by glen herrmannsfeldt <gah@[EMAIL PROTECTED]
>
Oct 12, 2008 at 07:50 PM
Peter123 wrote:
> I have implemented Jens Joergen Nielsen FFT code in my windows program
> that converts V(t) to V(f). I am using 2500 Hz sampling with N=8192
point
> FFT.
> I am plotting the FFT amplitude as sqrt(Re^2 + Im^2)/N. Im getting the
> correct peak frequency after FFT, however, I am getting only about 1/2
of
> the peak amplitude (of the input sine wave input amplitude) with
> rectangular window. (If my input wave is 20.0*sin(omega*t) the FFT gives
> ~10 for peak height at omega).
> Using various windows (Hamming, Bartlett, etc) the V(f) peak amplitude
> becomes even smaller.
>
> Any suggestion why do I get 1/2 peak heights?
Are you also including the part at V(-f)?
-- glen
