Programming AD6654 in IF RIO

[jkrama]

Hi Jerry,

We are trying to use PXI5641R and in that we need to programe AD6654.  We are using  48.96 MHz clock (ext ref clock)  for ADC and down conversion factor is 256. Thus our base band samples are at 160 KSPS. If we look at Base band samples, they are rotated by big number and it is not just delta offest which can be corrected.  If we look at constellation diagram, data (I.,Q) getting rotated full circle ( clock wise) many time. May be for every 10 to 15 msec one rotation. I think, i dont understand to programe AD6654 to get correct result in which there is no Frequency offeset because of NCO. could you kindly look at this question. 

Kind Regards

jk

[JerryAL]

Hi JK

Can you attach a picture?  And maybe your project?

J

[Vojtech_D.]

Hi JK,

I can tell from the experience with the 5640R + PXI 5610 + PXI 5600 that a rotating constellation diagram comes from not sychnronized transmitter and receiver. Are you using PXI 5641R only?

Best regards,

Vojtech