(^2) Modify the properties of the extracted sinestream input signal input2, as described
in “Modify Estimation Input Signals” on page 5-46.
(^3) Estimate the frequency response sysest2 with the modified input signal using
frestimate.
(^4) Merge the original estimated frequency response sysest and the recomputed
estimated frequency response sysest2:
a Remove data from sysest at the frequencies in sysest2 using fdel.
sysest = fdel(sysest,input2.Frequency)
b Concatenate the original and recomputed responses using fcat.
sys_combined = fcat(sysest2,sysest)
Analyze the recomputed frequency response, as described in “Analyze Estimated
Frequency Response” on page 5-23.
For an example of frequency response estimation with time-varying source blocks, see
“Effects of Time-Varying Source Blocks on Frequency Response Estimation” on page 5-
60
FFT Contains Large Harmonics at Frequencies Other than the
Input Signal Frequency
What Does This Mean?
When the FFT plot shows large amplitudes at frequencies other than the input signal,
your model is operating outside the linear range. This condition can cause problems when
you want to analyze the response of your linear system to small perturbations.
5 Frequency Response Estimation
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