fund: Fundamental frequency track

Description

This function tracks the fundamental frequency through a short-term cepstral transform.

Usage

fund(wave, f, wl = 512, ovlp = 0, fmax, threshold = NULL,
plot = TRUE, xlab = "Time (s)", ylab = "Frequency (kHz)",
ylim = c(0, f/2000), ...)

Arguments

wave

a vector, a matrix (first column), an object of class ts, Sample (left channel), or Wave (left channel).

sampling frequency of wave (in Hz). Does not need to be specified if wave is an object of class ts, Sample, or Wave<

if at is not null, length of the window for the analysis (even number of points, by defaults = 512).

ovlp

overlap between two successive windows (in %).

fmax

the maximum frequency to detect (in Hz).

threshold

amplitude threshold for signal detection (in %).

plot

logical, if TRUE plots the fundamental frequency modulations against time (by default TRUE).

xlab

title of the time axis (s).

ylab

title of the frequency axis (Hz).

ylim

the range of frequency values.

...

other plot graphical parameters.

Value

When plot is FALSE, fund 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).

References

Oppenheim, A.V. and Schafer, R.W. 2004. From frequency to quefrency: a history of the cepstrum. Signal Processing Magazine IEEE, 21: 95-106.

Examples

Run this code

data(sheep)
fund(sheep,f=8000,fmax=300,type="l")
# with 50% overlap between successive sliding windows, time zoom and 
# amplitude filter (threshold)
fund(sheep,f=8000,fmax=300,type="b",ovlp=50,threshold=5,ylim=c(0,1),cex=0.5)
# overlaid on a spectrogram
spectro(sheep,f=8000,ovlp=75,zp=16,scale=FALSE,palette=rev.gray.colors.2)
par(new=TRUE)
fund(sheep,f=8000,fmax=300,type="p",pch=24,ann=FALSE,
  xaxs="i",yaxs="i",col="black",bg="red",threshold=6)

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