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CWT filter bank quality factor



qf = qfactor(fb) returns the quality factor for the wavelet bandpass filters in fb. The quality factor is the ratio of the 3-dB bandwidth to the center frequency, where the center frequency is the geometric mean of the bandwidth frequencies. The larger the quality factor, the more frequency localized the wavelet. For reference, a half-band filter has a quality factor of sqrt(2).


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Create a CWT filter bank using the default analytic Morse (3,60) wavelet.

fb = cwtfilterbank;

Compute the quality factor of the filter bank.

qf = qfactor(fb)
qf = 4.6296

Create a CWT filter bank using the analytic Morse (3,10) wavelet. Compute the quality factor of the filter bank. The analytic Morse (3,10) wavelet is not localized in frequency as well as the Morse (3,60) wavelet. Confirm that the quality factor of the second filter bank is smaller than the first filter bank.

fb2 = cwtfilterbank('Timebandwidth',10);
qf2 = qfactor(fb2)
qf2 = 1.8445

Input Arguments

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Continuous wavelet transform (CWT) filter bank, specified as a cwtfilterbank object.

Output Arguments

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Quality factor, returned as a positive real number.

Data Types: double

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced in R2018a