SYMPHASE Change Gabor coefficients to symmetric phase
Usage: c=symphase(c,a);
SYMPHASE(c,a) alters the phase of the Gabor coefficients c so as if
they were obtained from a Gabor transform based on symmetric
time/frequency shifts. The coefficient must have been obtained from a
DGT with parameter a.
Gabor coefficients with symmetric phase correspond to the following
transform:
Consider a signal f of length L and define N=L/a.
The output from c=SYMPHASE(dgt(f,g,a,M),a) is given by
L-1
c(m+1,n+1) = sum f(l+1)*exp(-2*pi*i*m*(l-n*a/2)/M)*conj(g(l-a*n+1)),
l=0
where m=0,...,M-1 and n=0,...,N-1 and l-an is computed modulo L.
SYMPHASE(c,a,'lt',lt) does the same for a non-separable lattice
specified by lt. Please see the help of MATRIX2LATTICETYPE for a
precise description of the parameter lt.
References:
E. Chassande-Mottin, I. Daubechies, F. Auger, and P. Flandrin.
Differential reassignment. Signal Processing Letters, IEEE,
4(10):293--294, 1997.
Url: http://ltfat.github.io/doc/gabor/symphase.html
See also: dgt, phaselock, phaseunlock.
Package: ltfat