Hello everybody,

I have been trying to plot the FFT of a time series signal which is the output of a
time-invariant linear system as well as the ETFE of the same system. Both plots turn out to be
very noisy. I have tried “windowing” to smooth the ETFE plots but it does not help that
much. Is there any well-established method for fitting a smooth plot to a noisy ETFE or finding
an envelope for the FFT plots already coded up in MATLAB?

thanks,

Roshanak
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