Name

TimeFrequencyTool — Tool based on time frequency methods

Calling Sequence

TimeFrequencyTool(signal,freq_sampling,options)

Parameters

signal

a real vector, the signal to be analyzed.

freq_sampling

a positive scalar, the sampling frequency of the signal.

options

A struct with possible fields:

  • <term>freq_step</term>, a scalar, the frequency resolution in Hz.
  • <term>fwl</term>, a positive scalar the frequency window length
  • <term>twl</term>, a positive scalar the time window length
  • <term>method</term>, a character string with possible values: "sp" (spectrogram), "spwv" (smoothed pseudo Wigner-Ville), ""zam" (Zao-Atlas-Marks time-frequency distribution), "bj" (sBorn-Jordan time-frequency distribution),
  • <term>draw_type</term>, a character string with possible values "pseudocolor" (2D display done by grayplot ), "3d" (3D display done by plot3d1)
  • <term>cmap</term>, a character string with possible values "jet" (jetcolormap used) or "gray" (reverted graycolormap used).

Description

This tool can be used to explore the spectrum and the frequency evolution of a signal using various time frequency methods and various visualization methods.

Examples

datafile   = path=cardiovascularpath()+"demos/DATA/apnee_spont";
d=read(datafile,-1,7);
freq_sampling=4;
RR=d(:,1);
Vt=d(:,5);

f1=scf(100001);clf;f1.figure_position=[0 0];f1.figure_size=[524 514];
f1.figure_name="TimeFrequency RR apnea";
TimeFrequencyTool(RR,freq_sampling) 

f2=scf(100002);clf;f2.figure_position=[450 0];f2.figure_size=[524 514];
f2.figure_name="TimeFrequency Vt apnea";
TimeFrequencyTool(Vt,freq_sampling) 
    

See Also

Ctfrbj, Ctfrzam, Ctfrspwv, Ctfrsp, grayplot, plot3d1

Authors

Serge Steer, INRIA

Used Functions

Mainly based on the tome frequency toolbox stftb