FFT need help

[Altera_Forum]

Hello, 

 I'm working on quartus for a project and I have to create an FFT block, but I never work on Quartus and I don't understand how I can link it. I just want to create a generator and an FFT, but I don't know how link them.  Someone can explain me the input/output of FFT block ?  Thanks  PS: Sorry for my English, I'm french.

[Altera_Forum]

Hello, 

 You can find all the information about the FFT in the FFT Megacore Function User Guide (http://www.altera.com/literature/ug/ug_fft.pdf). Take a look on it, and come back if there are still things that are not clear.  Jérôme

[Altera_Forum]

Hello, 

 Thanks for this document, but I have still problems :p  For the clock it's ok, I understand what it is. But then ... Reset_n : it's for reset the FFT before get a new signal ?  I don't understand what are the sink_*** input (or output maybe). What is their utility ?  And for the source, how I must link it to the FFT ? I think I have to use source_real and source_imag but I don't understand the difference between these input.  The source_valid and source_ready, I think it's ok.  So if someone can explain me what are the inputs I have to use to get my signal in the FFT, and the utility of sink_*** I/O, it will be very good :D  Sorry if it's explain in the pdf, but I don't understand everything.

[Altera_Forum]

For the reset, it is a classical reset signal, just set it to 0 at the start up of the system, and then 1. 

 sink_real and sink_imag is your input signal.  sink_valid is a kind of enable to tell to the FFT that there is signal at its input. sink_sop/eop is to tell to the FFT when to begin and when to finish, thats corresponds to the begin of your signal and its end. (see Fig 3-4)  sink_ready is set by the FFT to tell you if it can process data or not. It is not useful for streaming architecture (see Fig 3-3), but it is for the buffered ones (see Fig 3-11 and 3-14).  And the source_* are the equivalence of these signals for the output.