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ad9528 frequency offset

hello, I am using a custom adrv9009 with a custom zcu102 board. we have used a VCXO of 122.88MHz with a frequency stability of 50ppm. when I try to receive a signal on the RX path of my custom adrv9009 there is an offset in the received frequency. I am using a signal generator to generate a sinewave of 30MHzand checked it for frequency offset, there is no frequency offset in the output of the signal generator. And when I use reference adrv9009 board there is also no offset. can someone tell me how to resolve this issue? what do we have to do to minimize this offset in the received frequency. the offset increases with the increase in LO frequency and with temperature.

  • If your devices are not frequency locked they will have drift differences. This is where the 50ppm number comes into play, and scales with frequency.

    There is no way to "fix" this issue as oscillators will naturally have differences based on their specifications. You could replace the oscillator with one that has better initial accuracy and drift performance, or calculate what the offset is and apply a correction factor. Note that the offset will be random and change over time.