The PG 508 is a 50 MHz general purpose pulse generator usable in all TM 500 series power modules except the TM 501. Major capabilities of the instrument include independent period, delay and duration controls. The instrument also features leading and trailing transition time controls as well as independent pulse top and bottom level controls. Custom positions on the period, duration, delay and transition controls allow customer determination of parameters for these control ranges. A control error light indicates improper control settings such as excessive duration, delay, or transition times. Front panel controls and connectors provide an external trigger and duration or synchronous gate input with level and slope selection. Also provided are manual trigger or gate capabilities, delayed or paired pulse capability, square wave output, pulse complement, and preset output levels. All outputs are internally terminated in 50 Q. The trigger-gate input impedance is internally selectable for either 50Ω or 1 MΩ paralleled by approximately 20 pF.