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Using ifft() to deconvolve signal and frequency response

Asked by 2one
on 19 Apr 2016
Latest activity Edited by 2one
on 19 Apr 2016
I have a measured time varying signal which is known to have a variable frequency response (I have freq vs. sensitivity data for the measurement device). I want to deconvolve using:
pt = ifft(fft(vt)./Mf)
where vt is the time varying signal and Mf is the frequency response.
I take the magnitude
and divide by the freq. vs. response curve Mf (interpolate to the same frequency range).
However if I set Mf=1 (for all values f=0 to X MHz) I don't get the original signal vt when I do the ifft.
My understanding is I need to perform the division (vt./Mf) on the fft magnitude but then use real/complex fft data for ifft to get the original signal but I'm unsure how to get this to work correctly.


Are you sure you didn't do anything wrong when setting Mf to 1?
x = 0:0.001:0.1-0.001;
y = sin(2*pi*50*x);
Mf = ones(size(y));
plot(x,y,'o'), hold all, plot(x,ifft(fft(y)./Mf),'-')
This seems to work fine with me.
I'm not sure this is exactly the output I require. I need to divide fft(y)./Mf at each point which must have the same frequency value that is if I plotted
plot(f1,fft(y)); hold all; plot(f2,Mf); hold all; plot(f2,fft(y)./Mf)
I first would need to interpolate f1 so it is the same as f2. But I think I need to use abs(fft(y)) rather than fft(y) in the division?

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