Frequency Control Solutions

New Application for harvests wasted energy from electronics- Piezoelectric Devices

noreply@blogger.com (Fox Electronics) — Fri, 17 Feb 2012 10:00:00 +0000

Piezoelectricity is generally referred the electricity resulting from pressure. It’s the charge that accumulates in certain solid materials in response to applied mechanical stress. Now, when we talk about piezoelectric effect, it is the interaction between the mechanical and electrical state in crystalline material. Piezoelectric materials are considered to be the high voltage and power sources. Direct piezoelectricity of some substances like quartz can generate potential differences of thousands of volts.

The global demand for piezoelectric devices is continuously increasing. The largest material group for these devices is piezocrystal, and piezopolymer is experiencing the highest growth due to its light weight and small size. Piezoelectricity proves to be helpful in various applications such as the production and detection of sound, generation of high voltages, electronic frequency generation and various others.

Currently, industrial and manufacturing is the largest application market for piezoelectric devices. These days, piezoelectric materials are used as the main functional materials for sensors and actuators in smart structures. The continued development of these materials has lead to huge market of products ranging from those of everyday use to more specialized devices. Piezoelectric sensors are used with high frequency sound in ultrasonic transducers for medical imaging and also industrial non destructive testing. The piezoelectric sensor applications are not just limited to this; these are widely used in detection and generation of sonar waves, power monitoring in high power applications, automotive engine management systems, etc.

To support the market, several piezoelectric manufacturers are available who can deliver high quality piezoelectric materials. In addition to this, they can also deliver engineering services including product design and development, testing and rapid prototyping of devices. There are manufacturers who specialize in meeting its customer’s precise custom requirements for piezoelectric ceramic products and piezo devices with processing capabilities. As per your requirements, you can surf the internet to find the suppliers who can caters to your business needs.

HCMOS 3.2 x 2.5mm 3.3V Oscillator

noreply@blogger.com (Fox Electronics) — Tue, 24 Jan 2012 12:38:00 +0000

Fox Electronics, a leading global supplier of frequency control solutions, recently released a new HCMOS in a compact 3.2 x 2.5mm 3.3V Oscillator for Ethernet applications.Here they offer wide range of crystal oscillator. In their line items they have introduced XpressO HCMOS oscillators. FXO-HC33 series has its special specification as a 3.3 volt and the dimensions are 3.2 mm x 2.5 mm package oscillators, and its stabilities is ±25 ppm with frequency range of 0.75 MHz to 250 MHz.

This oscillator has operation ability in temperature range of -20°C to +70°C or -40°C to +85°C. This oscillator is come with many features as Frequency Resolution to six decimal, tri state enable/disable feature, fully RoHS and REACH (Registration, Evaluation, Authorization, and Restriction of Chemicals) compliance. This XpressO HCMOS oscillators used in different applications like SONET, Ethernet, Storage Area network, test and measurement equipment and also for any application which requires oscillator. This Fox Oscillator is designed and developed with focus on noise reduction technologies.

Delta Sigma Modulator reduces noise to the levels that are comparable to other traditional Quartz and SAW oscillators. This XpressO HCMOS is Gold over Nickel Termination Finish provides the best conductivity which results in best performance of the application. By its low cost and extremely low jitter it becomes the best suited oscillator for the applications.

These XpressO HCMOS are ready to ship and samples are also available.

Equivalent Circuit

noreply@blogger.com (Fox Electronics) — Thu, 15 Dec 2011 06:28:00 +0000

An equivalent circuit refers to a theoretical circuit that maintains all of the electrical characteristics of a given circuit. It proves to be quite useful for making quantitative predictions about the behavior of the induction machine, under various operating conditions. Usually, an equivalent circuit is required to simplify more complex circuit in order to aid analysis. Usually equivalent circuits consist of linear elements; however complex circuits have non linear behavior.

The equivalent circuit shown above depicts electrical activity of a quartz crystal unit operating at its natural resonant frequency. The C_O, or shunt capacitance, represents the capacitance of the crystal electrodes plus the capacitance of the holder and leads. R₁, C₁, and L₁ compose the "motional arm" of the crystal, and are referred to as the motional parameters. The motional inductance (L₁) represents the vibrating mass of the crystal unit. The motional capacitance (C₁) represents the elasticity of the quartz, and the resistance (R₁), represents bulk losses occurring within the quartz.

Timing device manufacturer

noreply@blogger.com (Fox Electronics) — Wed, 16 Nov 2011 08:26:00 +0000

All measuring instruments are subject to varying degrees of errors and uncertain measurement. To prevent any such error, timing devices are used in electrical and electronics equipments. Timing device is an instrument that helps in measuring elapsed time intervals in hours, minutes, seconds and fractions of a second. These devices help in measuring time accurately in comparison to manual recording.

These devices are most commonly used in wristwatches, pocket watches, stopwatches and timers. Small timing devices are manufactured for pocket and wrist watches. However, large timing devices are used in table and panel-mounted units, including demonstrational timers. Timers work exactly like clocks and watches. They also have a basic mechanical, electrical or electronic movement for measuring time.

