FPGA Central

Does anyone know of a PSD calculating routine other than in Matlab?

I'm trying to find something I can include into vb 6.0 or vb.net...perhap
a dll, activeX, or the code itself! Unfortunately I'm not versed in th
realms of PSD enough to write my own. I do use a routine from nationa
instruments DSP toolbox called Auto Power Spectrum which gives the aut
power spectrum (whatever that is) in E.U. rms^2 (like G rms^2). Would i
be correct to say there is a way to convert this to G rms^2/Hz? I have a
fft routine that I can use in the calculation if necessary. Any help woul
be greatly appreciated.

Thanx,

B

"Bum" <[email protected]> skrev i en meddelelse
news:[email protected] ...
> Does anyone know of a PSD calculating routine other than in Matlab?
>

I assume you are familiar with complex numbers.

If you have a sequence x of numbers where x(1) is the first number and x(N)
is the last number in
your sequence then you can calculate the power spectrum X like this:

for k=1 to N
tmp_sum=0
for n=1 to N
tmp_sum=tmp_sum+x(n)*exp(-j*2*pi*(k-1)*(n-1)/N)
end
X(k)=abs(tmp_sum)^2
end

It's not an optimal way of doing it, but it's straightforward and easy to
understand.