Hello,
I hope somebody can help me.
First my configuration:
Cyclone III Starter Kit
FFT v8.0 with 1024 points
burst
14 bit resolution
32MHz clock
2MHz output clock (after FIFO)
Ok, how should I start. I've got two problems:
1. the reset!
When do I have to do a reset? Once after programming the device, e.g. pushing a button? Or after each FFT run?
2. the scaling!
I read many facts about that, but I think I didn't get it right now. At the FFT User Guide I read the implementation and I don't know, if I understood that right:
example:
14 bit full range, 4 bit (1001) word, shifting 4 times
result:
111111 1001 0000
100000 1001 0000
000000 1001 0000
Which of these results is the correct one?
I programmed my device and put a sinus on the ADC-board. From here it goes onto the FPGA, into the FFT-real-input.
My results look like the attached picture. The MSB are always "1" or "0" at the same time :confused:
I tried so much and I don't know what to do more. I also attached my "shifter.vhd"-file, which handles the scaling.
Thanks for your help!
Lars :(
