coh {seewave}

Coherence between two time waves

Description

This function returns the frequency coherence between two time waves.

Usage

coh(wave1, wave2, f, channel=c(1,1), plot =TRUE, xlab = "Frequency (kHz)",
ylab = "Coherence", xlim = c(0,f/2000), type = "l",...)

Arguments

wave1

a first R object.

wave2

a second R object.

f

sampling frequency of wave (in Hz). Does not need to be specified if embedded in wave.

channel

channel of the R objects, by default left channel (1) for each object.

plot

logical, if TRUE plots the continuous coherence function (by default TRUE).

xlab

title of the frequency X-axis.

ylab

title of the coherence Y-axis.

xlim

range of frequency X-axis.

type

if plot is TRUE, type of plot that should be drawn. See plot for details (by default "l" for lines).

...

other plot graphical parameters.

Details

Coherence is a frequency domain function computed to show the degree of a relationship between two signals. The value of the coherence function ranges between zero and one, where a value of zero indicates there is no causal relationship between the signals. A value of one indicates the existence of linear frequency response between the two signals. This can be used, for instance, to compare the input and output signals of a system.

Value

When plot is FALSE, this coh returns a two-column matrix, the first column being the frequency axis in kHz (x-axis) and the second column being the coherence (y-axis).

Note

This function is based on spec.pgram.

Author(s)

Jerome Sueur [e-mail] but this function is based on spec.pgram by Martyn Plummer, Adrian Trapletti and B.D. Ripley.

See Also

ccoh, spectro, spec.pgram.

Examples

wave1<-synth(d=1,f=4000,cf=500)
wave2<-synth(d=1,f=4000,cf=800)
coh(wave1,wave2,f=4000)