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Frequency offset between the RXs, AD9361

Question asked by rfkie on Jan 26, 2016
Latest reply on Feb 2, 2016 by rfkie

I encountered a really odd behaviour of the RXs of the AD9361. I hope anyone has  an idea.

 

There is a frequency offset between the two channels RX channels when a

sinosoid signal is fed into both channels from a signal generator and power

divider chain. So both channels sense signals with exactly the same frequency.

When tuned to 1781 MHz the difference between the Channel (f_A - f_B) is

-1.5497 Hz. This is measured by taking the samples from the receiver

calculating the phase difference and determine the frequency difference from

the (apparently linear) phase change rate. At fc = 781 MHz there is a

difference of -0.3576 Hz. Technically there should be no difference in

frequency at all, because the same LO is used (or isn't it?).  Is there a

possibility to configure the LOs in the right way?

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