平移变换平移法(cycle_spinning)消除gibbs效应.txt

利用平移变换平移法消除去噪过程中产生的gibbs效应

平移变换平移法(cycle_spinning)消除gibbs效应 
 
clear;
clc;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%  1.原始信号
f=50;    % 信号频率
fs=800;  % 采样频率
N=128;   % 采样点 
%  信号赋值
n=1:N;
y=sin(2*pi*f*n/fs);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%  2.噪声
noise=0.4*rand(1,128);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%  3.染噪信号
y_noise=y+noise;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%  4.硬消噪采用cycle_spinning技术
%  累加量
z5=zeros(1,N);
%  平移变换频移法
for i=1:N;
    z=circshift(y_noise.',i-1).';  %  源信号右平移
    [z1,z2]=lwt(z,'db3');    %  小波正变换
    z2=zeros(1,N/2);         %  高频分量全部为零（主要噪声，硬消噪）
    z3=ilwt(z1,z2,'db3');    %  小波反变换  
    z4=circshift(z3.',-(i-1)).';  %  变换后信号左平移  
    z5=z5+z4/N;  %  平均  
end;
    
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%  5.显示
error=norm(y-z5)/norm(y);  % 相对误差
figure(1);
subplot(2,1,1)
plot(y,'r');
legend('源信号');
subplot(2,1,2);
plot(y_noise);
legend('染噪信号');

figure(2);
subplot(2,1,1)
plot(y,'r');
legend('源信号');
title(error);
subplot(2,1,2);
plot(z5);
legend('消噪后信号');