[hpsdr] Dumb question - HPSDR sound card

[Terry Fox]

SPDIF on most inexpensive sound cards is one-way - outbound (D/A).  The
wrong way.

I have used SPDIF for a long time, being in broadcast and also recording
concerts with DAT machines.  It works great for some apps, but I doubt it
would fit what I am looking for.  Notebook/laptop support is nonexistant
without another interface to the computer, exactly what I am trying to
avoid.

What rates does SPDIF suppor these days?  192kHz & 24-bit sampling?  I think
so, but most of my hardware is 32/4.1/48k and 16-bit.

I still use SPDIF for DATminidisc, and other pro audio applications, but I
don't think it's what I want for SDR.

----- Original Message ----- 
From: "J.D. Bakker" <jdb at lartmaker.nl>
To: "Terry Fox" <tfox at knology.net>
Cc: "'High Performance Software Defined Radio Discussion List'"
<hpsdr at hpsdr.org>
Sent: Wednesday, April 04, 2007 1:55 PM
Subject: Re: [hpsdr] Dumb question - HPSDR sound card


> >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/
>


 1175717568.0