How to TX burst data from file, at specified time

I would like to receive a suggestions of yours on which is the simplest
way to transmit a burst of data, at specific time, using USRP N210. I
am planning to input 1pps & 10 MHz to the USRP, in order to have the
start of burst accurately synchronized to the external 1pps (for me
accurately means with a jitter of less than about 100 ns).

I saw that there are some examples in the UHD and GR documentation, but
I wasn’t able to understand how to use them. Please consider that,
until now, I am able to design a system using GRC, I am just able to
create my own GR block (I just followed the example on how to create an
out-of-tree module), but I am not able to do any more.

Is there any way to design what I need using just GRC? No one created
such a block in GRC?

Best regards


Perhaps the solution to my question could be a code modification of one
of the following examples:


in order to start a transmission of a burst, got from a file, exactly at
the 1pps pulse.

Could some one suggests how modify the above example codes?