Meaning of output value?

[Sander Odekerken]

Hello everybody,

For a school project I use the Xilinx Coregen FFT core. It does work, but
what does the output mean? Is the Real output the amplitude and the
Imaginary output the phase?

If anyone knows, please HELP!!!

thanks,

Sander Odekerken

 

[Symon]

Hi Sander,
http://www.dspguru.com/info/tutor/quadsig.htm
Cheers, Syms.

 

[John_H]

This is an extremely basic question about complex math.

Real and Imaginary number pairs make up a cartesian coordinate pair. Think
of the real part as the x-axis and the imaginary part as the y-axis.

Amplitude and phase values produce a polar coordinate location. Think of
the amplitude as the distance from the (x,y)=(0,0) origin and the phase as
the angle counter-clockwise from the x-axis.

The conversion from cartesian to polar comes from:
amplitude^2 = x^2 + y^2
tan( phase ) = y/x

I hope your FPGA work doesn't get hampered too much by your limited
engineering-math knowledge. Good luck with the project!