| meanspec {seewave} | R Documentation |
This function returns the mean frequency spectrum (i.e. the mean relative amplitude of the frequency distribution) of a time wave. Results can be expressed either in absolute or dB data.
meanspec(wave, f, wl = 512, wn = "hanning", ovlp = 0, PSD = FALSE, PMF = FALSE, dB = FALSE, from = FALSE, to = FALSE, peaks = FALSE, identify = FALSE, col = "black", cex = 1, colpeaks = "red", cexpeaks = 1, fontpeaks = 1, plot = 1, flab = "Frequency (kHz)", alab = "Amplitude", flim = c(0,f/2000),alim = NULL,...)
wave |
data describing a time wave
or a Sample object created loading a wav file
with loadSample (package Sound). |
f |
sampling frequency of wave (in Hz). |
wl |
length of the window for the analysis (even number of points). |
wn |
window name, see ftwindow (by default "hanning"). |
ovlp |
overlap between two successive analysis windows (in %). |
PSD |
if TRUE return Power Spectra Density,
i. e. the square of the spectra. |
PMF |
if TRUE return Probability Mass Function,
i. e. the probability distribution of frequencie. |
dB |
logical, if TRUE return the spectrum in dB
(by default FALSE). |
from |
start mark where to compute the spectrum (in s). |
to |
end mark where to compute the spectrum (in s). |
peaks |
to return peaks values. |
identify |
to identify frequency values on the plot with the help of a cursor. |
col |
colour of the spectrum. |
cex |
pitch size. |
colpeaks |
colour of peaks value plotted on the spectrum. |
cexpeaks |
character size of peaks value plotted on the spectrum. |
fontpeaks |
font of peaks value plotted on the spectrum. |
plot |
if 1 returns frequency on x-axis, if 2 returns
frequency on y-axis, (by default 1). |
flab |
title of the frequency axis. |
alab |
title of the amplitude axis. |
flim |
range of frequency axis. |
alim |
range of amplitude axis. |
... |
other plot graphical parameters. |
If from and to are FALSE then spec
computes the mean spectrum of the whole signal.
peaks setting corresponds to dimension of embed.
When using identify, press ‘stop’ tools bar button to return values in the console.
If plot is FALSE, meanspec returns a vector of numeric
data corresponding to the computed spectrum.
If peaks is TRUE, spec returns a list with
two elements:
spec |
the spectrum computed |
peaks |
the peaks values (in kHz). |
See examples of spec. This function is based on fft.
Jérôme Sueur jerome.sueur@univ-tours.fr and
Martin Maechler maechler@stat.math.ethz.ch for peaks
data(orni)
# compute the mean spectrum of the whole time wave
meanspec(orni,f=22050,wl=512,type="l")
# compute the mean spectrum of a time wave section (from 0.32 s to 0.39 s)
meanspec(orni,f=22050,wl=512,from=0.32,to=0.39,type="l")
# different window lengths
op<-par(mfrow=c(3,1))
meanspec(orni,f=22050,wl=256,type="l")
title("wl=256")
meanspec(orni,f=22050,wl=1024,type="l")
title("wl=1024")
meanspec(orni,f=22050,wl=4096,type="l")
title("wl=4096")
par(op)
# different overlap values (almost no effects here...)
op<-par(mfrow=c(3,1))
meanspec(orni,f=22050,wl=512,type="l")
title("ovlp=0")
meanspec(orni,f=22050,wl=512,ovlp=50,type="l")
title("ovlp=50")
meanspec(orni,f=22050,wl=512,ovlp=95,type="l")
title("ovlp=95")
par(op)
# use of flim to zoom in
op<-par(mfrow=c(2,1))
meanspec(orni,f=22050,wl=512,type="l")
title("zoom in")
meanspec(orni,f=22050,wl=512,type="l",flim=c(4,6))
par(op)
# comparaison of spectrum and mean spectrum
op<-par(mfrow=c(2,1))
spec(orni,f=22050,type="l")
title("spec()")
meanspec(orni,f=22050,wl=512,type="l")
title("meanspec()")
par(op)