CWT filter bank time-domain wavelets
Filter Bank Time Domain Wavelets
Create a continuous wavelet transform filter bank. Set the sampling frequency to 1000 Hz and the frequency limits to range from 50 Hz to 200 Hz. Plot the frequency response.
fb = cwtfilterbank('SamplingFrequency',1000,'FrequencyLimits',[50 200]); freqz(fb)
Obtain the filter bank time-domain wavelets. Plot the magnitudes of the first and last wavelets contained in the output. The first wavelet corresponds to the wavelet filter with center frequency equal to 200 Hz, and the last wavelet corresponds to the wavelet filter with center frequency equal to 50 Hz.
[psi,t] = wavelets(fb); figure plot(t,abs(psi(1,:))) hold on plot(t,abs(psi(end,:))) legend('Higher CF Wavelet','Lower CF Wavelet') grid on
psi — Time-domain wavelets
Time-domain wavelets, returned as a
Ns-by-N complex-valued matrix,
where Ns is the number of wavelet bandpass frequencies
(equal to the number of scales) and N is the filter bank
SignalLength. The wavelets are ordered in
psi from the highest-frequency passband filter to
the lowest-frequency passband filter.
t — Sampling instants
Sampling instants of the time-domain wavelets, returned as a real-valued
vector of length N, where N is the
SignalLength. The data type of
t is the same as the