hilbert {seewave}

Hilbert transform and analytic signal

Description

This function returns the analytic signal of a time wave through Hilbert transform.

Usage

hilbert(wave, f, channel = 1, fftw = FALSE)

Arguments

wave

an R object.

f

sampling frequency of wave (in Hz). Does not need to be specified if embedded in wave.

channel

channel of the R object, by default left channel (1).

fftw

if TRUE calls the function FFT of the library fftw for faster computation. See Notes of the function spectro.

Details

The analytic signal is useful to get the amplitude envelope (see argument henv of oscillo and the instantaneous phase or frequency (see ifreq) of a time wave.

Value

hilbert returns the analytic signal as a complex matrix. The imaginary part of this matrix is the Hilbert transform.

Note

To get the Hilbert component only, use Im(Hilbert(wave)).

Author(s)

Jonathan Lees [e-mail]. Implementation of 'fftw' argument by Jean Marchal and Francois Fabianek.

References

Mbu Nyamsi, R. G., Aubin, T. & Bremond, J. C. 1994 On the extraction of some time dependent parameters of an acoustic signal by means of the analytic signal concept. Its application to animal sound study. Bioacoustics, 5: 187-203.

See Also

ifreq

Examples

a<-synth(f=8000, d=1, cf=1000)
aa<-hilbert(a, f=8000)