);

ylabel('amplitude-->');

xlabel('c(n)-->');

%generation of exponential signal:

n2=input('enter the length of exponential sequence:');

t=0:2:n2;

a=input('enter the a value');

y2=exp(a*t);

subplot(2,2,4);

stem(t,y2);

ylabel('amplitude-->');

xlabel('d(n)-->');

%generation of sine signal:

t=0:.01:pi;

y=sin(2*pi*t);

figure(2);

subplot(2,1,1);

plot(t,y);

ylabel('amplitude-->');

xlabel('d(n)-->');

%generation of cosine signal:

t=0:.01:pi;

y1=cos(2*pi*t);

subplot(2,1,2);

plot(t,y1);

ylabel('amplitude-->');

xlabel('e(n)-->