www.gusucode.com > wavelet 源码程序 matlab案例代码 > wavelet/Level3ApproxCoefficientsExample.m
%% Level 3 Approximation Coefficients % This example shows how to extract the level 3 approximation coefficients. %% % Load the signal consisting of electricity usage data. % Copyright 2015 The MathWorks, Inc. load leleccum; sig = leleccum(1:3920); %% % Obtain the DWT down to level 5 with the |'sym4'| wavelet. [C,L] = wavedec(sig,5,'sym4'); %% % Extract the level-3 approximation coefficients. Plot the original signal % and the approximation coefficients. Lev = 3; a3 = appcoef(C,L,'sym4',Lev); subplot(2,1,1) plot(sig); title('Original Signal'); subplot(2,1,2) plot(a3); title('Level-3 Approximation Coefficients'); %% % You can substitute any value from 1 to 5 for |Lev| to obtain the % approximation coefficients for the corresponding level.