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Ctfrker

Time frequency representation kernel

Calling Sequence

kernel = Ctfrker(N_Doppler, N_Delay, kernel_type)
kernel = Ctfrker(N_Doppler, N_Delay, kernel_type, optional_parameters)

Parameters

N_doppler :

Number of doppler bins, number of rows in the kernel matrix

N_delay :

Number of delay bins, number of columns in the kernel matrix

kernel :

Computed kernel

kernel_type :

one of the following types:

MTEK :

Multiform tiltable exponential kernel 7 parameters required : [alpha beta gamma r tau_0 nu_0 lambda]

RGK :

Radially gaussian kernel : an odd number of parameters required, the Fourier descriptors of the contour function [c a1 ... ap b1 ... bp]

GMCWK :

Generalized marginals Choi-Williams kernel at least two parameters required : the kernel width and the angles of the branches in [0 pi]. [sigma angle_1 .. angle_2]

WV :

Wigner-Ville kernel : no parameters required

SPECTRO :

Spectrogram kernel The parameters are the window with EVEN length

Description

/ Computes the Cohen's group Time Frequency Representation's (TFR) kernel, in the ambiguity plane.

note: more kernels will be implemented in future versions

Examples

AF = Cambifunb(hilbert(sin(2*%pi*0.25*(1:128))),-63:64,128);
ker = Ctfrker(128,128,'rgk',[1 1 1]);
TFR = Caf2tfr(AF,ker);
grayplot(1:128,linspace(0,0.5,128),TFR');

Bibliography

H. Costa and G.F. Boudreaux-Bartels, Design of Time-Frequency Representations Using a Multiform, Tiltable Exponential Kernel IEEE Trans. on Signal Processing, October 1995, vol. 43, no 10, pp 2283-2301

X.-G. Xia and Y. Owechko and B. H. Soffer and R. M. Matic, Generalized-Marginal Time-Frequency Distributions, TFTS 1996, pp. 509-51

See also

Authors


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