Hello, regarding the use of AD9910, I would like to ask about BPSK modulation.
I need to use FPGA to control AD9910 and modulate a 50MHz sine signal with a 50MHz M-sequence. At first, single frequency modulation was used, with the profile0 register storing the phase as 0 and the profile1 register storing the phase as π, and then switching pins to achieve phase reversal. However, the effect was not very good after the frequency increased.
Then I tried to use RAM mode for BPSK modulation, and now I want to use RAM Direct Switch Mode with Zero Crossing to achieve it. I have now written two parameters in RAM, 0000_0000 and 8000_0000, to represent the phase values of 0 and π. The starting and ending addresses of Profile 0 are both 0, and Profile 1 is also switched between 0 and 1.But now it's always impossible to achieve, is it because there's a problem with my method? Or did I misunderstand the meaning of phase?
The value I set is
CFR1=A040_0000,
CFR2=0040_0820,
CFR3=1D3F_4132.
Profile0=0800_0500_0000_0008
PROFILE1=0000_0500_4000_4008，
FTW=0CCC_CCCD
Other registers are not set, keep default. I have tried adjusting the parameters of the register, but the waveform is always not ideal and sometimes the phase flip cannot be displayed.
May I ask if there is a problem with my method, the parameter settings, or the need to add some register control? The attachment contains the currently generated signal images and videos.
I hope you can quickly identify my problem and tell me how to solve it. Thank you very much for your help.
