R: Teager-Kaiser energy tracking operator

TKEO {seewave}

R Documentation

Teager-Kaiser energy tracking operator

Description

This function computes the Teager-Kaiser energy operator.

Usage

TKEO(wave, f, channel = 1, m = 1, M = 1, plot = TRUE,
xlab = "Time (s)", ylab = "Energy",
type = "l", bty = "l", ...)

Arguments

`wave`	an R object.
`f`	sampling frequency of `wave` (in Hz). Does not need to be specified if embedded in `wave`.
`channel`	channel of the R object, by default left channel (1).
`m`	a numeric vector of length 1 for the exponent parameter. See details.
`M`	a numeric vector of length 1 for the lag parameter. See details.
`plot`	logical, if `TRUE` returns a plot of the TK energy along time (by default `TRUE`).
`xlab`	Label of time x-axis.
`ylab`	Label of energy y-axis.
`type`	if `plot` is `TRUE`, type of plot that should be drawn. See `plot` for details (by default "l" for lines).
`bty`	the type of box to be drawn around the energy plot.
`...`	other `plot` graphical parameters.

Details

The discrete version of the Teager-Kaiser operator is computed according to:

y[n] = x[n]^{2/m} - (x[n-M]*x[n+M])^{1/m}

,
with m the exponent parameter and M the lag parameter which both are usually equal to 1 for a conventional operator.
The Teaser-Kaiser operator can be used to track amplitude modulations (AM) and/or frequency modulations (FM).
See examples.

Value

This function returns a two-column matrix, the first column is time and the second column includes the successive energy values.
m/2 NA values are added at the start and end of the vector.

Author(s)

Jerome Sueur

References

Kvedalen, E. (2003). Signal processing using the Teager Energy Operator and other nonlinear operators. University of Oslo, Department of Informatics, PhD Thesis, x + 100 p.

Examples

op <- par(mfrow=c(2,1))

## sinusoid AM 
s1 <- synth(f=8000, d=0.1, cf=200, am=c(100,10), output="Wave") 
oscillo(s1)
TKEO(s1)
## linear AM decrease
s2 <- synth(f=8000, d=0.1, cf=200, shape="decr", output="Wave") 
oscillo(s2)
TKEO(s2)
## sinusoid FM
s3 <- synth(f=8000, d=0.1, cf=200, fm=c(150,50,0,0,0), output="Wave") 
oscillo(s3)
TKEO(s3)
## linear FM increase
s4 <- synth(f=8000, d=0.1, cf=200, fm=c(0,0,600,0,0), output="Wave") 
oscillo(s4)
TKEO(s4)
## AM and FM
s5 <- synth(f=8000, d=0.1, cf=200, am=c(100,10), fm=c(150,50,0,0,0), output="Wave")
oscillo(s5)
TKEO(s5)
par(op)

[Package seewave version 2.1.6 Index]