These devices are usually electrically powered, electromechanical or electronic with digital display. Timers work on a special mechanism. These devices start, stop and reset the indicator hands automatically thus allow the measurement of elapsed time intervals accurately. Several timing devices manufacturers are available in the market that can design fine quality timing devices measuring time, temperature and distance with precision. As these devices can be customized as per requirement, it can be availed to suit the necessities of the application.

Thru hole technology in crystal

noreply@blogger.com (Fox Electronics) — Mon, 10 Oct 2011 06:28:00 +0000

Through hole technology is usually used for the electronic components that involve the use of leads on the components that are inserted into the holes drilled in printed circuit boards either manually or by the use of automated insertion mount machines. This technology has almost replaced earlier electronic assembly techniques. The through-hole mounting provides strong mechanical bonds when compared to surface mount technology techniques. However, the drilling process required for through hole mounting makes the board more expensive.Thru hole crystal oscillators are usually installed in the applications where size is not a critical issue and where wide range of frequencies are required. It features simplest manufacturing process and have more desirable temperature and electrical characteristics than surface mount crystals. Also, through hole crystals are used in more demanding applications that surface mounting crystals.

The most commonly used industry wide standard package for a thru hole crystal oscillator is a 4-pin dip half size (Oscilent 320 Series) whereas the most common package for a surface mount device is 5x7mm Ceramic 4 pad device (Oscilent 430 Series). Thru hole mounting techniques are usually reserved for bulkier components such as electrolytic capacitor or semiconductors in larger packages such as TO220 that need the additional mounting strength.

Custom oscillators to meet exact requirements

noreply@blogger.com (Fox Electronics) — Mon, 19 Sep 2011 07:37:00 +0000

The increase in the demand for the oscillators in response to its tremendous usage in every electronic product has created vast business opportunities for oscillator manufacturers. The usage of oscillators in every electronic device has gained huge momentum in the past few decades. Ranging from quartz watch, AM radio transmitter, computers, and metal detectors to stun gun, these frequency control products are widely used in every electronic component.

There are various types of oscillators such as crystal oscillator (XO), voltage controlled crystal oscillator, temperature compensated crystal oscillator (TCXO), oven controlled crystal oscillator (OCXO), surface mount oscillators, etc. Each oscillator features different characteristic. It is very important for the client to understand specific relationship between oscillators before implementing them in the application. Some oscillators are suitable for one kind of application and entirely useless for another application. Therefore, one needs to be very careful while choosing the oscillator for the application.

Sometimes, it’s become quite difficult to avail the oscillators that meet the specific requirements of the application. In that case, the customer can contact oscillator manufacturers to get their frequency-related components designed and manufactured. The production and quality engineers of oscillators producing companies thoroughly implements quality procedures at every stage from product planning, designing, development and manufacturing to ensure high quality standards. These custom build oscillators are manufactured to suit the exact requirements of the client.

Oscillators for broad spectrum of applications

noreply@blogger.com (Fox Electronics) — Wed, 10 Aug 2011 08:48:00 +0000

There are several types of oscillators and each has its own characteristics and specific function to perform. That is why, it is very important to understand the specific relationship between various oscillators before implementing them in any application. Some oscillators are very accurate in certain situations and can be entirely useless in other condition.

Electronic oscillators have gain wide popularity nowadays. These oscillators are widely used in broad spectrum of applications. They are manufactured to suit a wide range of applications from low cost clock oscillators through to high-reliability oscillators. These oscillators have electronic circuit and produces repetitive electronic signals. On the basis of the output produced by these oscillators, they are divided into various types such as Voltage Control Crystal Oscillators, Xpresso Oscillators, Smd Oscillators, Temperature Control Crystal Oscillators, etc.

For example, if you are looking for high precision frequency control devices, Xpresso oscillators are the best option. However, VCXOs contains a network that’s by changing the voltage can change the output frequency. Therefore, the specifications and requirements should be clearly defined to get oscillator that caters to all your needs.

There are several oscillators’ manufactures who can guide you through the entire functionality to help you get the right oscillator for your application. Also, they provide technical support to their potential customers. Therefore, choosing right oscillator for your application is no more a difficult task anymore.

Importance of oscillators

noreply@blogger.com (Fox Electronics) — Thu, 14 Jul 2011 19:02:00 +0000

Oscillator is basically considered to be a technical indicator that is used to generate repetitive signals. In technical terms, one can say that the oscillator contains a path where the part of the output signal is fed back to generate input signal. Or, we can say that oscillators have the capacity to produce output signals without an input signal.

On the basis of the output signals produced by oscillators, they are basically categorized into two classes, namely harmonic oscillators and relaxation oscillators. And the most common type of waveform produced by oscillators is sinusoidal and square.

They come in various packages and each has its own functionality and characteristics to offer. Therefore, you should be quite careful while selecting oscillators. Oscillation is the periodic variation and people often consider similar to vibration. Oscillation is a process that not only exists in the physical world but in biological world as well.

