The Tektronix 3T5 is a remotely programmable sampling sweep, mainly intended for the 568 system, but usable on other 560-series scopes. The auto triggering circuit in the 3T5 was designed by Murlan Kaufman.
It has a digital input that controls a digital timing delay. This allows the window of time that is displayed on the scope to be delayed.
The programmable delay is implemented using an internal 10 MHz clock, a counter, and a digital comparator.