par(mfrow=c(2,2))
f <- 8000
a <- noisew(f=f,d=1)
spectro(a,f=f,scale=FALSE)
title(main="input noise")
b <- fir(a,f,to=1500)
spectro(b,f=f,scale=FALSE)
title(main="1.5 kHz bandpass")
c <- fir(a,f=8000,from=1000,to=2000,bandpass=FALSE)
spectro(c,f=f,scale=FALSE)
title(main="1-2 kHz bandstop")
myfilter1 <- rep(c(rep(0,32),rep(1,32)),4)
d<-fir(a,f=f,custom=myfilter1)
spectro(d, f=f, scale=FALSE)
title(main="custom filter")