mexhat.m

这是伯克里wavelet transforms一书中的例子的代码

function mx = mexhat(a,ts,int)
%mx = mexhat(a,ts,int) creates a Mexican hat wavelet dilated to a factor,
%a. The sampling interval is ts. The samples of the wavelet are returned.
%The samples of the wavelet are taken in the interval, -int to int. 
%Time axis goes from -int to int in steps of ts, the sampling interval
%Note: a MUST NOT be zero.
%This routine is used is by the routine, ctwt.
%
%Author: Ajit S. Bopardikar
%Copyright (c) 1998 by Addison Wesley Longman, Inc.
%

  if(a~=0)
    t=0:ts:int;
    mx=1/sqrt(abs(a)) * (1 - 2*(t/a).^2).*exp(-(t/a).^2);
    l =length(mx);
    mx = [mx(l:-1:2) mx]; %sampled wavelet     
  else
    fprintf('The dilation factor input by you is zero. Cant compute the wavelet samples at this factor\n');
  end %endif