> Danny, > > I am actually using that ADC on a Roach 2 rev 2 board... but Iam using the > same adc calibration for all my spectrometers.. and as I said before, for > the one that planahead was not needed, the dynamic range is fine..
Something that Planahead IS likely to do is change the timing on the signals on the interfaces. This could result (indeed, it seems that it almost MUST result) in the MMCM calibrations being different on the different designs, and we have seen that the MMCM calibration is critical for proper operation of the ADC interface. John > > Regards, > Raul > > 2014-09-16 14:13 GMT-03:00 Danny Price <[email protected]>: > >> Hi Raul >> >> As Dan mentioned, planahead shouldn't make a difference to things like >> dynamic range. If you're using an ADC that interleaves several cores (eg >> 5GSPS ADC), this could be something to do with poor ADC calibration. I'd >> suggest looking into that as a possible cause? >> >> Regards >> Danny >> >>> Raul Sapunar Opazo <mailto:[email protected]> >>> September 16, 2014 at 10:21 AM >>> >>> Hello everyone, >>> >>> I used planahead to fix the timing problems of a 1.8Ghz 32k channel >>> spectrometer in roach 2. I did it without troubles, using 38% of the >>> DSP >>> and less of the 50% of RAMs.. >>> >>> After I compiled the model with the new constrains/placement and I >>> tested >>> the bof, I found out that the numeric noise increased a lot as the >>> power of >>> the harmonics... >>> >>> This issue results in a big decrease of the dinamic range of the >>> spectrometer in the whole BW (around 25 db against 40-45 db of a 1.8Ghz >>> 16 >>> k ch spectrometer that didn't need planahead) >>> >>> I encountered this problem with an 1.8GHz 8k ch aswell.. so the issue >>> is >>> not related with the increase of the number of channels.. >>> >>> Anyone encountered this kind of problems when using Planahead? As I >>> understand planahead shouldn't change the performance because it >>> doesn't >>> make any change in the designs... >>> >>> Any help will be appreciated! >>> >>> Best Regards, >>> Raul Sapunar >>> >> >
