Toward an Optimum EMC Receiver

Opinions of what a universal EMC receiver should do, and differences on how such a receiver should be constructed are quite diverse. These ideas depend on users, operators, designers, and engineers and their training and knowledge. When considering the input requirements, decisions must be made on frequency coverage, bandwidths, input levels, amplification, and antennas. Detection schemes, calibration signal provisions, scanning speed, and the requirement for multiple active heads must be studied. An optimum IF, or more than one IF, may be required as well as BFO\´s, box-car pulse stretchers, pulse duration timers, prr counters, and DF circuits. Received information can be best processed by computer methods. Direct association with a small general purpose computer may protect from obsolesence and increase reliability. The major intended use determines the outputs. These may vary from go, no-go lights through meters to sophisticated oscilloscopes and XY plotters. The more complex instruments may have memories of a suitable type, or they may use the memory of an associated signal processor. Many functions must be automated; human engineering, total circuit complexity, and reliability enter here. To obtain many of the wanted features, modular construction is suggested. For extremely weak energy detection, remote sensing is applicable; results can be telemetered to the receiver. In the future it is probable that the complete receiver will be built inside the antenna. Extremely wide bands will have to be measured; circuitry capable of resolving and analyzing extremely complex phase and "noise" modulation techniques will have to be designed.