I got a board from someone else to control the output of the AD9910. When I plugin the power, the board will configure the AD9910 to output 10MHz sine wave. The pseudo code to initialize AD9910 is
MASTER RESET (HIGH)
WRITE FREQ WORD VIA SPI [10MHz]
It is working well.But if I remove the control board, just power up the AD9910 without initialization, I saw a sine wave with unstable amplitude (like a sine wave but the amplitude is slightly moving up and down). I wonder if it is normal to see something like that when power up but not initialization as above? Thanks.