Re: [Xylo-SDR] Clocks for USB FX2, TI PCM4202, etc.

[pvharman@arach.net.au]

Hi Lyle,

I think the advantage of 24.576MHz is that during early testing and 
integration you can feed the audio from the A/D into a standard soundcard in 
the PC. Once that is working, and we have our own D/A's, then I agree that we 
don't need to use standard soundcard sampling rates. 

Phil...

Quoting Lyle Johnson <kk7p@wavecable.com>:

> Hello Don!
> 
> There maybe an even simpler solution.
> 
> The 24.576 MHz requirement is only true if it is important that the 
> sampling be done at precisely 192 kHz.  If you clock it at 24 MHz, 
> you'll get 187,500 Hz sampling (or 93,750 or 46,875).  I suspect there 
> is no particular requirement for sampling at exactly the standard audio 
> rates for most of the applications that have been mentioned here.
> 
> Of course, part of the beauty of all this is that you can easily 
> implement in the FPGA the digital logic portion of the frequency scheme 
> you described.  It would only consume a tiny fraction of the FPGA 
> resources.  And also include the reflock...
> 
> Lyle KK7P
> 
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