Wavelets: how to pass to the cwtfilterbank() wavelets included in the "waveletfamilies" list?

I can not find a clear explanation about how to use wavelets included in the waveletfamilies list.

I tried to pass the parameter of the wavelet within the cwtfilterbank, but it doesn't work.

The following code line

fb = cwtfilterbank('SignalLength',length(Power),'SamplingFrequency',Fs,Wavelet="haar");

as expected, returns the error

Expected Wavelet to match one of these values:

'morse', 'amor', 'bump'

The input, 'haar', did not match any of the valid values.

As expected, the line:

fb = cwtfilterbank('SignalLength',length(Power),'SamplingFrequency',Fs,Wavelet="amor");

works without problems.

Answer 1

[Suvansh Arora]

You cannot apply ‘Haar’ wavelet using ‘cwtfilterbank’ command. For complete list of wavelet families and how to visualise them, please follow the documentation mentioned below:

Introduction to Wavelet Families - MATLAB & Simulink

To visualize ‘Haar’ wavelet, we do have several built-in functions to help you perform continuous wavelet transforms and analyse the time series data. Please refer to the documentation pages below for featured examples:

• Time Frequency Analysis of modulated signals
• ‘Haar’ transforms for time series data and images

We also have two functions that can perform specifically a ‘Haar’ 1-D wavelet transform ("haart"), as well as continuous 1-D wavelet transforms ("cwt"). Please refer to the documentation pages below for more information regarding these functions as well as examples of how to use:

• ‘Haart’ Documentation
• ‘cwt’ documentation

You may try 'cwt' command with "Haar" wavelets, but it does not use FFT algorithm, and you will not be able to see the frequency analysis results.

This may also incur some loss of time resolution. If it is a matter of not wanting to suffer this loss, then you may want to try the 'modwt' function. For more information regarding the "modwt" function, please refer to the documentation page below:

https://www.mathworks.com/help/wavelet/ref/modwt.html

I hope the above information helps you.