请给我一个matlab振动信号降噪代码

以下是一个基于小波变换的Matlab振动信号降噪代码示例：

% load signal data
load('vibration_signal.mat');
% plot original signal
figure();
plot(vibration_signal);
title('Original Signal');
xlabel('Sample');
ylabel('Amplitude');

% set wavelet and decomposition level
w = 'db6'; % wavelet type
n = 5; % decomposition level

% perform wavelet decomposition
[c, l] = wavedec(vibration_signal, n, w);

% set threshold level
sigma = median(abs(c)) / 0.6745;
threshold = sigma * sqrt(2*log(length(vibration_signal)));

% soft thresholding
c_new = wthresh(c, 's', threshold);

% perform wavelet reconstruction
vibration_signal_denoised = waverec(c_new, l, w);

% plot denoised signal
figure();
plot(vibration_signal_denoised);
title('Denoised Signal');
xlabel('Sample');
ylabel('Amplitude');

该代码通过小波变换将原始振动信号分解成多个尺度的子信号，并通过软阈值法对小波系数进行滤波，最后将滤波后的小波系数进行重构得到降噪后的信号。您可以根据需要调整小波类型、分解级数和阈值等参数以获得更好的降噪效果。