The usage of oscillators has increased steadily. Nowadays, they are commonly found in almost all electronic, most commonly in everyday circuits. The basic feature of the oscillators to generate oscillating output is used to generate signals in electronic products. Various outputs that can be produced by oscillators are square, sine, sawtooth, triange or complex waveform.

Usability of piezoelectric effect

noreply@blogger.com (Fox Electronics) — Thu, 23 Jun 2011 10:55:00 +0000

Some materials are capable of producing electricity when subjected to mechanical stress and this effect is known as piezoelectric effect. To produce this stress, it is not necessary to fracture the crystal lattice, hitting or twisting the material is just enough to deform the crystal lattice. However, this effect also works in the opposite direction with the material deforming slightly when electric current is applied. Piezoelectricity was discovered more that hundred years and today there are several applications that use piezoelectric effect. Electronic clocks, inkjet printers, gas ovens and other scientific instruments that require extremely precise movements use this effect.

When the charge within the crystal lattice of a material gets disturbed, it helps to generate piezoelectric effect. When no stress is being applied on the material, the positive and negative charges are distributed in an evenly manner so there is no potential difference. But when the pressure is applied, the lattice is changed slightly and creates an imbalance to generate potential difference, often as high as several thousand volts. However, the current which is generated is extremely small and can only cause a small electric shock.

Piezoelectric crystals are used in various applications. They are used in several gas-powered appliances. They are used in electronic clocks and watches to maintain time. Clocks powered by these crystals are known as quartz clocks. These crystals are basically made from quartz that has the natural frequency that is ideal for creating the oscillations needed to maintain exact time.

The flow of data in computers can also be organized with the help of quartz crystals. Thin speakers inside wristwatches also use disc of piezoelectric materials. In addition to this, piezoelectric effect is also being used in solving computer problems that are related to over clocking. It is very helpful in over clocking graphic cards in the computer ports of the laptops. Most of the software and hardware manufacturer make use of piezoelectric effect in their products in order to enhance the performance of computer systems.

The natural frequency of quartz crystal made them ideal for creating the oscillation in which exact time is required. Sonar transducers apply an electrical pulse to a piezoelectric crystal to generate a pressure wave which creates a current when the reflected wave deforms the crystal. And the time taken between the two currents is basically used to work out how far an object is. Industrial inkjets is the commonest example using this process. There are several products that make use of the principle of piezoelectric effect to enhance the performance.

Oscillators for electronic devices

noreply@blogger.com (Fox Electronics) — Mon, 13 Jun 2011 09:03:00 +0000

Oscillators are the device used to generate repetitive signals. They can produce output signals without an input signal. They are basically a type of technical indicator that comes in various packages offering specific function and unique characteristics. Therefore selecting an oscillator that suits your needs and is compatible for your application is quite essential.

There are wide varieties of oscillators available in the market that offers various characteristics which trader needs to be aware of when buying oscillators. It is very important for trader to understand specific relationship between oscillators before implementing them in your application. Some oscillators are suitable for one kind of application and entirely useless for another situation. Oscillator usage can prove to be quite useful provided trader should be completely aware of the flaws and benefits of the oscillator.

Oscillators are also categorized on the basis of output they produce. They have gain huge momentum in the past few decades as they are used in almost all electronic devices ranging from radio and television transmitters, clock signals that regulate computers, quartz clocks to many electronic devices. As the manufacturer of electronic devices, I always prefer to go my regular supplier.

Fox Electronics has never let me down and catered to my toughest frequency control needs. Moreover, they also offer technical support to resolve all the issues that I face while choosing oscillators for the devices and make me understand the features of oscillators thereby offering the ease of choosing the right oscillator to suit my needs.

Xpresso Oscillators for Gigabit Ethernet and Fibre Channel Applications

noreply@blogger.com (Fox Electronics) — Mon, 16 May 2011 06:20:00 +0000

Fox Electronics is the leading global supplier of frequency control solutions that can cater to all your needs related to crystals, fixed and configurable oscillators, TCXOs, VCXOs, etc. With the necessity to introduce something new Fox Electronics has introduced a line of Xpresso oscillators

explicitly designed to meet the needs of Gigabit Ethernet (GbE) and 10 GbE applications. It also offers Xpresso oscillators optimized uniquely for fibre channel configuration. Each model in Xpresso specific application line is pre-configured to meet application specific requirements in an industry.

The Xpresso crystal oscillator is a breakthrough in configurable frequency control solution which utilizes a family of proprietary ASICs and works on the key technologies of noise reduction. Due to the enhanced features of low jitter, multiple frequencies, small package size and output options at a low price, gives it an edge over others.

XOs for Gigabit Ethernet and 10 GbE applications

Each model in this application specific model is preconfigured to meet precise application specific requirements. The series is introduced with the motive to combine Fox’s patented breakthrough Xpresso technology with the specific characteristics required to meet the demanding needs of 3.3-volts Ethernet specific applications to make sure that it delivers the best performance without spending your precious time associated with custom products. This technology bids fast delivery of low jitter, small package size and output options at a low cost.

