Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Altera_Forum
Honored Contributor I
724 Views

FFT need help

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.
0 Kudos
3 Replies
Altera_Forum
Honored Contributor I
30 Views

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
Honored Contributor I
30 Views

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
Honored Contributor I
30 Views

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.