Timing delay jitter problem

Unfortunately, we could not resynchronize the TWINAMP using the two separated trigger pulses. I think the large RMS jitter from BNC 7010 digital delay generator makes the synchronization failure. So I replaced the BNC generator with SRS DG-535, the TWINAMP ran steadily. DG-535 has only 50 picosecond RMS jitter. The best way to eliminate this jitter is to control 4 channels of DG-535 by computer. If we buy a GPIB-RS232 converter from NI, it's easy to communicate with only one DG-535 for switching on or off the trigger signals("out 1" and "sync out").