[PLUG] Digital Signal Processing?

[Russell Senior]

>>>>> "M" == M Edward (Ed) Borasky <znmeb at cesmail.net> writes:

M> You're describing what you're trying to accomplish in rather
M> low-level DSP detail. There are some very "user friendly" DSP
M> packages out there.  

I don't need graphics, I need a number and I need to do it in "batch
mode" over a large number of wave captures, so I want to do it in C.
I am already using FFTW.  I mostly just need to understand how to
apply the windowing (e.g. Hamming and Flat-top, which I think I am
*starting* to get a handle on).  The thing I seem to be missing right
now is what scaling factors need to be applied to the FFT results to
recover amplitude accurately.  If I inject a sine-wave of known
amplitude, I am not getting that back out of the FFT, when that is
precisely what I need to do.

And BTW, this is lower frequency stuff.  The sampling rate is 2KHz and
the primary signal we are looking for is 60Hz (power frequency).


-- 
Russell Senior         ``I have nine fingers; you have ten.''
seniorr at aracnet.com