Question on using UHD Source Block to transmit accurate PM signal

Hi,

I would like to use the N210 LFTX daughterboard to transmit bi-phase
modulated signal. The phase switching need to be done accurately in a
real-time sense, that is, the switching times has to be as accurate as
possible, which means it should be controlled by the master clock of the
N210.

From Gnuradio, I see the UHD source block. But it doesn’t take any
input. My
question really is: Gnuradio does things on the host computer, but the
right
thing to do is to do the real-time phase modulation on the LFTX
daughterboard, to ensure hardware-controlled timing performance.

I don’t see a clear way to do this from the gnuradio interface. Are
there
any code examples or examples similar to the hardware-control aspect?
Maybe
people have done some python code that performs this kind of board-level
manipulation that is controlled by the master clock?

Thanks,

LD