Fox's Ethernet specific XO oscillators offer frequency stability of ±50 ppm and with tighter stabilities can be made available upon demand. They are also obtainable in 125.00 MHz, 156.25 MHz and 312.50 MHz models.

XO for Fibre channel

Fox Electronics new line of application specific XO oscillators optimized for fibre channel configurations are off-the shelf and pre-configured to meet precise application specific requirements in an industry 7mm x 5 mm package. Having the same characteristics of fast delivery of low jitter, small package size and multiple frequencies, its distinctiveness can meet the demanding needs of specific fibre channel applications without the wait associated with custom products.

These oscillators offer a frequency stability of ±50 ppm and are available in 106.25 MHz, 159.375 MHz and 212.50 MHz models. Moreover, they also comes with tri-state enable/disable feature, thereby facilitating the users to turn the output on and off.

Both of these, application specific oscillator model features an operating temperature range of -40°C to +85°C and a storage temperature range of -55°C to +125°C.

Understanding Electronic Oscillators

noreply@blogger.com (Fox Electronics) — Mon, 11 Apr 2011 07:07:00 +0000

Oscillators are used almost in all electronic devices such as computers, receiver, transmitters, audio frequency equipments, etc. They are basically used to generate signals. Different types of oscillators are available in the market; however same principle drives them all. Every oscillator consists of an active device which is known as amplifier. This sensitive amplifier is used in the oscillator to produce certain output. This output is supplied back to input in phase which further help in regenerating and sustaining the signal.

To understand the concept of oscillator, there is none other than the commonest example of pendulum of a clock. Whenever a pendulum is set in motion, it begins swinging and oscillating at a particular frequency. Apart from this, the length of the oscillator is also a factor in determining the frequency of an oscillator.

Oscillator makes use of energy to move back and forth. The transformation of energy causes oscillation in the pendulum. For example in case of pendulum, the potential energy gets converted in to kinetic energy which leads to oscillation. However, any physical force can stop oscillator’s physical movement. Even, electronic oscillators are designed to work on the same principle.

Electronic oscillators are basically categorized into two, namely harmonic oscillators and relaxation oscillators.

Harmonic oscillators: These types of oscillators are used in the components where sinusoidal waveform needs to be generated. Amplifier in harmonic oscillators delivers gain and a resonant circuit supply a back signal to the input. Oscillation occurs at resonant circuit where gain takes place around the loop. Crystal oscillators and LC-tank oscillators are some of the examples of harmonic oscillators.

Relaxation oscillators: These types of oscillators generate triangular waveform that is usually used in monolithic integrated circuits. Relaxation oscillator helps to get operational frequencies with least number of external components. These types of oscillators are also categorized into three topologies, namely grounded-capacitor VCOs, emitter-coupled VCOs and delay-based ring VCOs.

Why TCXO is preferable over standard crystal oscillator?

noreply@blogger.com (Fox Electronics) — Wed, 09 Feb 2011 10:13:00 +0000

A crystal oscillator is an electronic oscillator circuit that draws on the mechanical resonance of a vibrating crystal of piezoelectric material. Crystal oscillator is the best option, in case you are looking forward to generate an electrical signal with a specific frequency. This type of frequency is basically required for maintaining track of time. It is used in digital integrated circuits to get constant clock signals and to stabilize frequencies in radio transmitters and receivers. The quartz crystal is most commonly used piezoelectric resonator which is why the oscillator circuits designed using quartz crystal are known as crystal oscillators.

There are several factors that can affect the resonant frequency of a quartz crystal including environmental changes such as temperature, pressure, humidity, etc. However, there are certain designs that have the minimum effect of environmental changes on them. Some of these designs comprise of TCXO, , and OCXO. In this article, I am giving some brief introduction on TCXOs which can help you to understand this design better.

Temperature compensated crystal oscillator is often referred to as TCXOs. It features tremendous temperature characteristic with low power consumption and speedy heat up. That’s why it is considered to be highly temperature-stable device at a given temperature. Moreover, there are certain models of TCXOs available in the market that allows and facilitates the user to adjust the frequency through external control voltage.

The basic importance of TCXO is that it can deliver tremendous temperature stability within a compact, light-weight and low power device. There are several applications for which TCXO is an ideal design such as telecommunication equipment including mobile telephone, microwaves, satellite communication technologies, etc.

Here’s an overview of TCXO design features that differs it from basic crystal oscillator design:

•Delivers precise frequency and reduced long term aging

•Prone to external changes in the circuit
•Integrated with internal regulator to lessen the effect of changes in voltage

Because of the admirable features of a TXCO, it is preferable to standard crystal oscillator.

Temperature Control Crystal Oscillator - TCXO Technology: A Perspective

noreply@blogger.com (Fox Electronics) — Sat, 20 Nov 2010 06:50:00 +0000

A TCXO (Temperature Control Crystal Oscillator) is a voltage controlled crystal oscillator with a improvement voltage apply to the voltage control pin. This voltage changes with temperature to bring the frequency back to nominal.

