The DG108 is a PCI card having 6 delay lines that can produce delayed signals from 50nsec to 419 sec in steps of 25psec.
A trigger circuit starts the delay counters. There are 4 counters, T, A, B and an auxiliary counter. The T, A and B counters actually produce an output signal, while the auxiliary counter can only be used to produce an interrupt. In Pulse-Mode each programmed delay produces a pulse of specified length at its output connector, in Edge-Mode the first level transition is determined by the first programmed Delay – after the last Delay expires all outputs are reset together. In Gate-Mode the outputs A and B can be combined to form a gate signal, i.e. a rising (falling) edge after delay A has elapsed and a falling rising edge after delay B has elapsed, so you get an pulse with a variable(25ps resolution) pulse width from 2ns – 429s.
The trigger can be produced internally by a modulo-N counter or by an external signal. The signal connected to the external trigger input can also be used as external clock, and can additionally can be gated and prescaled.
If more than 6 Outputs (or more than 1 Gate output) are needed, two ore more cards can be connected together via a ribbon-cable, resulting in 6 or more synchronous delayed outputs.