Harmonic Analysis using wavelet
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Hello everybody, I'm studying harmonic analysis in an electric grid I designed on simulink. I only know one way to do that, which is by FFT (Fast fourier transform) which can be done from the power gui block.
I was wondering if anyone know who can I study harmonic analysis using wavelets in simulink, I can't find any way to do that. (I can't find any tool box for it)
N.B: I'm working on Matlab 2011..
Thanks,,,
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Accepted Answer
Wayne King
on 19 May 2012
DSP System toolbox has dwt block to do the critically-sampled discrete wavelet transform. But no blocks for the nondecimated or CWT.
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Wayne King
on 19 May 2012
It is in the DSP System Toolbox:
http://www.mathworks.com/help/toolbox/dsp/ref/dwt.html
More Answers (2)
NIKOLAY YAKOVENKO
on 9 Feb 2023
Edited: NIKOLAY YAKOVENKO
on 9 Feb 2023
I designed and tested my own CWT (continuous wavelet transform) in Simulink. I do use it successfully.
First, I used these functions to get the wavelets I need, or create the matrix with my own wavelets.
fbMorlet = cwtfilterbank('SignalLength',100,'SamplingFrequency',10,'WaveletParameters',[3,9]);
[psi,freqs]=wavelets(fbMorlet');
Wavelets=transpose(psi);
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1290565/image.png)
Then I used the "Discrete FIR filter" block of DSP toolkit to convolute equal size samples of signal for example 100 samples to the same length wavelets, and then find the index of the frequency that gave the maximum. The "Discrete FIR filter" block of DSP toolkit does not allow the matrix of coefficient, so I had to reverse the inputs, i.e. I put the matrix of wavelets to the signal input of the block, and the signal chunk of 100 samples to the coefficient input. Then I shift the signal by one sample (therefore processing the old 99 samples plus one new, and let the process repeat. This way I search all the input signal for wavelet response sample by sample therefore performing a true CWT in continuos time!
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