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tfrbj

Born-Jordan time-frequency distribution.

Calling Sequence

[TFR,T,F] = tfrbj(X)
[TFR,T,F] = tfrbj(X, T)
[TFR,T,F] = tfrbj(X, T, N)
[TFR,T,F] = tfrbj(X, T, N, G)
[TFR,T,F] = tfrbj(X, T, N, G, H)
[TFR,T,F] = tfrbj(X, T, N, G, H, TRACE)
[TFR,T,F] = tfrbj(...,'plot')

Parameters

X :

A Nx elements vector (auto-BJ) or a Nx by 2 array signal (cross-BJ).

T:

a real Nt vector with elements in [1 Nx] : time instant(s) (default: 1:NX).

N:

a positive integer: the number of frequency bins (default:NX). For faster computation N should be a power of 2.

G:

a real vector with odd length: the time smoothing window, (default :Hamming(N/10)).

It will be normalized such as the middle point equals 1 to preserve signal energy .

H :

real vector with odd length: the frequency smoothing window,(default: Hamming(N/4)).

It will be normalized such as the middle point equals 1 to preserve signal energy.

TRACE :

A boolean (or a real scalar) if true (or nonzero),the progression of the algorithm is shown (default : %f).

'plot':

if one input parameter is 'plot', tfrqview is called and the time-frequency representation will be plotted.

TFR :

A real N by Nt array: the time-frequency representation.

F :

A N vector of normalized frequencies.

Description

tfrbj computes the Born-Jordan distribution of a discrete-time signal X, or the cross Born-Jordan representation between two signals.

Examples

Interactive use

N = 128;
sig = fmlin(N,0.05,0.3) + fmlin(N,0.15,0.4);
g = window("kr",9,3*%pi);
h = window("kr",27,3*%pi);
t = 1:N; 
tfrbj(sig,t,N,g',h',1,'plot');

Non interactive use

N = 128;
sig = fmlin(N,0.05,0.3) + fmlin(N,0.15,0.4);
g = window("kr",9,3*%pi);
h = window("kr",27,3*%pi);
t = 1:N; 
[TFR,T,F] = tfrbj(sig,t,N,g,h);
clf; gcf().color_map = jetcolormap(128);
grayplot(T,F,TFR');

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<< Bilinear Time-Frequency Processing in the Cohen's Class Bilinear Time-Frequency Processing in the Cohen's Class tfrbud >>