AWR1843BOOST: AWR1843 phase shifter

Hi ,

According to AWR1843's datasheet, I found that:

  "The AWR1843 transmit subsystem consists of three parallel transmit chains, each with independent phase and amplitude control. All three transmitters can be used simultaneously. For AWR1843, additional phase shifters are associated with Tx channels, and these can programmed on a per chirp basis."

This is a very important function for us, but I did not find some detailed instructions. Can you introduce me to the detailed control method? 

Thanks,

Best wishes