Recall from Problem 4.32 that an LTI system cannot produce frequencies at its output that are different from those applied in its input. Thus if a system creates “new” frequencies, it must be nonlinear and/or time varying and determine the output spectra when the input spectrum is 

(a) y (n) = x(2n)

(b) y (n) = x²(n)

(c) y (n) = (cos πn) x (n) 

Transcribed Image Text:

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