seewave (version 1.6.4)

autoc: 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 = 512, fmin, fmax, threshold = NULL, plot = TRUE,
xlab = "Time (s)", ylab = "Frequency (kHz)", ylim = c(0, f/2000), pb =
FALSE, ...)

Value

• When plot is FALSE, autoc returns a two-column matrix, the first column corresponding to time in seconds (x-axis) and the second column corresponding to to fundamental frequency in kHz (y-axis). NA corresponds to pause sections in wave (see threshold).

Details

'fmin' and 'fmax' can help by reducing computing time but can also produce less accurate results.

References

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

See Also

ceps, acf

Examples

data(sheep)
# fundamental frequency of a sheep
res <- autoc(sheep, f=8000, threshold=5, fmin=100, fmax=700, plot=FALSE)
spectro(sheep, f=8000, ovlp=75, scale=FALSE)
points(res, pch=20)
legend(0.5, 3.6, "Fundamental frequency", pch=20, bty=0, cex=0.7)