lfs {seewave} | R Documentation |
This function linearly shifts all the frequency content of a time wave.
lfs(wave, f, shift, wl = 512, wn = "hanning")
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). |
shift |
positive or negative frequency shift to apply (in Hz).) |
wl |
window length for the analysis (even number of points). |
wn |
window name, see ftwindow (by default "hanning" ). |
A short-term Fourier transform is first applied to the signal
(see spectro
), then the frequency shift is applied and the new
signal is eventually generated using the reverse of the Fourier Transform
(fft
).
There is therefore neither temporal modifications nor
amplitude modifications.
fls
returns a one-column matrix describing the new wave.
Jérôme Sueur jerome.sueur@univ-tours.fr and Thierry Aubin thierry.aubin@ibaic.u-psud.fr
Hopp, S. L., Owren, M. J. and Evans, C. S. (Eds) 1998. Animal acoustic communication. Springer, Berlin, Heidelberg.
data(orni) a<-lfs(orni,f=22050,shift=1000) spectro(a,f=22050,wl=512) # to be compared with the original signal spectro(orni,f=22050,wl=512)