[hpsdr] Dumb question - HPSDR sound card

[Philip Covington]

On 4/4/07, Terry Fox <tfox at knology.net> wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> This may sound like a divergent path, but...
>
> There is a consistent problem with sound cards used with SoftRocks and other
> simple SDR hardware.  Especially laptops.  I realize the work here on Janus
> & Ozy will create a high-quality converter (I have one set on order), but
> there may be room for a simpler project as well.
>
> 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.
>
> This is an ongoing issue that will not go away for a while.  I realize it
> may "undercut" the Janus/Ozy/Atlas somewhat.  I also realize that there are
> many, many sound cards out there, but all are less than optimum or
> expensive, again especially for laptop use.
>
> The cheap PCM2900 boards got me thinking about this potential project.
> Interfacing a better A/D and D/A to USB in such a way that Windows and Linux
> will find them is all that is required.
>
> Horton comes the closest to this, but it has the QSD and no D/A, I believe.
>
> Spending $400 for a firewire audio card to use a $13 SoftRock Lite with a
> laptop doesn't make sense.  Spending $75 to $100 might.  I believe that a
> project like this would do a lot to simplify and therefore further SDR
> acceptance in the amateur community.
>
> Just a thought.
> Terry

You probably could do something like this (for the target price) with
the TI TLV320AIC23B CODEC:

<http://focus.ti.com/docs/prod/folders/print/tlv320aic23b.html>

and an Altera EPM240 CPLD + Cypress CY7C68013A "FX2" USB microcontroller.

The TI CODEC is 24 bits/96 kHz and around 90 dB SNR.  The nice thing
about this CODEC  is that it does not need much analog supporting
circuitry.

Would you like to take a project like this on as a project leader?

73 Phil N8VB

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