qfactor

R2026b

CWT filter bank quality factor

Syntax

qf = qfactor(fb)

Description

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).

Examples

Quality Factor of CWT Filter Bank

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

fb — Continuous wavelet transform filter bank

cwtfilterbank object

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

Output Arguments

qf — Quality factor

positive number

Quality factor, returned as a positive real number.

Data Types: double

Extended Capabilities

Thread-Based Environment

Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.

The qfactor function fully supports thread-based environments. For more information, see Run MATLAB Functions in Thread-Based Environment.

Version History

Introduced in R2018a

R2026b: Use thread-based environments

You can use qfactor in thread-based environments. For more information, see Run MATLAB Functions in Thread-Based Environment.