peppiniello
Structural
- Oct 16, 2001
- 32
Hi to all
who can tell me the normalisation criterium Excel uses calculating the Fast Fourier Transform FFT(Sn), where Sn is a discrete signal?
What i do to obtain the FFT amplitude is the usual evaluation of the complex modulus of the FFT complex array
what i find is:
the original signal Sn has two main armonics, one of which (f1)has a peak of 100
but FFT(f1) is 60000 rather than 100!!
why?
moreover:
doin FFT on the same signal using first Excel , than Mathcad
i find :
Mathcad FFT amplitude = about 50 times Excel FFT amplitude
why again?!
who can tell me the normalisation criterium Excel uses calculating the Fast Fourier Transform FFT(Sn), where Sn is a discrete signal?
What i do to obtain the FFT amplitude is the usual evaluation of the complex modulus of the FFT complex array
what i find is:
the original signal Sn has two main armonics, one of which (f1)has a peak of 100
but FFT(f1) is 60000 rather than 100!!
why?
moreover:
doin FFT on the same signal using first Excel , than Mathcad
i find :
Mathcad FFT amplitude = about 50 times Excel FFT amplitude
why again?!
