<< ifestar2 Time-Domain Processing loctime >>

Time Frequency Toolbox >> Time Frequency Toolbox > Time-Domain Processing > instfreq

instfreq

Instantaneous frequency estimation.

Calling Sequence

[FNORMHAT,T]=instfreq(X)
[FNORMHAT,T]=instfreq(X,T)
[FNORMHAT,T]=instfreq(X,T,L)
[FNORMHAT,T]=instfreq(X,T,L,TRACE)

Parameters

X :

Analytic signal to be analyzed.

T :

Time instants (default : 2:length(X)-1).

L :

If L=1, computes the (normalized) instantaneous frequency of the signal X defined as angle(X(T+1)*conj(X(T-1)) ; if L>1, computes a Maximum Likelihood estimation of the instantaneous frequency of the deterministic part of the signal blurried in a white gaussian noise. L must be an integer (default : 1).

TRACE :

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

FNORMHAT :

Output (normalized) instantaneous frequency.

T :

Time instants.

Description

instfreq computes the instantaneous frequency of the analytic signal X at time instant(s) T, using the trapezoidal integration rule. The result FNORMHAT lies between 0.0 and 0.5.

Examples

x=fmsin(70,0.05,0.35,25); [instf,t]=instfreq(x); plot(t,instf)
N=64; SNR=10.0; L=4; t=L+1:N-L; x=fmsin(N,0.05,0.35,40);
sig=sigmerge(x,hilbert(rand(N,1,'normal')),SNR);
plotifl(t,[instfreq(sig,t,L),instfreq(x,t)]); xgrid;
title ('theoretical and estimated instantaneous frequencies');

See also

Authors

<< ifestar2 Time-Domain Processing loctime >>