Hi Esmail,
1. To extract the frequencies of details and approximation of a signal that was decomposed by ‘wavedec’ command, you can define the wavelet decomposition parameters and perform the decomposition of the signal into detailed coefficients.
wname = 'db10';
nLevel = 4;
[C, L] = wavedec(a, nLevel, wname);
A4 = appcoef(C, L, wname, 4);
[D1, D2, D3, D4] = detcoef(C, L, [1, 2, 3, 4]);
2.Then you can determine the frequency ranges for each detail and approximation level based on the Nyquist frequency and decomposition level.
for i = 1:nLevel
f_high = Fs / (2^(i-1)); % Upper frequency of the detail
f_low = Fs / (2^i); % Lower frequency of the detail
fprintf('Detail D%d: %.2f Hz to %.2f Hz\n', i, f_low, f_high);
end
f_approx = Fs / (2^nLevel);
fprintf('Approximation A%d: 0 Hz to %.2f Hz\n', nLevel, f_approx);
You can refer to the output below for better understanding:
To know more about ‘wavedec’, ‘appcoef’ or ‘detcoef’ functions in MATLAB, you can refer the following documentations:
- https://www.mathworks.com/help/wavelet/ref/wavedec.html
- https://www.mathworks.com/help/wavelet/ref/appcoef.html
- https://www.mathworks.com/help/wavelet/ref/detcoef.html
Hope this works for you!
