Comments:
-The FFT is probably fine. If it was broken, it would probably be 100%
broken. At least this looks like a spectrum
-It appears to me as if the broken section is exactly 1/8th of the
spectrum. Did you hook up all of your outputs correctly?
-What's up with the spikes in the spectrum? If they were interleave
artifacts, I'd expect to see the one which is at channel ~1800 closer to
2048. Maybe they are some other tone though
On 03/15/2013 12:14 PM, Nimish Sane wrote:
Hi all:
I am attaching a plot for Power of two inputs vs frequency channels.
As can be seen, we have this persistent problem where some channels at
the end just do not make any sense. We suspect that there is something
going wrong in the FFT block. Has anybody seen such behavior before or
can think of what may be going wrong?
Following are some specifications that may be useful:
Hardware: ROACH2 with KATADC.
ADC Clock: 800 MHz,
FPGA clock: 200 MHz
Toolflow: XSG 11.5 with Matlab 2009b with RHEL5.8
Libraries: SKA
FFT green block: fft_wideband_real
FFT size: 2^13 (4096 Output channels)
Thanks,
Nimish
--
Nimish Sane
Center for Solar-Terrestrial Research
New Jersey Institute of Technology
University Heights
Newark, NJ 07102-1982 USA
Tel: (973) 642 4958
Fax: (973) 596 3617
nimish.s...@njit.edu <mailto:nimish.s...@njit.edu>
