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FMCOMMS1 Synchronization

Question asked by ROBFRO on Dec 19, 2013
Latest reply on Jan 13, 2014 by rejeesh

Hello Guys,

 

1) I have 2ea XILINX ML605 boards and 1 FMCOMMS1 board on each of these development boards.

2) I started with the demonstration project, and added our own Transmitter and Receiver logic.

3) I can transmit and receive on the same board, and I see the baseband projection locked, not rotating. I am looking at the raw ADC input to the FPGA using CHIPSCOPE. 

4) When I cross from one ML605/FMCOMMS1 to another ML605/FMCOMMS board the baseband projection is rotating at a pretty good rate.

5) My CARRIER is 1.5 GHz. DAC = 196608000, ADC = 32,768,000.

6) TX to RX on a single board, I have 0 BER, through an antenna.

7) TX to RX, board to board, we can't decode the data properly.

8) The rotational speed we are seeing is around 360 degrees in 8192 samples (32,768,000 samples / second).

9) We tried using the same 200 MHz reference frequency in to the XILINX, which in theory gives us identical 50 MHz reference frequencies into the ADI board. This didn't seem to have an effect.

10) The attached file is the ADC output, sampling at 1/8 of the ADC Clock Frequency ~4 MHz.

 

Any ideas....

 

Rob Froyd

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