FPGAs and other misc

Terry Fox tfox at knology.net
Fri Apr 6 12:30:17 CDT 2007

A few years ago, Hal metioned at tacos that more people are using FPGAs to
develop SDR applications.  At that time,t he tools were expensive, and so
were the parts.  I think that has changed some.  The intellectual property
libraries can still cost s alot, but design tools for small and mid-level
FPGAs can be no-cost.

Look at www.fpga4fun.com for some interesting projects.  They have projects
for digital scopes, pc port interfaces, logic analyzers, etc.  There is a
digital scope (RS232 & limited) for under $100.  There are more advanced
disgital scopes with better FPGAs and A/D converters (USB & 100MHz clock)
for about $200 in hardware.  There are other projects of interest as well,
along with a fairly nice forum setup by project.

I remember Andre was talking abotu these digital scopes, and I don't believe
these units are quite waht he is itnerest in, but it is a good entry point.
For the $200, I think it could be an interesting bench tool, plus it allows
us to experiment with high-speed USB interfacing to PCs.  I am VERY tempted.

One of the projects I am interested in is to build a "sound card" like
device that takes the better audio A/D & D/A chips that seem plentiful, and
use an FPGA (or PIC if fast enough) to create a USB interface to the PC.
This is for laptop SoftRock/SDR operation.

I found a board on the internet that interfaces a 48kHz, 16-bit A/D-D/A chip
(PCM-2900) to the PC via USB - for $35.  The audio specs are not that great,
so I am thinking of something a little better.

There are several other similar projects that could be implemented via FPGA.

Anyone out there interested?

I also note that Flex has released info on their new SDR, the Flex 5000.  It
sells for $2,500, and uses a single firewire interface to the PC.  I like
firewire better than USB, but I'm not so sure about inexpensive firewire
interface parts.


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