There is not a simple solution so it will take a bit of working out, the AWG buffer would not be suitable as changing frequency would require a rewriting of the buffer.
The option would be to send out a set number of cycles (Shots) of the sine wave at the chosen frequency to achieve a 200ms burst, and have the signal generator trigger on an event which is running at 1sec. It may be possible to do this as a software trigger through Matlab on a timer, but I would need to check this out as Matlab is not my speciality.
Can you please email email@example.com
with the details, I can then discuss this with others in the team.