autoc {seewave}R Documentation

Short-term autocorrelation of a time wave

Description

This function returns the fundamental frequency of a harmonic time wave. This is achieved by computing a correlation of the signal with itself after a time delay.

Usage

autoc(wave, f, wl, fmin, threshold = FALSE, plot = TRUE, xlab = "Time (s)", 
ylab = "Frequency (kHz)", ylim = c(0, f/2000), ...)

Arguments

wave data describing a time wave.
f sampling frequency of wave.
wl length of the window for the analysis (even number of points).
fmin the minimum frequency to detect (in Hz).
threshold amplitude threshold for signal detection (in %).
plot logical, if TRUE plots the fundamental frequency against time (by default TRUE).
xlab title of the x-axis.
ylab title of the y-axis.
ylim the range of y values.
... other plot graphical parameters.

Details

Autocorrelation process can be time consuming.

Value

If plot is FALSE, autoc returns a vector of numeric data describing the fundamental frequency in kHz. NA corresponds to pause sections in the signal (see threshold).

Author(s)

Jérôme Sueur jerome.sueur@ibaic.u-psud.fr and Thierry Aubin thierry.aubin@ibaic.u-psud.fr

References

Hopp, S. L., Owren, M. J. and Evans, C. S. (Eds) 1998. Animal acoustic communication. Springer, Berlin, Heidelberg.

Examples

data(sheep)
# fundamental frequency of a bird call (Vanellus vanellus)
autoc(sheep,f=8000,wl=512,t=5,fmin=700)
# overlay on spectrogram
spectro(sheep,f=8000,wl=512,ovlp=75,zp=16,scale=FALSE)
par(new=TRUE)
autoc(sheep,f=8000,wl=512,t=5,fmin=700,type="p",col="black",pch=20,
    xaxs="i",yaxs="i",ann=FALSE,yaxt="n")
legend(0.5,3.6,"Fundamental frequency",pch=20,col="black",bty=0,cex=0.7)

[Package seewave version 1.0 Index]