Instantaneous frequency of a time wave by zero-crossing
This function measures the period of a full oscillating cycle.
zc(wave, f, channel = 1, plot = TRUE, interpol = 1, threshold = NULL, xlab = "Time (s)", ylab = "Frequency (kHz)", ylim = c(0, f/2000), warning = TRUE, ...)
wave |
an R object. |
f |
sampling frequency of |
channel |
channel of the R object, by default left channel (1). |
plot |
logical, if |
interpol |
a numeric vector of length 1, interpolation factor. |
threshold |
amplitude threshold for signal detection (in % ). |
xlab |
title of the x axis. |
ylab |
title of the y axis. |
ylim |
the range of y values. |
warning |
a logial to specify if warning message should be
displayed or not when |
... |
other |
If plot is FALSE, zc returns a vector of numeric data with
the instantaneous frequency.
If plot is FALSE, zc returns a two-column matrix, the first column corresponding to time in seconds (x-axis) and the second column corresponding
to the instantaneous frequency of the time wave in kHz (y-axis).
‘NA’s correspond either to pause periods (e. g. detected applying
threshold) or sections of the time wave not crossing the zero line. To remove ‘NA’s with na.omit allows to get only instantaneous frequency values but
discards information about pause sections.
interpol adds points to the time wave by linear interpolation
(through approx). This increases measurement precision but as well
time process. Type argument of plot cannot be set to “l”.
Jerome Sueur sueur@mnhn.fr, Caroline Simonis and Thierry Aubin
Hopp, S. L., Owren, M. J. and Evans, C. S. (Eds) 1998. Animal acoustic communication. Springer, Berlin, Heidelberg.
data(pellucens)
pellu1 <- cutw(pellucens,f=22050,from=0,to=1,plot=FALSE)
# without interpolation
zc(pellu1,f=22050,threshold=5,pch=20)
# with interpolation
zc(pellu1,f=22050,threshold=5,interpol=20,pch=20)
# a way to plot with a line and to filter low frequencies
pellu2 <- zc(pellu1,f=22050,threshold=5,interpol=20,plot=FALSE)
pellu3 <- na.omit(pellu2[,2])
pellu4 <- pellu3[pellu3>3]
plot(x=seq(0,nrow(pellu1)/22050,length.out=length(pellu4)),
y=pellu4,type="l",xlab="Time(s)",ylab="Frequency(kHz)")Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.