Frequency Error between LO1 and LO2

 jak_ub It sounds like you want some kind of formula that you can calucate/predict the frequency error based on NCO offset, could you confirm? ADI does not provide any formula or guidelines for this behaviour if that's your question. Could you clarify how you measure 1Hz error, and your target performance? It'd be helpful you provide more details about your application along with your requirement. 

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 jak_ub It sounds like you want some kind of formula that you can calucate/predict the frequency error based on NCO offset, could you confirm? ADI does not provide any formula or guidelines for this behaviour if that's your question. Could you clarify how you measure 1Hz error, and your target performance? It'd be helpful you provide more details about your application along with your requirement. 

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Thank you for the reply. I think that you understand correctly: Given that LO1 used for Rx1/2 with chosen (arbitrary) NCO at a specific carrier frequency, I would like to set LO2 used for Tx2 such that there is no frequency error in the baseband signal. This can be measured by transmitting CW signal on Tx2 and recording it on Rx1/2 in the block diagram above. Frequency error can be then evaluated on the recorded Rx1/2 IQ samples. If there was zero frequency error, recorded IQ samples should be perfectly constant. We do not have a specific target, just as low as possible.

For communication between two IC's, frequency offset compensation is often necessary: evaluating a single IC, I hoped to avoid the necessity of this process in our system. 

Is the problem clear now?

I understand that you do not provide detailed guidelines; we will thus measure the error and compensate it as a workaround. Thank you!

Thank you for your understanding, and I hope your workaround works well. Please let us know if you need any further assistance.