seewave (version 1.4.5)

synth: Synthesis of time wave

Description

This functions synthesize pure tone sound with amplitude modulation (am) and/or frequency modulation (fm).

Usage

synth(f, d, cf, a = 1, shape = NULL, p = 0, am = c(0, 0), fm = c(0, 0, 0),
plot = FALSE, listen = FALSE, Sample = FALSE,...)

Arguments

f

sampling frequency (in Hz).

d

duration (in s).

cf

carrier frequency (in Hz).

a

amplitude (linear scale, relative when adding different waves).

shape

modification of the whole amplitude shape of the wave. See details).

p

phase (in radians).

am

a vector of length 2 describing amplitude modulation parameters, see details.

fm

a vector of length 3 describing frequency modulation parameters, see details.

plot

if TRUE returns the spectrogram of the synthezised sound (by default FALSE).

listen

if TRUE the new sound is played back using play from the package sound (by default FALSE).

Sample

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

...

other spectro 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

shape allows to modify the whole amplitude shape of the wave. There are four options to be given as as character string: (i) "incr" : linear increase (ii) "decr" : linear decrease (iii) "sine" : sinusoid-like shape (iv) "tria" : triangular shape am is a vector of length 2 including: (1) the amplitude modulation depth (in %), (2) the frequency of the amplitude modulation. fm is a vector of length 3 including: (1) the maximum excursion of a sinusoidal frequency modulation (in Hz), (2) the frequency of a sinusoidal frequency modulation, (3) the maximum excursion of a linear frequency modulation (in Hz).

References

Hartmann, W. M. 1998 Signals, sound and sensation. New York: Springer.

See Also

noise, pulse

Examples

# pure tone
synth(f=22050,d=1,cf=4000,plot=TRUE)
# pure tone with sinusoid-like overall shape
synth(f=22050,d=1,cf=4000,shape="sine",plot=TRUE,osc=TRUE)
# pure tones with am
synth(f=22050,d=1,cf=4000,am=c(50,10),plot=TRUE,osc=TRUE)
# pure tone with +2000 Hz linear fm 
synth(f=22050,d=1,cf=4000,fm=c(0,0,2000),plot=TRUE)
# pure tone with sinusoidal fm
# (maximum excursion of 1000 Hz, frequency of 10 Hz)
synth(f=22050,d=1,cf=4000,fm=c(1000,10,0),plot=TRUE,wl=256,ovlp=75)
# pure tone with sinusoidal am
# (maximum excursion of 1000 Hz, frequency of 10 Hz)
# and linear fm (maximum excurion of 1000 Hz
synth(f=22050,d=1,cf=4000,fm=c(1000,10,1000),plot=TRUE,wl=256,ovlp=75)
# the same with am
synth(f=22050,d=1,cf=4000,am=c(50,10),
    fm=c(1000,10,1000),plot=TRUE,wl=256,ovlp=75,osc=TRUE)
# the same with am and a triangular overall shape 
synth(f=22050,d=1,cf=4000,shape="tria",am=c(50,10),
    fm=c(1000,10,1000),plot=TRUE,wl=256,ovlp=75,osc=TRUE)   
# more complex sound
F1<-synth(f=22050,cf=2000,d=1,fm=c(500,5,0),plot=FALSE)
F2<-synth(f=22050,a=0.8,cf=4000,d=1,fm=c(500,5,0))
F3<-synth(f=22050,a=0.6,cf=6000,d=1,fm=c(500,5,0))
F4<-synth(f=22050,a=0.4,cf=8000,d=1,fm=c(500,5,0))
final1<-F1+F2+F3+F4
spectro(final1,f=22050,wl=512,ovlp=75,scale=FALSE)
# insert 0.25 s silence
final1.1<-as.matrix(final1[1:(nrow(final1)/2),])
final1.2<-as.matrix(rep(0,0.25*22050))
final1.3<-as.matrix(final1[(nrow(final1)/2):nrow(final1),])
final2<-rbind(final1.1,final1.2,final1.3)
spectro(final2,f=22050,plot=TRUE,wl=512,ovlp=75,scale=FALSE)