MATLAB: Is WAVEDEC returning an error indicating that a wavelet is invalid in the Wavelet Toolbox 2.2 (R13SP1)

dbdb1dwtinvalidmexhwavedecwaveletWavelet Toolboxwname

According to the documentation for the WAVEDEC function, I can use a specific wavelet with the syntax:
[C,L] = wavedec(X,N,'wname')
However, when I use certain wavelets, such as the MEXH wavelet, I receive an error:
 ***********************************************
 ERROR ... 
 -----------------------------------------------
wfilters ---> The wavelet mexh is not valid!
 ***********************************************
 ??? Error using ==> wfilters
 *
 Error in ==> D:\MATLAB6p5p1\toolbox\wavelet\wavelet\wavedec.m
 On line 35  ==>     [Lo_D,Hi_D] = wfilters(varargin{1},'d');

Best Answer

The WAVEDEC function uses the DWT function, which can only use certain wavelets. It is theoretically impossible to use certain wavelets with the discrete wavelet function DWT.
We have verified that documentation onthe WAVEDEC function is missing from the Wavelet Toolbox.
The documentation should read "Only wavelets that support Discrete Analysis (DWT) can be used with WAVEDEC."
You can see which wavelets are supported by DWT and WAVEDEC using the WAVEINFO function.
waveinfo('db')
waveinfo('mexh')
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