[R] problems with kzft

Markus Häge markus_haege at gmx.de
Fri Oct 2 11:31:49 CEST 2009


Hello there

after I became familiar with R and Design of Experiments, I tried to
make a fourier transform with kzft but failed. I don't understand
kzft.pdf right.

I tried:
t<-1:1000
x<-cos(2*pi*(1/100)*t)
kzft.x1<-kzft(x,200,1,0.005)
x1<-2*Re(kzft.x1$tf[,2]) //Is it "Re" because it's complex? What exactly
do I acess here?

plot(x1,main="sin") /with this I plot the pure sin

I don't understand the fifth argument "n" in kzft().

Now I like to have a picture of the frequencies. Is it the periodogram
with kzp()? I tried something but once more... I don't understand the
examples in kzft.pdf completely:

omega<-seq(0,1,length=481)[2:241]//What for is [2:241]

My idea is to use kzft at different sampling rates of an ADC, or to
improve the measurements of my cheap oscilloscope. Like the FFT-button,
but better and with R.
Is there somewhere a better explanation of kzft() than kzft.pdf?
Or can anybody help me with this package?

thanks

Markus




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