Altera FFT IP-CORE core version 9

Hi Jean:

http://www.dspguide.com/ch12/2.htm

has a pretty good description on the bit-reversal. Basically all you need to do is read hook up the address bits in reverse order, and you are good to go. IE if the data is in a ram block in bit reversed order, if you hook up the address bits backwards on the read port so instead of A7,A6,A5,A4,A3,A2,A1,A0 and they are hooked up A0, A1,A2,A3,A4,A5,A6,A7 you will get the data back in natural order.

I should have remembered this, but I'm working on a Radix-4 engine, so it's slightly different, In that case you "Digit-Reverse" the addresses 2 bits at a time, so in this case,

instead of A7, A6, A5, A4,A3,A2,A1,A0 it's A1,A0, A3,A2, A5,A4, A7,A6.

Pete