The Radar Receiver

T HE spectacular development of radar during World W a r II remains an outstanding achievement in the history of communications and the allied electronic sciences. With military necessity furnishing the required driving force and through the full interchange of technical knowledge among all interested workers in this field, it has been possible to extend our visual senses far beyond the horizons considered quite inelastic only a few years ago. T h e potentialities of radar in the peacetime world and the f u t u r e application of radar design principles and techniques to the communications and allied fields justify a review of some further details of this wartime development. T h e performance and design aspects of radar receivers will be considered in this paper. For this purpose, the radar receiver will be defined as t h a t assemblage of components within the radar system which is required to detect, amplify, and present the desired information as gathered at the radar location. T h e input signals to the radar receiver consist of radio-frequency pulses containing information regarding the area under observation by the radar system, together with coordinate d a t a defining further characteristics of this observed area. T h e o u t p u t of the radar receiver is most commonly an optical presentation of this composite information, but in certain applications the o u t p u t is further converted into electrical or mechanical signals for specific use. In general, the output of a radar receiver is presented in a form capable of immediate analysis and use.