Fastest resolution of SDR type radio and spectrograph system?

[Thomas Ashcraft]

What is the fastest resolution you can get with an SDR type of radio and
spectrograph? For example, can you get detail on Jovian S-bursts at
1/100th of a second?

Thomas in New Mexico

[Paul Oxley]

Tom   The answer depends on the sample rate for the SDR. For RASDR that a SARA team is developing, the current max sample rate of 7.68 MS/S would have 130 microseconds between samples. In the future we plan to increase the sample rate when we are able to improve the USB2 transfer capability. If we were to use 40 MS/S (the max for the ADC chip), the period would be 25 microseconds.   To get to the objective of 1/100th of a second, you would need to sample at 2 (Nyquist) * 1/0.01 = 200 Samples per second. Even the sound card based SDRs could acheive this rate.   Paul --- On Tue, 11/6/12, Thomas Ashcraft <ashc...@heliotown.com> wrote:

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[Marcus Leech]

Depends on what FFT resolution you want.

FFTs/second = sample_rate/FFT-length

Even at sound-card rates, (let's say 96000 sps), you could do a 960-point FFT at 100Hz, that's assuming zero overlap.  If you use fancy overlapped FFT schemes you can sacrifice "fidelity" to increase the FFT rate.

-Marcus