Harmonic Analysis using wavelet

Question

Ayman Esmat 2012-5-19

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https://ww2.mathworks.cn/matlabcentral/answers/38849-harmonic-analysis-using-wavelet

评论： Ahmad Aldiab 2024-4-17

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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Answer 1

Wayne King 2012-5-19

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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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Ayman Esmat 2012-5-19

where can I find that?!

Thanks again,

Wayne King 2012-5-19

It is in the DSP System Toolbox:

http://www.mathworks.com/help/toolbox/dsp/ref/dwt.html

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Answer 2

Madhura 2013-9-24

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https://ww2.mathworks.cn/matlabcentral/answers/38849-harmonic-analysis-using-wavelet#answer_97648

wavemenu is a command to find wavelet toolbax

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Answer 3

NIKOLAY YAKOVENKO 2023-2-9

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编辑：NIKOLAY YAKOVENKO 2023-2-9

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);

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!