Theorem: For any and any integer ,
The shift theorem says that a delay in the time domain corresponds to a linear phase term in the frequency domain. More specifically, a delay of samples in the time waveform corresponds to the linear phase term multiplying the spectrum, where . (To consider as radians per second instead of radians per sample, just replace by so that the delay is in seconds instead of samples.) Note that spectral magnitude is unaffected by a linear phase term. That is, .