The Type 1217-C Unit Pulse Generator is a general-purpose pulse source intended primarily for laboratory use. The repetition rates of the pulses may be either internally controlled, at frequencies from 2.5 cps to 1.2 Me, or externally controlled at frequencies up to 2.4 Me. In addition to the main positive and negative output pulses, the instrument also supplies synchronizing pulses that correspond to the beginning and end of the main pulse. The early sync pulse (“prepulse”) is intended chiefly for synchronizing an oscilloscope while the late pulse (“delay” pulse) is intended to make the instrument an accurate time-delay generator.