DDG200 Interface Technology Digital Delay Generator

The DDG200/400 Digital Delay Generator is a C-size, register-based VXI instrument with programmable delay and width parameter memory behind each channel. The instrument provides two (DDG200) or four channel (DDG400) output pulses with variable delay and width, and programmable pulse amplitude. Pulses can be used to gate an RF synthesizer to control the delay and width of RF pulses, or it can be used for precise sequence timing of experiments, tests, and similar applications. Pulse and delay parameters are programmable with 1 ns resolution over a wide range of values. Both internal and external pulse-triggering modes are provided. The four individual pulse outputs are controlled by a user programmable “scenario table”, containing individual delay and width parameters for each output channel. The scenario table is capable of containing up to 500,000 individual delay/width settings per channel. All internal timing is derived from a highly stable, ovenized 10MHz crystal oscillator reference.

The DDG200/400 can be triggered either internally by a 100 Hz to 1 MHz programmable clock, from an external trigging source, or from the VXI TTLTRG bus. It can also source signals to the TTLTRG bus to synchronize instruments across the VXI backplane. The delay from trigger to pulse output is programmable from 270 ns to 4 ms while pulse width is programmable from 50 ns to 1 ms. Pulse amplitude is programmable from -2 to +5 Vdc into 50 Ω. The DDG200/400 is a new class of instrument specifically designed to provide test engineers with a flexible timing tool to aid in the generation of complex radar pulse simulations. When combined with an IF or RF source, the DDG200/400 can be used to control the timing of pulses to a radar receiver, simulating target movement or terrain variations. Multiple timing channels allow the DDG200/400 to control the simulation of multiple signals, useful for simulating multiple targets or in Electronic Counter-Measure (ECM) simulation.