Temperature compensated crystal oscillators (TCXOs) offer excellent temperature characteristics with low power consumption and fast warmup. Most models of TCXOs also offer a facility to adjust the frequency by means of an external control voltage. They do not offer as wide a pulling range as a VCXO.

Any crystal related problems such as coupled modes cannot be improved for and are superimposed on the resulting frequency-temperature curve. This makes the design and manufacturing of the crystal a difficult and critical part of the TCXO. The majority of TCXO’s require a voltage control function. This allows for exact setting of frequency, adjustments for long-term aging and the ability to phase lock the device to other sources. This function VCTCXO, works by adjusting the load capacitance presented to the crystal. The changes made by these adjustments should be taken into account for fixed tolerance TCXO’s.

The capacitors used to adjust frequency have a temperature coefficient, and this temperature coefficient changes the nominal value of the capacitors over temperature. This change has an effect on the compensation of the crystal. In lower precision TCXO’s this is usually ignored, but as TCXO precision meets and exceeds 0.5 ppm levels, these effects can no longer be ignored. In a typical application the units will need to be adjusted from 0.5-2 ppm for exact calibration. The device will then need adjustment for long term stability.

New Miniature Tuning Fork Crystal from Fox is 33% Smaller to Fit Wide Range of Applications

noreply@blogger.com (Fox Electronics) — Thu, 18 Nov 2010 08:26:00 +0000

Fox Electronics, a leading global supplier of frequency control solutions, recently increased its range of watch crystals with a new tuning fork. The FX122 is approximately 33% smaller than previous models, measuring just 2.1 mm x 1.3 mm with a very low profile of 0.6 mm.

The miniature size of the new FX122 watch crystal makes it ideal for portable and handheld devices where space is critical. With a frequency of 32.768 kHz, the new surface mount device (SMD) is optimized for a standard 12.5 pF load capacitance, with an optional load capacitance of 9 pF available.

Frequency tolerance is ±20 PPM at 25°C (77°F) and frequency stability is -0.04 ppm / (change in C°)2 over the standard operating temperature of -40°C to +85°C (-40°F to 185°F).Turnover temperature range is +20°C to +30°C (68°F to 86°F) and storage temperature is -55°C to +125°C (-67°F to 257°F).

Maximum equivalent series resistance of the new FX122 crystal is 90 k ohm and insulation resistance is 500 megaohm at 100 VDC. Aging is ±3 PPM per year. The termination finish is gold over nickel.The new watch crystal is RoHS-compliant and comes standard in a 3,000-unit tape and reel for automatic assembly systems.

Advantages and Disadvantages of Oven Controlled Crystal Oscillators-OCXOs

noreply@blogger.com (Fox Electronics) — Mon, 04 Oct 2010 10:17:00 +0000

The main advantage of an OCXO is its stability, which is unparallel by other crystal oscillator types. The frequency against temperature stability of an OCXO depends on the static and dynamic F vs. T characteristics of the resonator, the design temperature range of the OCXO, the stability of the oven and of the components in the sustaining circuitry, and the accuracy with which the oven is set to the turnover temperature of the resonator. Typical fractional stability can range from ± 20 ppb (±20E-9) to ±100 ppb. This stability can be valid for a temperature range of –40 degree C to + 85 degree C. Improved stability can be obtained over narrow temperature ranges.

The main drawback of an OCXO is power eating, unit size, warm-up time and cost. The amount of oven power required is determined mainly by the quality of insulation used and the temperature differential between the oven and the external environment. Increasing amount of insulation to reduce heat loss requires an increase in size, resulting in a tradeoff between power and size. Warm-up time is the time required for the oven to reach operating temperature and for the frequency to stabilize. It is largely dependent on available power, the thermal mass of the oven, the quality of insulation, and ambient temperature. Typical warm-up times are from 15 seconds to 5 minutes.

The OCXO operating temperature is required several degrees higher than the highest ambient temperature in which OCXO has to operate by which the oven may maintain good control. There are disadvantages associated with high oven temperature operation. First, the crystal’s frequency vs. temperature characteristic is sharper with the higher turnover crystal. Second one is more important, crystal aging degrade with an increasing temperature. That’s why it is important while designing an OCXO. It should be low as practicable, but it must be high to drive good control at the maximum ambient operating temperature.

Fox Expands Facility, Sales Force and Technology Presence Around the World

noreply@blogger.com (Fox Electronics) — Mon, 20 Sep 2010 10:23:00 +0000

Fox Electronics, a leading global supplier of frequency control solutions, recently announced the relocation and expansion of the Fox Electronics Asia headquarters in Hong Kong to better facilitate the demand of the company's products in the area. In addition to the expanded headquarters, Fox Electronics Asia has also expanded engineering, sales support and logistics support to better serve its Asian customers.

"The expansion of our location and service capabilities is due in large part to the increasing market acceptance of our patented XpressO technology," states Herb Chaney, Vice President and Managing Director, Fox Electronics Asia Ltd. and Fox Electronics EMEA. "The company has been able to grow substantially in the region, and around the world, thanks to the burgeoning-demand for our XpressO product line that has revolutionized configurable frequency control solutions."

