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Re: [Xylo-SDR] Firewire, DSP and FPGA on one module
Robert,
Thanks for the clarification. I probably jumped into the discussion a
few days late (I've only been reading the posts for a week or so). I
also read SDR as a generic term as opposed to the specific case and now
understand the USB issue.
I will continue to monitor and hopefully will be able to participate and
contribute. There is a great deal I can learn from this forum.
My interests are very much in-line with this discussion but with a
different end goal. I'm kitting the Scotty's Spectrum Analyzer and at
the present time we use a 10.7MHz IF followed by a power detector
(currently the AD8307) but I would like to explore the use of SDR to
replace the power detector (wideband) with a software tunable power
detector. At the present time I don't even need the demodulating
capabilities. The project is very heavily tied to the PC for scanning,
control and display and that is not anything I want or need to do away
with but I could, in my mind, simplify the first LO scanning (now done
with a PLL and DDS for the fine tuning the reference frequency) and use
only the PLL and then scan the IF to pull out the video (vertical trace
of the Spectrum Analyzer) using the SDR techniques (processing done
primarily in the PC sound card or one step beyond with DSP hardware).
Keep up the information and momentium.
73,
Cash Olsen, KD5SSJ
www.zianet.com/erg
http://groups.yahoo.com/group/spectrumanalyzer/
-----Original Message-----
From: xylo-sdr-bounces@lists.ae5k.us
[mailto:xylo-sdr-bounces@lists.ae5k.us] On Behalf Of KD5NWA
Sent: Sunday, December 18, 2005 11:30 AM
To: Xylo-SDR Discussion
Subject: Re: [Xylo-SDR] Firewire, DSP and FPGA on one module
The main thrust right now not necessarily in priority order is to;
1. Eliminate the sound card, with one of superior quality, with
elimination of ground loop noise.
2. Correction of the 200MHz and A/D clocks clock to super accuracy
and stability.
3. Replacing of the parallel port interface in the SDR-1000 which
controls band switching, Autotuner control.
4. Control and audio for improving CW operations.
The ultimate goal being of having one USB cable between the PC and
the SDR 1000 radio, all data and control being done through USB.
Once that is accomplished some in the group are interested in going
further, to at least reduce the load on the CPU by doing some of the
PC's task in the FPGA so slower laptops and PC's will function, if
not outright replace the PC.
Outright replacement of the PC is a very tall task, you will be
replacing all the current software with hardware and with our budgets
all we can afford are limited free tools. I would most likely involve
adding a floating point DSP chip to the mix.
One of the reasons I have pushed for usage of a Cyclone II chip is
the added hardware multipliers that can be used in making a data
crunching unit, most of the FFT and filter code consist of additions,
subtractions, shifting and multiplication.
All these task will be modules of software in the FPGA and can be
added or removed at will for use in other projects.
At 10:20 AM 12/18/2005, you wrote:
>Robert,
>
>I may have read a lot into the project that I wanted to see but I
>thought one of the reasons for the efforts were to replace the desktop
>/ laptop. This thought may apply to the disscussion of the USB 1 or
>2.0, it is a link to the desktop / laptop and we know that can be done,
>but in order to have a SDR free from the big computer we need hardware
>that is fieldable and relatively low power.
>
>Cash
>
>-----Original Message-----
>From: xylo-sdr-bounces@lists.ae5k.us
>[mailto:xylo-sdr-bounces@lists.ae5k.us] On Behalf Of Robert McGwier
>Sent: Sunday, December 18, 2005 4:31 AM
>To: Xylo-SDR Discussion
>Subject: Re: [Xylo-SDR] Firewire, DSP and FPGA on one module
>
>
>Hello Leon!
>
>The 16 bit fixed point DSP chip could be an issue which is dependent on
>how it is used. Dealing with fixed point is an art few can master. I
>did it with the AEA DSP boxes 15 years ago because there was no other
>choice and I am doing it now in FPGA and some smaller spacecraft
>embedded microsystems. I am uncertain about its suitability for
>general
>
>experimentation with the goal of a high performance SDR. If it were a
>32 bit fixed point system, we would be in business. The FPGA seems
>nice enough. The USRP uses Cyclone with 20,000-ish logical elements.
>This has 50K. So that is a win plus it has the 18x18 multipliers. All
>positives. It is my personal opinion that we are better served at this
>time by mostly avoiding the use of DSP chips, especially fixed point
>ones and to rely on our ability to speedily process data on our modern
>desktops. The SDR-1000 DSP core, written by AB2KT and I, recently
>was
>
>hung on the end of an Agilent multi receiver system. It successfully
>prosecuted 92 separate receivers, each sending I/Q at 8000 samples per
>second, simultaneously on a 2.4 GHz Xeon based Dell Server. The
>processor was not sweating at all. It will easily do this up to 48000
>samples per second since we were not consuming 1/6 of the CPU
>resources.
>
>I went to Reno to work with the Gnu Radio folks for a week. Using the
>GnuRadio software elements, plus some blocks I helped write, we
>implemented a 1 Mbps GMSK packet SYSTEM that transfers data over USB
>2.0 (the preferred medium unless you can demonstrate WHY you must have
>firewire) and we did it from scratch in 3 days . You may download that
>software now from GnuRadio. This ran successfully on the N2MJI (USRP
>hardware designer) abacus, a 1.8 GHz celeron laptop. We do need to
>stop underestimating these desktops and to learn how to optimize for
>them because they are so much easier to deal with than DSP chips. DSP
>chips are your last resort and intended primarily for embedded systems
>that must have them. I would limit there use to those places where I
>need a completely standalone device and could afford to hang an
>external
>
>system on the SDR.
>
>The nice thing about using the FX2 and USB 2.0, is that we can and
>should adapt our toy to use the HUGE body of software that GnuRadio has
>produced in addition to those things we can and should add.
>
>73's
>Bob
>N4HY
>
>
>Leon Heller wrote:
>
> >Here is an interesting product with a TI DSP, Spartan 3 FPGA and
> >Firewire:
> >
> >http://www.traquair.com/products/ultracompact/uc1394a-3.html
> >
> >Just add an ADC for a high-performance SDR!
> >
> >Leon
> >--
> >Leon Heller, G1HSM
> >leon.heller@bulldoghome.com http://www.geocities.com/leon_heller
> >---
> >[This E-mail has been scanned for viruses but it is your
> >responsibility
>
> >to maintain up to date anti virus software on the device that you are
> >currently using to read this email. ]
> >
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> >
> >
> >
>
>
>--
>Laziness is the number one inspiration for ingenuity. Guilty as
>charged!
>
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Cecil Bayona
KD5NWA
www.qrpradio.com
"I fail to see why doing the same thing over and over and getting the
same results every time is insanity: I've almost proved it isn't;
only a few more tests now and I'm sure results will differ this time ...
"
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