Minimum Phase

A system is minimum phase when it is causal and stable, and if its inverse is also causal and stable. A filter is minimum phase when all of its poles and zeroes are inside the unit circle.

• The inverse of a minimum phase system is minimum phase.
• For a given amplitude spectrum, there is one and only one minimum phase spectrum.
• The convolution of 2 minimum phase systems is minimum phase.

	% This computes the minimum phase of the wavelet W
	% Needs the signal processing toolbox
	W = flipud(real(ifft(exp(hilbert(real(log(fft(W))))))));