Altera FFT IP-CORE core version 9

Hi Jean:

I'm just running out of the office, so I'll post some more tomorrow:

In layman's terms, the twiddle factors are basically sin()/cos() table lookups used in the fft calculation. I'm sure a math guru would have a complicated explanation, but that's the simple answer. The size of the table is dependent on the size of the FFT, and the size of the and in general the more points you are doing the more number of bits you should have in your twiddle table.

I don't have anything off the shelf, but it's not too complicated to do. I'll dig up a doc tomorrow on it. In general unless the Burst core is different the core should like everything in natural order, so you should only require this if your source data for your IFFT is in reverse order.

I'll dig up a doc, and send you what I have tomorrow. I happen to be writing a FFT core now for an asic conversion, so I have a few around.

Pete