    ## Multiscale TFD

Purpose
Description
Macro Synopsis
Modules
Related Functions
References

### Purpose

Scaled Time-Frequency Distribution using Morlet-Wavelets

### Description

"Multiscale TFD" computes a time-frequency distribution of an input signal x within a given frequency interval as a sequence of short-time spectra of windowed signal segments, the length of each one inversely proportional to the frequency.

This function yields a 2D signal output of the scaled time-frequency distribution displaying time (x-axis) versus frequency (y-axis) with the power or amplitude spectral values given on the z-axis.

"Multiscale TFD" needs the following parameters:

• lower frequency f0 (in reciprocal x-axis units),
• upper frequency f1 (in reciprocal x-axis units),
• fres, which is the output resolution (i.e. number of points) of the frequency axis,
• tres, which is the output resolution (i.e. number of points) of the time axis,
• convolution window size N as number of periods (note that the absolute window size depends on the frequency),
• spectrum type (spectype), which is either
• "Power" (0) or
• "Amplitude" (1)
and
• type of normalisation (normtype), which is either
• "Absolute Power/Amplitude" (0),
• "Spectral Density" (1) or
• "Maximum Norm" (2).
Note: The type of Fast Fourier Transform and the window type applied implicitly can be adjusted in the Basic Options menu under Fourier.

### Macro Synopsis

y = MultiScaleTFD(x,f0,f1,fres,tres,N,spectype,normtype);
signal x, y;
float f0, f1;
int fres, tres, N;
option spectype, normtype;

The result y is a 2D signal.

Spectral

### Related Functions

Momentary ARMA spectrum, STFT.

### References

Akselrod/Keselbrener , Vandenhouten