Unambiguous frequency measurement in a scanning superheterodyne receiver

Frequency is the single most important measurement for signal sorting and emitter identification in electronic support measures (ESM) receivers. There are a variety of techniques for making frequency measurements on radar signals. The authors describe a low-cost technique which may be applied to a scanning superheterodyne receiver. The technique has become applicable to ESM receivers as a result of developments in fast tuning, broadband voltage controlled oscillators (VCO) and has been demonstrated in a receiver covering a 3 to 1 bandwidth