Calculation of phase and Amplitude of an IF signal

[yasine79]

Hello all,
when i have an IFsignal, i know the method to calculate the Amplitude and the phase. First the I and Q componenent should be calculated,this is achieved with downconverting the IF signal digitaly DDC.
Amplitude=sqrt(I^2+Q^2). phase=atan2(Q/I).

my quuestion is: is it possible to calculate the amplitude and the Phase of the IF signal with FFT?
what are the adventages of the FFT in this case?

Thank you

 

[KlausST]

Hi,

Yes with an FFT you can calculate phase and ampltude.
The advantage of the fft is that you calculate relatively fast the real and imaginary part of a lot of frequencies.

If the desired frequency is known i'd prefer dft here.

Klaus

 

[yasine79]

thanks for ur reply. I wonder why in the literature the most discussed topic for calculating the amp and phase from an IF signal is the calculation of I and Q. Do u know any literature discussing this topic with DFT for heterodyne (or homodyne) receiver?

thank u

 

[axcdd]

there are always quadrature recivers because in examples survillence radars information that u gain from dtf - frequency and amplitude - is not enought - signal has to match some pattern - ex. pulse width ( rising, falling time).