Mexican hat wavelet in time domain.
[H,T]=mexhat() [H,T]=mexhat(NU)
a scalar in [0 0.5] (default : 0.05).
a real row vector of length 2*ceil(1.5/NU)+1: the the mexhat time samples.
a real row vector of length 2*ceil(1.5/NU)+1: the mexican hat time support.
mexhat returns the mexican hat wavelet with central frequency NU (NU is a normalized frequency in Hz).