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Spectrum After the Time Shift II

Spectrum After the Time Shift II

Explore the impact of a time shift on the signal spectrum.

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In this chapter, we’ll look at the time shift from an IQIQ viewpoint.

A shift in impulse

Let’s assume that a unit impulse signal δ[n]\delta[n] is time-shifted by n0n_0. From the DFT definition, we get

X[k]=n=0N1δ[nn0]ej2πkNn=ej2πkNn0X[k]=\sum_{n=0}^{N-1}\delta[n-n_0]e^{-j2\pi\frac{k}{N}n}=e^{-j2\pi\frac{k}{N}n_0}

because δ[nn0]\delta[n-n_0] is 11 at ...