I'm now testing AD9779A-DPG2-EBZ evaluation board.
It has TxDAC AD9779A and IQ-modulator ADL5375-05 onboard.
Modulation data stream is generated from external FPGA and LO input comes from ADF4350-EB1Z.
Generated RF spectrum works as expected, but output power level seems lower than the value
in ADL5375 datasheet as LO frequency goes higher.
Measured values are as follows;
ADL5375 datasheet says Pout is between 0dBm and 1dBm in frequency range 0.45-3.5GHz.
I suppose Viq level is tuned in the evaluation board, and LO level from ADF4350-EB1Z is in appropriate level.
Any comments on the cause of loss and methods to improve S/N are highly appreciated.