The DD 501 Digital Delay is an events counting plug-in
unit designed for use in a TM 500-Series Power Module mainframe. Separate
external trigger signals are connected to the EVENTS and START INPUT connectors
allow up to 99,999 events to be counted. That is, the unit counts a
predetermined number of events, from 0 to 99,999, selected by the front-panel
thumb-wheel switches. The last event counted generates a trigger pulse to the
DLY'D TRIG OUT connector on the front panel. Delay by event is particularly
useful in troubleshooting asynchronous logic systems. The DD 501 can also
function as a frequency divider when the same signal is applied to both inputs.
The DD 501 can be used in a "counted burst" mode with pulse or
function generators that can be synchronously gated. This provides the ability
to dial up the number of pulses you want in a burst for applications with shift
registers, memories, data communications, process control, or any system
requiring an exact number of pulses or waveforms. A jumper inside the DD 501
converts the DLY'D TRIG OUTPUT to a delay interval (gate) waveform for this
application. TEKTRONIX generators capable of being gated by the DD 501 are the
FG 501, FG 502, FG 504 and the PG 508.
Other DD 501 applications include ranging for radar, sonar, ultrasonics, or
laser. By using the proper frequency clock, the numbers dialed up can represent
miles, yards, kilometers, etc. In systems requiring precision timing. several
DD 501s and a reference clock can provide precise thumbwheel-selectable
repetition rates, delays, pulse widths, or timing intervals.
