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Asked by SACHIN DEVASSY
on 30 Sep 2013

Hi, I would like to get bode plot from FFT data. How do I convert the data obtained(complex values) so that it can be used by the 'bode' function in matlab.

Thanking you.

Answer by Arkadiy Turevskiy
on 30 Sep 2013

You need to create an frd object.

here is example code from doc page.

% generate a frequency vector and response data freq = logspace(1,2); resp = .05*(freq).*exp(i*2*freq); % Create a FRD model sys = frd(resp,freq);

Now simply do

bode(sys)

SACHIN DEVASSY
on 1 Oct 2013

Thanks Arkadiy for the reply. However, I am unable to understand how to make frd data from fft data. I got lets say ,following data points after doing fft [2+2j,1-3j,4, 5+4j]. How do i convert this into frd. Thanking you.

Arkadiy Turevskiy
on 1 Oct 2013

resp=[2+2j,1-3j,4, 5+4j]; freq= % enter the frequency values at which the corresponding fft % values are obtained sys=frd*resp,freq);

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