I am using the AD9789 clocked at 2240 MHz and programmed in QDUC Mode to generate a 100MHz-900MHz modulated signal. Baseband signal I,Q is provided by a FPGA with a LVDS interface. So far it works fine.
Yet I have noticed a strange phenomenon : On a frequency change a wideband glitch appears in RF exactly at the moment the Frequency Update Register @0x1E is set to 0x80, even though the INSCALE and SUMSCALE registers are set to zero.
I have no control on this glitch and it might damage the high power amplifier that follows our modulation system.
1/ Are you aware of this glitch phenomenon ?
2/ Is there a way to suppress it ?
Thanks in advance to those who can help