I'm trying to use either one of these blocks (FFT/FFT MAgnitude/periodogram) to get the power spectral density of a signal. When I export the output of any of these blocks to Matlab Workspace, I get a n*n matrix and when identical rows. Plotting each column gives a periodic thing which doesn't make sense since the signal is a periodic which three frequency components. I need to find a way to export the data from FFT/PSD block to workspace and have both frequency and corresponding magnitude.
The other issue is that I need to perform this on separate segment of the signal. Meaning imagine tif the signal length is 30 seconds, I want to perform a PSD/FFT on each 5 second segment of the signal. To conclude, my problems are two: first getting the PSD/FFT and then be available to chop the running signal on real time and get the FFT/PSD of each segment.