Folks, Got a need for FFT analysis. But it's got to be fast and wide, for example a swath from 70MHz to 90MHz would need to be FFT'd in 500usec or less. Meaning at a rate of more than 2000 FFTs per second. The resolution doesn't have to be great, a 8192-point FFT would be fine. Analog RF conversion could be done as well if it absolutely has to be done. The frequencies and requirements will change but in essence that's one of the jobs at hand. The widest-BW SDR I found is this one, at 4MHz BW: Then there is Ettus but the Windows programming environment for those is IMHO absolutely horrid. I have a Signalhound but somehow those no longer seem to do super high BW fast scans. At least mine won't go past 3frames/second. The best would be if the whole FFT enchilada could happen inside a DSP or FPGA in the radio or analyzer, and only the results are ferried to the PC via a USB link. Is there something better out there? It can cost a kilobuck or more if needed. But ideally not 10 kilobucks. Should run without fancy LabView SW or the like if possible. What we need is basically a waterfall FFT with adjustable rolling speed. -- Regards, Joerg

buy or make? a XC6SLX150T is ~200$ -Lasse

Wideband FFT analyzers? SDR?

Dec 18, 2012 24 Replies

Rate this thread:

Michael A. Terrell 13 years ago

No ready? What were we shipping 11 years ago? The desired microwave band was down converted to 50-90 MHz. Then it digitized everything in that 40 MHz. Software defined the center frequency, IF bandwidth, video or audio bandwidth and type of demodulation, all done in the digital domain. Of course, cheapskates tended to drop dead when they saw that US $80,000 price tag. It was available as a singe channel (DR2000), or a digital dual receiver diversity design (RCB2000). They were designed late in 1998.

Vote

Joerg 13 years ago

Sure. We shipped ultrasound machines in the 90's that digitized a 200MHz swath of spectrum. And yeah, those also cost in that range.

SDR is not ready for a simple reason. I can do the same thing for under a hundred bucks in hardware. BTDT. Now if SDR could do it a lot better or cheaper I'd be all for it. But it can't (yet).

Regards, Joerg http://www.analogconsultants.com/

Vote

Michael A. Terrell 13 years ago

How many million units per year to get that $100 price? What features do you have to do without because it's all analog, or low grade digital?

Vote

Joerg 13 years ago

About 0.005 million :-)

Seriously, I don't do this for the first time.

On this one? None. Goes into a PC and there you do anything you want. With or without SDR. A spectrum is a spectrum is a spectrum. It does not matter how you acquire it.

Regards, Joerg http://www.analogconsultants.com/

Vote

Owen Roberts 13 years ago

Jeorg,

You can do that with optics. A Bragg receiver running into a linear CCD. Very simple to build. I have good relations with a company that makes the wideband cells.

Send me a private email at (decode NATO standard phonetics) oscar sierra romeo @ oscar hotel india oscar dot net.

Steve

Vote

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required