In August 2010, Fox and XpressO reached the milestone of shipping out 10 million XpressO oscillators. Fox's XpressO crystal oscillators are a low jitter, low cost oscillator line delivered fast and available in a wide variety of sizes, standard and custom frequencies, package types and designs. XpressO oscillators are now also available in application specific configurations.

The company has also announced the introduction of Mr. Paul Rodger to the Fox Electronics family as Director of Sales and Marketing, Fox Electronics EMEA. The appointment was made effective June 1, 2010. Rodger brings his 20 years of EMEA sales and marketing experience from the semiconductor marketplace to Fox. He and the rest of the EMEA team will continue to support the company's customers in the Europe-Mideast-Africa region from Fox's current UK office.

The new Fox Electronics Asia, Ltd. office will continue to use the same telephone number, fax number, email addresses and mobile numbers. The new office is located at

21/F, Cheong Sun Tower

118 Wing Lok Street

Sheung Wan, Hong Kong

(P): 852-2854-4285

(F): 852-2854-4282

Paul Rodger can be reached in the office directly starting June 15, 2010 at +44-1283-568153 +44-1283-568153 via his mobile at +44-7786-516052 +44-7786-516052 or via email at Paul.Rodger@foxonline.com. For regular mail correspondence, the Fox Electronics EMEA office can be reached at

9 Alderson Drive

Stretton, Burton Upon Trent

Staffs. DE13 0QQ

United Kingdom

For more information, please visit http://www.foxonline.com or contact Customer Service, Fox Electronics, 5570 Enterprise Parkway, Fort Myers, Fla. 33905.

Oscillator Drift and Frequency Stability

noreply@blogger.com (Fox Electronics) — Fri, 03 Sep 2010 06:58:00 +0000

Oscillator drift can be associated directly to frequency stability. Drift is the unwanted change in frequency measured over seconds, minutes or hours.

In the world of electrical engineering and specifically in telecommunications, frequency drift is an unplanned and uniformed offset of an oscillator from its nominal frequency. It happens due to change in temperature, which alert the piezoelectric effect in a quartz crystal or due to the voltage regulator problem which is responsible for the bias voltage to the oscillator.

I guess you might have experienced on a radio transmitter, frequency drift can cause a radio station to drift into an adjacent channel, causing illegal interference. Due to this, there are typically regulations specifying what type of tolerance such oscillator must have. A temperature compensated voltage controlled oscillator is used for FM.

On the receiver side, frequency drift was mainly a problem in early tuners, mainly for analog and dial tuning, and especially on FM, which exhibits a capture effect.
However, the phase locked loop essentially eliminates the drift issue. For transmitters, a numerically controlled oscillator also does not have problems with drift.

It is different from Doppler shift, which is a perceived difference in frequency, even though the source is still producing the same wavelength, because the source is moving. It also differs from frequency deviation, which is the natural and necessary result of modulation in both FM and phase modulation.

Sources of oscillator drift:

• Thermal instability causing oscillator drift
• Thermal instability of inductors

Suggested cures for oscillator drift are underneath:

• Use quality components for the application
• Use the best inductor possible
• Use the best regulated power supply at the lowest voltage possible
• Make sure your oscillator is "well buffered" to minimize oscillator drift
• Mechanical stability has an effect on oscillator drift
• Shielding and heat sinking

Standard Guidelines for Constant Electrical Parameters of Quartz Crystals

noreply@blogger.com (Fox Electronics) — Wed, 04 Aug 2010 07:20:00 +0000

Normally, Quartz Crystals are manufactured according to industry standard guidelines.

1. Mode of Operation
2. Equivalent Series Resistance
3. Shunt Capacitance and
4. Drive Level.

Above given parameters may vary slightly between manufactures.

1. Mode of Operation (Resonance Frequency):
A Quartz Crystal has two basic modes of operation comprising Fundamental and Overtone Modes. For frequencies below 30MHz, a crystal manufacturer will use the Fundamental Mode of operation. For frequencies exceeding 30 MHz, overtone modes are suggested. Using Overtone Modes in production therefore reduces manufacturing costs for higher frequency applications. A good rule of thumb is to assume the a Crystal manufacturer will produce a Fundamental Crystal below 30MHz, and an Overtone Crystal above 30MHz. If higher frequencies are required in the Fundamental Mode, please contact FOX ELECTRONICS.

2. Equivalent Series Resistance (ESR):
The Equivalent Series Resistance is the resistive element of the quartz crystal equivalent circuit. This range is normally found to be 25-100 ohms for most Quartz Crystals and is usually specified as a maximum value. Typically, these values are specified according to frequency ranges and are very similar across multiple manufactures because similar holder types, electrodes, modes of operation, and mounting structures are used in achieving specific frequencies. Point to be noted that ESR values at a given frequency for an AT-strip cut crystal and it is commonly used in SM devices.

