ps: even when I run the test_adc5g.py with digicom_r2_2500MHz.bof with 2500MHz oscillator, the calibration still failed.
On Fri, Jan 31, 2014 at 10:11 AM, Weiwei Sun <[email protected]> wrote: > Thanks Jack and Rurik, > > When I calibrated mmcm phase, it didn't find the optimal mmcm phase. Why > is that? and any ideas of how to correct it or what I should look at to fix > the problem? Thanks! > > Weiwei > > > On Thu, Jan 30, 2014 at 4:04 PM, Jack Hickish <[email protected]>wrote: > >> On 30 January 2014 23:56, Primiani, Rurik <[email protected]> >> wrote: >> > Hi Weiwei, >> > >> > Have you calibrated the MMCM phase using test vectors? The following >> > repository hosts Python/corr code that may be helpful to you: >> > >> > https://github.com/sma-wideband/adc_tests >> > >> > I've recently updated the README, please see the "Calibrating the >> > data-to-clk" for instructions on how to use the code. I believe this may >> > correct the bit errors you're seeing. Note: this code assumes that your >> > bitcode has a snapshot hooked up to your raw ADC output _after_ it's >> been >> > converted to signed two's. >> > >> > Alternatively there is some code out there (I believe written by Jack >> > Hickish) that adjusts the IODELAYs on each data bit to correct for >> capture >> > errors. >> > >> >> Just to say, this code is in a fork of the sma repo, at >> https://github.com/jack-h/adc_tests >> But you won't need to calibrate per-bit unless you're running the adc >> near full speed, and even then, you could probably get by without. >> >> > Lastly, please keep in mind that this ADC has four interleaved cores >> each >> > with their own phase, bias, and gain differences. These may need to be >> > adjusted as well depending on your application. >> > >> > Best, >> > >> > Rurik >> > >> > On Jan 30, 2014 6:36 PM, "Weiwei Sun" <[email protected]> wrote: >> >> >> >> Hi Rurik and Casparians, >> >> >> >> I have a problem with the data out of the adc5g yellow block and 2's >> >> complementary change and captured by a snapshot. It seems there is bit >> >> errors during the transmission, or it could be some other problem. >> This is >> >> roach2 with an adc5g clocked at 1400MHz, 2-channel, Nondemux (1:1) >> mode. >> >> >> >> I tested it with a 175MHz sinusoid wave generated by a signal >> generator. >> >> The samples are predicted to be constant for every stream of the total >> 8 >> >> output streams with amplitude 32 within range (-128, 127), but I saw a >> lot >> >> of bit errors (bit flip? ). Attached are the time series of the 8 >> streams. >> >> Has anyone experienced this weird data? I'm appreciated of your >> attention >> >> and advice! Thanks! >> >> >> >> Weiwei >> >> >> > >> > >
