The design of a PC-based, low-cost radar video signal generator

In the field of electronic warfare (EW), the development, test, validation, and debugging of radar warning receiver (RWR) hardware and software in the laboratory necessitates the simulation of radar threat signals. This requirement often leads to the development of expensive, high-fidelity, radio frequency (RF) simulators. Because they are expensive, they are scarce. They are also often hard to configure, operate, maintain, and relocate. Moreover, they are frequently in heavy demand, and engineers can rarely utilize them for lower priority, everyday design and debugging tasks. This paper describes the design of a PC-based, low-cost (<$2500 parts cost) radar video signal generator (VSG) circuit card assembly which provides four independent, scan-modulated pulse waveform channels. Each of the four channels is capable of producing a waveform consisting of over 4000 pulses, allowing highly complex waveforms containing stagger and jitter to be defined. Its output signals are in the video domain, not in the RF domain, and although it cannot replace large scale simulators for complete or formal validation testing, it provides an inexpensive, easy-to-use, easily transportable tool capable of supporting engineering and debugging tasks. The VSG card is hosted by a single AT-bus slot of an IBM-compatible PC, and is controlled via a Microsoft Windows-based Graphical User Interface. Run-length encoded pulse and scan waveform data are converted and combined into analog signals compatible with the video input stage of the AN/ALR-69 RWR. This can eliminate the need for RF signal generator hardware entirely, or can allow VSG-generated signals to augment RF-generated signals when RF simulator hardware is available. The VSG hardware and software were designed and are in use at the Georgia Tech Research Institute as part of an effort for Wright Laboratory to improve and enhance test tools available for the evaluation of Radar Warning Receivers.