Can you write a sample code for MATLAB
时间: 2024-03-11 14:47:47 浏览: 20
Sure, here's an example MATLAB code for implementing a 4-band cosine-modulated filter bank (CMFB) using the built-in `firpm` function:
```
% Define the parameters of the filter bank
num_bands = 4; % number of sub-bands
freq_range = [0, 0.2, 0.3, 0.5, 0.6, 1]; % frequency range for each band
band_type = [1 0 1 0]; % band type (1 for passband, 0 for stopband)
% Design the prototype filter
n = 100; % filter length
h = firpm(n-1, freq_range, band_type); % using the Parks-McClellan algorithm
% Modulate the prototype filter to create the filter bank
h_bank = zeros(num_bands, n); % initialize the filter bank
for i = 1:num_bands
freq_center = (freq_range(i*2-1) + freq_range(i*2))/2;
h_bank(i,:) = 2 * h .* cos(pi * (0:n-1) * freq_center);
end
% Apply the filter bank to a test signal
fs = 8000; % sampling rate
t = 0:1/fs:2; % time vector
x = cos(2*pi*1000*t) + cos(2*pi*2000*t); % test signal
y_bank = zeros(num_bands, length(x)); % initialize the output
for i = 1:num_bands
y_bank(i,:) = filter(h_bank(i,:), 1, x);
end
% Plot the original signal and the sub-bands
figure;
subplot(num_bands+1, 1, 1);
plot(t, x);
title('Original Signal');
for i = 1:num_bands
subplot(num_bands+1, 1, i+1);
plot(t, y_bank(i,:));
title(['Sub-Band ', num2str(i)]);
end
```
This code will generate a 4-band CMFB and apply it to a test signal consisting of two sine waves. The resulting output will be 4 sub-bands with different frequency ranges. The output can be visualized using the `subplot` function to plot each sub-band in a separate subplot.