[hpsdr] Dumb question - HPSDR sound card

[J.D. Bakker]

>How difficult would it be to take the A/D & D/A and interface them to an
>FPGA or other USB/firewire interface, all on a single, low-cost board?  For
>those not interested in spending over $350 for Atlas, Janus, Ozy (or
>expensive commercial USB/firewire solutions), this one-board solution would
>be attractive.  I think it would need to cost less than $100.

USB audio is non-trivial for rates other than 16bit/44k1. I would 
personally suggest using a SPDIF/AES digital audio interface, thus 
allowing an optical interface to a budget sound card. The major 
advantage is that this offers direct software compatibility with 
existing SDR applications, while the ADC/DAC can be better than 
conventional sound cards (and closer to the mast, if desired).

Single chip solutions are available to connect ADC/DAC chips directly 
to electrical/optical S/PDIF links. I would be willing to do an open 
design based on the AK converter used in Janus, with audio 
in->electrical/optical out. My main stumbling block is that I have no 
source for the AK chips in proto quantities. If only someone could 
sell me some / point me to a distributor who's willing to sell a 
dozen or so to Europe...

JDB.
[Plan B is the new TI PCM4222 converter, but that one's so fresh it 
isn't even in sampling yet]
-- 
LART. 250 MIPS under one Watt. Free hardware design files.
http://www.lartmaker.nl/

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