Hi Bob, Thank you for your answer. Yes, calibrating the 8-bit 5-GSPS ASIAA ADC is a must! I worked on that some time ago. I always make sure that the 4-cores OGP and IODELAYS calibration residual error is within a acceptable range before starting any data acquisition.
We also have checked the whole LNA chain linearity and it is fine, there is no harmonic distortion. So, we narrowed down the problem to the fact that we do not have enough dynamic range in the ADC to accommodate the RFI, avoiding clipping, and simultaneously having enough bits (>2) when looking to a clean reference load. Thank you again, XB On Mon, Dec 11, 2017 at 2:16 PM Wilson, Robert <[email protected]> wrote: > Hi Xavier, > > One problem with the the 8-bit 5-GSPS ASIAA ADC board is that the ADC has > four cores and if they are not exactly aligned, a strong RFI signal will be > modulated by and mix with the periodic errors producing a number of > artifacts. > > Bob Wilson > > On Thu, Dec 7, 2017 at 5:10 PM, Xavier Bosch <[email protected]> > wrote: > >> Hi CASPERites, >> >> >> >> We are developing a wideband spectrometer (~1.6 GHz ) in a band that has >> a lot of RFI. Currently we are using the 8-bit 5-GSPS ASIAA ADC board and >> the ROACH2, and the ADC resolution appears to be inadequate for our extreme >> RFI environment. >> >> >> >> We would like to move over to a higher resolution ADC (12 to 14 bits), >> probably with a JESD204B interface, and a Xilinx development kit. We are >> considering something like this evaluation board KCU105 >> <https://www.xilinx.com/products/boards-and-kits/kcu105.html#hardware>and >> something like FMC217 >> <https://www.vadatech.com/product.php?product=528&catid_prev=0&catid_now=0> >> as a digitizer. >> >> >> Has anyone been in a similar situation dealing with RFI? >> >> Has anyone ported CASPER library to Xilinx development kits and JESD204B >> ADCs? >> >> >> Thank you, >> >> XB >> >> -- >> > You received this message because you are subscribed to the Google Groups " >> [email protected]" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> > -- > You received this message because you are subscribed to the Google Groups " > [email protected]" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > -- You received this message because you are subscribed to the Google Groups "[email protected]" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected].
