I'm trying to setup the AD9789 eval board for generation of single-tone signals in a part of TVWS band from 512 MHz to 602 MHz (the center frequency is 557 MHz). In order to do this I activated QDUC mode, turned off channels 1 to 3, bypassed QAM mapper, SRRC and interpolation filters, wrote P/Q equal to 1. THe DAC clock in my setup has frequency of 16*(557MHz/4) = 2228 MHz. I hoped that by setting the BPF center frequency to 557 MHz and changing the NCO frequency between 0 to 45 MHz (positive offsets from 557 MHz) and FDAC/16-45 to FDAC/16 MHz (negative offsets from 557 MHz) I would be able to cover the whole desired band. Everything works as expected except that I see a strong image spur when the offset from 557 MHz is more than ~30 MHz. The level of the spur achieve -30 dBc at the band edges. I would be very grateful if anyone could tell me what am I doing wrong.