Does it work my fft program?

[zoon]

I am trying to make a basic FFT program, but I can't find anything similar my case in the website. I just want to extract FFT modulus and phase from the FFT.vi. To test my fft program, I synthesize the 2 sin wave with different frequency and phase. It's about 1000Hz sampling. Phase difference was 90 degree. Then the raw data put my fft program. I think zeroth harmonic might be 0 phase degree, but in my program, it was not 0 phase degree and there were so many phase harmonics excluding my interested 2 sin frequency.
Please check the validity of my fft program about modulus and phase. I am attaching my fft program.

Thanks in advance

from zoon

[Cyril]

Zoon,

Please find attached a modified version of your VI. I just generated 2 sine waves of different frequencies and with a phase difference of 90 degrees.It works fine. Just dont' forget that the phase diagram is the phase of the composite signal and that you would need a cross spectrum analyser to see the difference of phase between the two signals. Moreover, I think you used the complex FFT and you were probably analysing real data.

Regards,

Cyril Bouton
Applications Engineer
National Instruments