www.gusucode.com > wavelet 源码程序 matlab案例代码 > wavelet/TimeAlignedMODWPTExample.m

    %% Time-Aligned MODWPT
% Obtain the time-aligned MODWPT of two intermittent sine waves in noise. 
% The sine wave frequencies are 150 Hz and 200 Hz. The data is sampled at 
% 1000 Hz.  
dt = 0.001;     
t = 0:dt:1-dt;     
x = cos(2*pi*150*t).*(t>=0.2 & t<0.4)+ sin(2*pi*200*t).*(t>0.6 & t<0.9);     
y = x+0.05*randn(size(t));
[wpta,~,Falign] = modwpt(x,'TimeAlign',true);
[wptn,~,Fnon] = modwpt(x);
%%
% Compare the nonaligned and time-aligned time-frequency plots. 
subplot(2,1,1);
contour(t,Fnon.*(1/dt),abs(wptn).^2); 
grid on;     
ylabel('Hz');     
title('Time-Frequency Plot (Nonaligned)');
subplot(2,1,2)     
contour(t,Falign.*(1/dt),abs(wpta).^2); 
grid on;     
xlabel('Time'); 
ylabel('Hz');     
title('Time-Frequency Plot (Aligned)');