seewave (version 1.5.5)

afilter: Amplitude filter

Description

This function deletes all signal which amplitude is below a selected threshold.

Usage

afilter(wave, f, threshold = 5, plot = TRUE,
listen = FALSE, Sample = FALSE,...)

Arguments

wave

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

f

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

threshold

amplitude threshold (in %).

plot

logical, if TRUE plots the new oscillogram (by default TRUE).

listen

if TRUE the new sound is played back.

Sample

a logical, if TRUE and plot is FALSE returns an object of class Sample

...

other oscillo graphical parameters.

Value

• If plot is FALSE, a new wave is returned as a one-column matrix or as a Sample object if Sample is TRUE.

Details

The threshold value is in % relative to the maximal value of wave. Signal inferior to this value is clipped.

See Also

ffilter, oscillo

Examples

data(orni)
op<-par(mfrow=c(2,1))
afilter(orni,f=22050)
title(main = "threshold level = 5")
afilter(orni,f=22050,threshold=0.5,colwave="blue")
title(main = "threshold level = 0.5")
par(op)