pure sinusoids ie exponentials form math e j omega n math math omega mathbb r math also written math z n math math z e j omega math discrete time fourier transform dtft math h e j omega mathcal f h n math gives eigenvalues pure sinusoids math h z math math h e j omega math called ' 'system function'' ' 'system response'' ''transfer function'' like one sided laplace transform z transform usually used context one sided signals ie signals zero discrete time fourier transform fourier series may used analyzing periodic signals due convolution
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