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Time Frequency Toolbox >> Time Frequency Toolbox > Linear Time-Frequency Processing > tfrgabor

tfrgabor

Gabor representation of a signal.

Calling Sequence

[TFR,DGR,GAM]=tfrgabor(SIG,N,Q)
[TFR,DGR,GAM]=tfrgabor(SIG,N,Q,H)
[TFR,DGR,GAM]=tfrgabor(SIG,N,Q,H,TRACE)
[TFR,DGR,GAM]=tfrgabor(...,'plot')

Parameters

SIG :

signal to be analyzed (length(SIG)=N1).

N :

number of Gabor coefficients in time (N1 must be a multiple of N) (default : divider(N1)).

Q :

degree of oversampling ; must be a divider of N (default : Q=divider(N)).

H :

synthesis window, which was originally chosen as a Gaussian window by Gabor. Length(H) should be as closed as possible from N, and must be >=N (default : Gauss(N+1)). H must be of unit energy, and CENTERED.

TRACE :

if nonzero, the progression of the algorithm is shown (default : 0).

'plot':

if one input parameter is 'plot', tfrgabor runs tfrqview. and TFR will be plotted

TFR :

Square modulus of the Gabor coefficients.

DGR :

Gabor coefficients (complex values).

GAM :

biorthogonal (dual frame) window associated to H.

Description

tfrgabor computes the Gabor representation of signal X, for a given synthesis window H, on a rectangular grid of size (N,M) in the time-frequency plane. M and N must be such that N1 = M * N / Q where N1=length(X) and Q is an integer corresponding to the degree of oversampling. If Q=1, the time-frequency plane (TFP) is critically sampled, so there is no redundancy in the TFP. If Q>1, the TFP is oversampled, allowing a greater numerical stability of the algorithm.

Examples

sig=fmlin(128);
tfrgabor(sig,64,32,'plot');

Authors

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