FILTERBANKPHASEGRAD Phase gradient of a filterbank representation
Usage: [tgrad,fgrad,s,c] = filterbankphasegrad(f,g,a,L,minlvl);
[tgrad,fgrad,s,c] = filterbankphasegrad(f,g,a,L);
[tgrad,fgrad,s,c] = filterbankphasegrad(f,g,a,minlvl);
[tgrad,fgrad,s,c] = filterbankphasegrad(f,g,a);
[tgrad,fgrad,s] = filterbankphasegrad(...)
[tgrad,fgrad] = filterbankphasegrad(...)
Input parameters:
f : Signal to be analyzed.
g : Cell array of filters
a : Vector of time steps.
L : Signal length (optional).
minlvl: Regularization parameter (optional, required < 1).
Output parameters:
tgrad : Instantaneous frequency relative to original position.
fgrad : The negative of the local group delay.
cs : Filterbank spectrogram.
c : Filterbank coefficients.
[tgrad,fgrad,s,c] = FILTERBANKPHASEGRAD(f,g,a,L) computes the
relative instantaneous frequency tgrad and the negative of the group
delay fgrad of the filterbank spectrogram s obtained from the
signal f and filterbank parameters g and a.
Both tgrad and fgrad are specified relative to the original
coefficient position entirely similar to GABPHASEGRAD.
fgrad is given in samples, while tgrad is given in normalised
frequencies such that the absolute frequencies are in the range of ]-1,1].
This routine uses the equivalence of the filterbank coefficients in
each channel with coefficients obtained from an STFT obtained with a
certain window (possibly different for every channel). As a consequence
of this equivalence, the formulas derived in the reference apply.
References:
F. Auger and P. Flandrin. Improving the readability of time-frequency
and time-scale representations by the reassignment method. IEEE Trans.
Signal Process., 43(5):1068--1089, 1995.
N. Holighaus, Z. Průša, and P. L. Soendergaard. Reassignment and
synchrosqueezing for general time-frequency filter banks, subsampling
and processing. Signal Processing, 125:1--8, 2016. [1]http ]
References
1. http://www.sciencedirect.com/science/article/pii/S0165168416000141
Url: http://ltfat.github.io/doc/filterbank/filterbankphasegrad.html
See also: gabphasegrad.
Package: ltfat