3. Shunt Capacitance:
The electrodes present in a Quartz Crystal, plus the stray capacitance of the holder, form a capacitance in parallel with the LC model. Generally, the Shunt Capacitance is required to be as low as possible in manufacturing the device, as some oscillators cannot tolerate an excessive value. Because Shunt Capacitance may vary according to the size of the Crystal, manufacturers will normally designate a maximum value usually at 7.0pF. If a lower value is required, we suggest contacting FOX Engineering Support.

4. Drive Level:
Specified by Quartz Crystal manufacturers to provide a guideline for maximum values, the Drive Level should be held to a minimum to avoid problems with Aging, Stability, nonlinear coupled modes, and other nonlinear effects. Improvements in phase noise performance can be realized with increased drive levels; however, so careful consideration should be given to this Electrical Parameter when approaching the maximum suggested level.

Expansion at Fox Hong Kong

noreply@blogger.com (Fox Electronics) — Tue, 03 Aug 2010 07:25:00 +0000

Fox Electronics is happy to announce the relocation and expansion of its Asia Pacific Headquarters office effective August the 16th, 2010.

Herb Chaney, Vice President and Managing Director Fox Electronics Asia Ltd., and Fox Electronics EMEA further comments "Our relocation and subsequent expansion of all service areas has been driven due to our substantial growth in the region centered around our revolutionary product family XpressO. With the continued growth and demand of all Fox Products we will be able to better serve our customers with expanded Engineering, Sales Support and Logistics Support". Our new office location will be:

Fox Electronics Asia Ltd.

21/F, Cheong Sun Tower

118 Wing Lok Street

Sheung Wan, Hong Kong

Fox Electronics Asia Ltd., telephone and fax numbers will remain the same.

Primary number is 852. 2854.4285 and our fax number is 852.2854.4282.

All other communication data such as email addresses and associates mobile numbers will remain the same.

Manufacturing Steps of a Quartz Crystal

noreply@blogger.com (Fox Electronics) — Wed, 07 Jul 2010 05:51:00 +0000

Quartz is the second richest mineral in the earth’s continental crust. It is made up of a continuous framework of SiO₄ silicon-oxygen tetrahedral. This quartz is used in our electronic circuit by which we produce Crystal Oscillator, which is being used in our different electronic devices like timing circuit, watches, etc. Here we are going to discuss the procedure how to manufacture a Quartz Crystal. There are some steps:

Cutting
Lapping
Finishing
Quality Control

Let’s discuss about these above mentioned points:

Cutting

The cutting operation is the first process performed on the quartz bar. The bar is sliced with special wafering machines into small square dice. The angle at which the dice are cut is very important for the overall performance of the finished crystals. Special X-ray units are used to assure the proper angle of cut in relation to the atomic planes.

Lapping

The quartz dice, called "blanks," cut from the "mother stone," now undergo lapping on precision lapping machines. A progressively finer finish on the major surfaces of the blanks is achieved as the crystals are lapped, first on one machine, then onto another. As the lapping operation reduces the thickness of the blanks, the frequency of the crystals is increased. Proper control of the lapping machines will result in the production of crystals with extremely accurate frequencies.

Finishing

After the quartz blanks have been lapped to a thickness which will yield the desired frequencies, they are thoroughly cleaned and metal electrodes are vacuum deposited on their two major faces. The electrodes pick up the electrical impulses which exist on the crystal surface and direct them to springs. The springs, in turn, pick up the electrical impulses and, in addition, help support the crystal to its mounting base.

A final frequency adjustment is made after the crystal has been mounted. Additional metal is vacuum deposited on each crystal. The final step is to seal the crystal hermetically by welding a metal can to its base, in order to protect the fragile blank from damage by moisture, air, handling, etc.

Quality Control

In process quality control, at various manufacturing steps, ascertains favorable production yields. Before the finished units are released, they are thoroughly tested at a Quality control station where paramount attention is given to stable crystal frequency over a temperature range from as low as -55 degree Centigrade to 125 degree Centigrade. The "activity" of the crystal is checked as it indicates how strongly the crystal is vibrating, and a "leak test" is performed in order to assure that the crystal is hermetically sealed from its environment in order to preclude degradation of the unit.

New Fox Application Specific XpressO Oscillators Optimized for Gigabit Ethernet Configurations

noreply@blogger.com (Fox Electronics) — Wed, 07 Jul 2010 05:46:00 +0000

Fox Electronics, a leading global supplier of frequency control solutions, recently announced a new line of XpressO oscillators explicitly designed to meet the needs of Gigabit Ethernet (GbE) and 10 GbE applications. Each model in the new Application Specific XpressO line is off-the-shelf, pre-configured to precise application-specific requirements in an industry standard 7 mm x 5 mm package.

The series is the first to combine Fox's patented breakthrough XpressO technology with the specific characteristics required to meet the demanding needs of 3.3-volt (±5% standard) Ethernet-specific applications to ensure the best performance possible without the wait associated with custom products. XpressO technology offers fast delivery of low jitter, small package size and multiple frequency and output options at a low cost. Designed and developed by Fox, XpressO oscillators utilize a family of proprietary application specific integrated circuits (ASICs) with a key focus on noise reduction.

