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Paul C
Posts:
5
Registered:
2/27/07


System Identification Toolbox "Frequency Function"
Posted:
Apr 19, 2014 3:57 PM


When using the System Identification interactive tool (>> ident), why does the Frequency Function Data window (the transfer function estimate) only start at higher frequencies?
I made a simple example of two phase shifted 10Hz sinusoid waves. The Periodogram (FFT squared) shows data from 1 to 200 Hz, but the Frequency Function Data only starts at 10 Hz. Since the Frequency Function is just the ratio of the FFTs, it should go down to 1 Hz.



