Hi Markus, Well, the shortest possible pulse has duration 1/sampling rate and can be sent with
0…010…0 Now, that pulse has incredibly little power; and thus, the LO leakage and all negative effects will probably make that unnecessary hard to detect. I really recommend pulse compression: Can't you just generate a random vector of +1/-1, use it as transmit signal (embedded in a few 0s to allow the USRP to ramp up & flush out remaining samples in the DSP chain)? In the receiver, you'd want to correlate against that sequence – and luckily, correlation and convolution are the same but for direction (and complex conjugate, but 1 and -1 are pretty real, so, nothing to conjugate), so just use a FIR filter with the same sequence, just reversed(). You'd get the same resolution (because the cross-correlation would reduce to a single sample, too, as long as your random sequence isn't periodic), but you get n times the power, hence n times the SNR, n being the length of the sequence. Best regards, Marcus PS: Have you played around with gr-radar? https://archive.fosdem.org/2018/schedule/event/radar/ On Fri, 2018-08-10 at 14:57 +0200, Markus Heller wrote: > Dear list, > > I wonder how I could generate one single shortest possible pulse on my > USRP2 with GNURadio. > > Normally all the blocks would always generate an entire sequence, a > continuous signal. > > I want to generate (and analyze) the shortest possible signal. > > Any ideas? > > The background: I want to generate a specific signal and record it's > reflections. Some very basic radar experiments. > > Thanks! > > BR / vy73 > Markus > dl8rds > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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