Replies: 13
Views: 231
Last Post By: migueljds ON: Thu Jan 26, 2017 10:56 am
Topic By: migueljds ON: Thu Jan 26, 2017 10:56 am
@aclassifier Yes, your old links will still work. The only thing that will change is /forum/ path dissappears.
ie. http://www.xcore.com/forum/viewtopic.php?f=27&t=5156
becomes http://www.xcore.com/viewtopic.php?f=27&t=5156
but I will put redirects in place on xcore.com so that you won't have to change your links.
And the projects and groups will redirect to their new location within the forum, so no external links will need to be changed

@Gothmag It's possible to view the active topic and recent topics using the quick menu in the top left, just below the logo. But I will look at putting in a right-hand column on the front page and putting the active and recent topics there instead, so that it's immediately visible.

Replies: 1
Views: 17
Last Post By: johned ON: Thu Jan 26, 2017 10:32 am
Topic By: johned ON: Thu Jan 26, 2017 10:32 am
Hi Shailesh,

Using an adaptive filter is quite a complex operation so first off I would refer you to a number of references :
https://www.google.co.uk/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=adaptive+filter+introduction

Specifically, to answer your questions. The filter will adapt to the reference sample. So for example if you are playing audio out of loudspeakers then this is your reference. Depending on your specific application you should not need to train it with a known signal. If your application requires this then a broadband signal is much better than a narrow band sinusoid.

Choosing the value of mu is the subject of many research papers and there is no simple answer. I would start with the values in the lib_dsp app note and see how you get on.

Best regards,
John

Replies: 1
Views: 19
Last Post By: colin ON: Thu Jan 26, 2017 10:22 am
Topic By: colin ON: Thu Jan 26, 2017 10:22 am
Hello Jose,

Perhaps the best board to start with is the slicekit (https://www.xmos.com/support/boards?product=15825) with the following additional slices:

https://www.xmos.com/support/boards?product=15833
https://www.xmos.com/support/boards?product=15827

Hopefully these give you all the necessary components to get started. It is possible, though I don't know for certain that those slices may also work with the latest XS2 slicekit (https://www.xmos.com/support/boards?product=19745). I will try and find out for you and let you know soon.

Best Wishes
Colin

Replies: 5
Views: 51
Last Post By: OscarMa ON: Thu Jan 26, 2017 10:04 am
Topic By: OscarMa ON: Thu Jan 26, 2017 10:04 am
Yes, after the incremental build of the configuration 1i2o2_xvsm2000, the clean all seems to fail.




This is the Console message:


16:35:25***Incremental build of configuration 1i2o2_xvsm2000 for project app_usb_aud_mic_array

xmake XVSM=1 CONFIG=1i2o2_xvsm2000 all
Checking build modules
Using build modules: lib_mic_array(2.0.1) lib_logging(2.0.1) module_dfu module_i2c_shared module_i2c_single_port module_usb_audio module_usb_device module_usb_midi module_usb_shared module_xud lib_voice(0.0.3) lib_device_control(2.0.0) lib_xvsm_support(0.4.3) lib_xassert(2.0.1) module_locks module_queue
Analyzing interrupt.c
xcc: >: Invalid argument
xmake[1]: *** [.build_1i2o2_xvsm2000/src/extensions/interrupt.c.pca.xml.decouple] Error 1
xmake: *** [analyze] Error 2

16:36:50 Build Finished (took 1m:24s.287ms)

Replies: 3
Views: 36
Last Post By: Choughtosh ON: Thu Jan 26, 2017 9:58 am
Topic By: Choughtosh ON: Thu Jan 26, 2017 9:58 am
Hi,

You can find details on the IO speed in the relevant datasheets.

thanks,

Rob

Replies: 3
Views: 36
Last Post By: andrew ON: Wed Jan 25, 2017 10:10 pm
Topic By: andrew ON: Wed Jan 25, 2017 10:10 pm
If you are comfortable working in the frequency domain and this suite your needs then we have optimised libraries for FFT, windowing, etc. We would not be able to support a time domain implementation of 8 FIRs at 2048 taps at 96kHz, but a block based implementation is very possible. Currently some of out internal (unreleased) code is doing 8 channel FIRs of 2048 taps but at 16kHz using overlap-and-add in a single thread. It would be easy to spread this technique across many cores if desired.

Replies: 0
Views: 13
Last Post By: aclassifier ON: Wed Jan 25, 2017 8:58 pm
Topic By: aclassifier ON: Wed Jan 25, 2017 8:58 pm
Is there any possibility to get system time before each line of printf lines?

This could be tagged on in the Preferences window.

Or will this slow the log, and thus make time tagging irrelevant?

Or is there any other way to do it?

Replies: 3
Views: 36
Last Post By: andrew ON: Wed Jan 25, 2017 10:10 pm
Topic By: RitchRock ON: Wed Jan 25, 2017 8:32 pm
Hi Andrew, thanks for the reply! Getting I2C to program the chip wasn't too difficult, but I did need to change the I2C address given in the TI datasheet to it's "7-bit version" for everything to play nice. This was a bit of a head scratcher for a few hours :).

Ideally I would like to support sample rates of 44.1k, 48k, 88.2k and 96k. The device needs to stream 4 filtered audio channels from my ADC to USB in, while at the same time sending these same 4 filtered streams to a DAC for analog out. The implementation may change, as I may be able to get away with less filtering, but at most, the DSP (or XMOS?) would process the 4 ADC channels with 2 FIR filters each (8 total) and apply a matrix. These FIRs are not the same, but can be the same length (2048).

Likely, there will be 2 additional channels output for headphone playback from the computer via USB. I may want to also filter this stereo playback.

In addition, I hope to read an encoder that programs the ADC PGAs, and perform audio mixing and level. There would also be a few LEDs to flash :). I'm not sure how many cores all this will take, or how many will be left over, but it seems to me that an external DSP may be in order. Any suggestions would be welcome.

Regarding filter implementation, years ago I created a convolution reverb using the overlap-add method, but there may a quicker way to do the processing on XMOS.

Cheers and thanks for your advice!

Replies: 6
Views: 60
Last Post By: larry ON: Wed Jan 25, 2017 6:54 pm
Topic By: larry ON: Wed Jan 25, 2017 6:54 pm
I see what the problem is now. Your processing is block based and USB is essentially sample based. Mic array can be either block or sample. So you will need block-to-sample or sample-to-block conversion in your system.

Replies: 13
Views: 231
Last Post By: migueljds ON: Thu Jan 26, 2017 10:56 am
Topic By: Gothmag ON: Wed Jan 25, 2017 6:48 pm
Is there a possibility of getting a similar active/recent posts front page, or quick access to it. It's much easier considering how many different forums and sub forums there are that would need to be sifted through otherwise. However, when looking for an old post that same number of forums is helpful so I don't want to see it go away.