Use "spectrum analyzer" tool for time-varying signal captured via an SDR device

Dear all

I am intested in plotting the full frequency content of a signal captured by using an SDR device. The sample recording process consists of sequential tuning of the device to adjacent frequencies, fc, and storing a certain fixed amount of samples, N, at each tune, with a bandwidth dictated by the sampling frequency, fs. Sometimes, the acquiring filter has a bandwidth a bit smaller than that given by the sampling frequency, so some degree of overlap is also considered.

What I want to know is whether the spectrum analyzer DSP app can be used to plot the entire spectrum at once. For now, I have not been able to hold one representation when trying to plot the next. I mean, the app "refreshes" the plot every so often, and if I try to add frequency content at higher frequencies, I get the previous erased. I've also tried to consider each set of samples a different "channel" for the app, but I do not like the different color representation of each segment.

Is there any way of using the spectrum analyzer app for this purpose? I know I can do it on my own, calculating FFTs of segments, etc, and I have tried. But I believe I might have done something wrong, since I get strange outputs sometimes, and would like to compare with the plot of the app.

¡Thanks!

Answer 1

[Ben Cunningham]

Hi Toni,

You might find this example useful: https://www.mathworks.com/help/wireless-testbench/ug/capture-from-frequency-band-with-multiple-antennas.html

The example shifts each channel so that they display in the correct position in the spectrum analyser.