[hpsdr] Dumb question - HPSDR sound card

[Philip Covington]

On 4/4/07, J.D. Bakker <jdb at lartmaker.nl> wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> >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).

Sounds interesting.  I'll have to do some more reading on SPDIF/AES.

> 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...

The AKM parts are horrible to get in small quantities - I originally
was pushing the TI PCM4202 for a possible ADC for JANUS until the AK
chip outperformed it at 192 kHz in Phil H's testing.  The PCM4202 is
good at 96 and 48 kHz.

> JDB.
> [Plan B is the new TI PCM4222 converter, but that one's so fresh it
> isn't even in sampling yet]

I've been keeping an eye on the PCM4222 also.  Maybe it will be
available by the end of the year?

73 Phil N8VB

 1175711133.0