Name
Hilbert -- hilbert transform filter (90 degrees phase shift)
Synopsis
hilbert [-n taps]
Function
Apply an odd-tap Hilbert transform filter, phase-shifting the signal by 90 degrees.

This is used in many matrix coding schemes and for analytic signal generation. The process is often written as a multiplication by i (or j), the imaginary unit.

An odd-tap Hilbert transform filter has a bandpass characteristic, attenuating the lowest and highest frequencies. Its band-width can be controlled by the number of filter taps, which can be specified with -n. By default, the number of taps is chosen for a cutoff frequency of about 75 Hz.

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