BPSK for AD9152

Hello ! I am using fpga + DAC AD9151 to generate analog signal. 

Digital data from my DDS core are sent via JESD204B interface to DAC and i can see analog harmonic signal on an oscilloscope. 

So i conclude that DDS and DAC is working correctly.

Next step is to modify core to generating BPSK pulse according to a given digital sequence. 

For example i send phase shift of [0; 180] degrees (+1; -1) for I component and (0;0) for Q component. 

I expected to see analog phase modulated signal, but i saw something similar to DSB signal. I assume that the modulating sequence is wrong. 

I have done similar cores before, but for DACs without analog quadrature modulator inside (AD9152 have aqm ADRF6720) and my plan worked correctly.

So the question is how to send digital data for specific DACs with AQM onboard - in my case AD9152 - to get  phase shifted analog signal?

  • Hello,

    Comment below is only about IQ Modulator related , ADRF6720.

    When you generate BPSK signal at 0 and 180 phase, then it is not I and Q that is in phase and quadrature phase(0, 90). Once I and Q signals (at 0, 90) are applied to Quadrature Modulator like ADRF6720, there will be single-sideband signal at Modulator output. But if you feed  these BPSK signals to AQM(actually that expects quadrature baseband signals, not BPSK signal) , you will see double-sideband signal, not SSB. We don't have BPSK Modulator.

    Thanks

    Tony