Fox's new Ethernet specific XO oscillators offer a frequency stability of ±50 ppm, with tighter stabilities available upon request and are available in 125.00 MHz, 156.25 MHz and 312.50 MHz models. HCMOS, LVPECL and LVDS outputs are available on the 125.00 MHz and 156.25 MHz models while LVPECL and LVDS outputs are available on the 312.50 MHz model. The XpressO oscillators offer a tri-state enable/disable feature, allowing the user to turn the output on and off. Output enable/disable time is less than 100 nS.

Each XpressO crystal oscillator model features an operating temperature range of -40°C to +85°C and a storage temperature range of -55°C to +125°C. At 12 kHz to 20 MHz, typical phase jitter is 0.75 pS RMS for the 125.00 MHz model, 0.77 pS RMS for 156.25 MHz and 0.86 pS RMS for 312.50 MHz. Start up time is 10 mS. The new XpressO oscillators feature gold over nickel termination finish.

For more information, please visit http://foxonline.com/xpresso_assp.htm or contact Customer Service, Fox Electronics, 5570 Enterprise Parkway, Fort Myers, Fla. 33905. Tel: 888-GET-2-FOX; Fax: 239-693-1554; E-mail: http://www.foxonline.com/email.htm; Web: www.foxonline.com. For an electronic copy, please visit http://www.simongroup.com/PressRoom/WordDocs/fox/FOX-A-3740.doc

Paul Rodger Joins as Director of Sales and Marketing at Fox Electronics

noreply@blogger.com (Fox Electronics) — Tue, 15 Jun 2010 05:37:00 +0000

Fox Electronics is pleased to announce the appointment of Mr. Paul Rodger as Director of Sales and Marketing Fox Electronics EMEA effective June the 1st 2010. Paul comes to Fox Electronics with more than 20 years of sales and marketing experience in the Semiconductor EMEA marketplace including experience as a Product Manager for several leading Semiconductor organizations.

Paul will be available at the Fox EMEA office on June the 15th.

To reach Paul by regular mail correspondence the Fox Electronics EMEA address is as follows: 9 Alderson Drive, Stretton, Burton Upon Trent. Staffs. DE13 0QQ. UK.

Paul and the rest of the Fox team are here to support your efforts and we kindly thank you for your support. Please join me in welcoming Paul to the Fox team and call upon him for all your needs.

Advantages and Disadvantages of the SC-Cut Crystals

noreply@blogger.com (Fox Electronics) — Tue, 15 Jun 2010 05:21:00 +0000

Advantages of the SC-cut crystals:

Improved aging – For a given frequency and overtone (e.g. 10 MHz, 3^rdovertone), the SC-cut crystal provides 2 to 3 times aging improvement relative to AT-cut.
Thermal transient compensated - Allowing faster warm-up in OCXOs
Phase noise – For a given oscillator design for a particular crystal frequency and overtone, the SC-cut crystal provides higher Q and associated improved phase noise characteristics.
Planar stress compensated - Smaller changes in frequency due to edge forces and bending
Far fewer activity dips
Lower drive level sensitivity
Lower sensitivity to radiation

Drawback of the SC-cut crystals:

Cost - Because of difficulties associated with tightly-controlled angle rotations around two axes in the manufacture of SC crystals vs one axis for the AT, the SC crystal is significantly higher in cost than that of an AT of the same frequency and overtone.
Pull ability - The motional capacitance of an SC crystal is several times less than that of an AT of the same frequency and overtone, thus reducing the ability to "pull" the crystal frequency. This restricts the SC crystal from being used in conventional TCXOs and VCXOs, or even in oven controlled oscillators requiring the ability to deviate the frequency of oscillation by any significant degree.
The suitability of double rotated crystals for use in crystal oscillators is essentially restricted to those oven controlled applications where the improved aging, warm-up, and close-in phase noise characteristics justify a significant cost increase.

Why Temperature Compensated Crystal Oscillator (TCXO)?

noreply@blogger.com (Fox Electronics) — Mon, 03 May 2010 11:55:00 +0000

A TCXO adjusts the frequency of the oscillator to compensate for the changes that will occur as a result of temperature changes. To achieve this, the main element within a TCXO is a Voltage Controlled Crystal Oscillator. This is connected to a circuit that senses the temperature and applies a small correction voltage to the oscillator.

The temperature sensing and compensating network may take a variety of forms these days. The traditional method was to use a thermistor network. More recently digital techniques such as Digital Signal Processing have been used to enable highly accurate compensation to be achieved.

The problem with applying the temperature compensation in a TCXO is that the temperature coefficient of the crystal changes with temperature, and it is not linear. As a result the design of the compensation network is complicated.

Moreover TCXOs normally have an external adjustment to enable the frequency to be reset periodically. This enables the effects of the ageing of the crystal to be removed. The period between calibrations adjustments will depend upon the accuracy required, but may typically be six months or a year. If we need very high levels of accuracy then we have to decrease the period of replacement of a
Crystal.