Robert,
Although I've got about 20 years experience doing boards, FPGAs and
ASICs for digital communications, my current activity in SDR is mostly
limited to lurking on various lists & IRC channels. I've got a Beagle,
various FPGA boards and I even have an RF front end board, but I haven't
had time to integrate them all together.
I believe that I've seen some of the activity you've been involved in on
the Beagleboard IRC channel (I'm 'emeb' over there) - lots of progress
being made on that front. I can't say that I'm aware of any other good
sources of info on the web for SDR, besides those relating to GnuRadio
which I'm sure you're aware of.
I'd agree that USRP/USRP2, while excellent platforms are beyond the
reach of many hobbyists - the price is difficult to justify for many
folks who have only vague notions of what they want to do. That said,
there are ways to integrate lower-cost hardware with GnuRadio, it just
requires a bit more detailed work than the pre-packaged stuff you get
when paying more.
Eric
Rob wrote:
Eric,
Excellent "point" about "floating"! B^) What are you doing with SDR in
your specific arena? Sounds like you know a thing or two and I'm
relatively new to the DSP and SDR world. I'd really like to know how to
get in on this conversation and have been to opensdr.com
<http://email.secureserver.net/addressBookQuickAdd.php?contact=beagle-sdr%40opensdr.com>
but see nothing relating to this list serve. I'm sure I signed up for
something as I was putting together my sources for my project but can't
seem to find a way to backtrack to what the URL was. So point me in the
right direction if you will, tnx.
BTW, my project is to assemble a <SDR (Soft Rock 6.3 RXTX)
>+<Beagleboard>+<Touchscreen> to create a stand alone ham station
featuring popular off-the-shelf, Open Source SDR software like FLDigi,
SDR-Shell, GnuRadio etc. This would have approx. a 1" x 4" x 6"
footprint and run on a 12vdc battery / solar source.
As of this Tuesday Koen Kooi, got FLDigi, Hamlib, SDR-Shell and Jackd
all running in Angstrom on the Beagelboard. and had previously mentored
me on how to use the OE toolchain, bitbake, etc. and get all that on my
SD card! This means that I can use any of the Soft Rock series (v6.3 =
$58 +/-) or even Dave Benson' sSmall wonder Labs PSK20 / 80 transceivers
($55+/-) for receiving and transmitting and it will DECODE <----(
important distinction when talking about SDR applications!!) ------->
and ENCODE digital radio modes. Add a 10W amp and you have a serious
piece of communications gear! So I would guess that in am about 85%
complete, have everything running but the touchscreen and am in the
process of putting a case around the whole thing. I should have my Rhino
drawings for that done this weekend.
I don't know much about the USRP but it looks like a more serious, and
expensive, scientific platform than something that hams might be able to
manage both knowledge-wise as well as financially. So I'm glad that my
project perhaps opens the door to a middle ground, if you will. I will
keep the wiki/list/blog/whatever apprised of the project's status. Look
forward to chatting with you all. We actually may have chatted already
in Beagle chat? I'm bobkatzz! < - - -outted! B^)
Regards,
Robert Bruce Thomas, B.I.D.
Industrial Designer
Technology Integration Specialist
Richmond, Virginia, 23229
804.833.4470
http://www.klikhome.com
-------- Original Message --------
Subject: Re: Slides from wirel...@vt symposium
From: Eric Brombaugh <[email protected]>
Date: Fri, June 12, 2009 12:03 pm
To: [email protected]
Mark Porter wrote:
> The only unfortunate limitation on the Cyclone is the absence of
> floating point, which might be a (big) issue sometimes.
I'm curious if there is any FPGA which has native floating point
support. My understanding was that the nature of an FPGA was to provide
low level logic resources - if you need floating point, build it out of
the gates/registers/etc that are provided.
That said, I've found very few cases where the dynamic range of full
floating point is required in RF/communications front-end processing.
I've seen block floating point used in hardware FFTs in the past, but
seldom in other applications. Most demods are dealing with so much
noise
and distortion to begin with that floating point would be, well,
pointless.
Eric
