Date: Oct 7, 2013 3:31 PM
Author: izik
Subject: S parameters response

Hi all, 

I am testing the influence of band pass filter on LFM signal.
What I do is the following:

1. Generate ideal LFM signal with chirp function.
2. read S parameters file of real life filter.
3. fft to lfm signal
4. multiply fft of LFM with S parameters (in Freq domain)
5. ifft to filtered LFM
6. compare filtered lfm vs ideal lfm in time domain.

I have the following problem:
after ifft of filtered LFM I see the sample freq modulated inside the LFM. so I applied fir1, but still I get some weird results. The ifft result is complex, and I know it's not suppose to be, since the ifft of the ideal signal is not.

I hope that my question is clear; the code is quite long, but if needed I will post it.
Any ideas?

Many thanks