Tendencies in the design of the communication type of receiver

The term ¿communication receiver¿ is sufficiently vague to demand some measure of definition. The first Section of the paper therefore discusses briefly the historical background and the features and applications of the type of receiver which, to the best of the authors´ knowledge, are generally accepted as being implied by this term. The second Section covers the mechanical considerations which apply to (and to some extent limit and define) the complete receiver. The third Section, in which it is hoped that the main interest of the paper will be found, discusses the electrical features of this type of receiver. From a brief review of overall circuit considerations, it passes to a discussion of specific characteristics, dealing in some detail with the extent to which theoretical limits of signal/noise ratio are achieved in representative designs. In addition to treating the factors limiting such fundamental characteristics as signal/noise ratio, selectivity, etc., this Section gives some attention to such ancillary features as electrical band-spread methods, listening-through facilities, etc. In the discussion of both the electrical and the mechanical features of these receivers, the object has been to give a critical survey of the nature of the design problems and the solutions adopted in typical receivers, rather than to cover detailed design information in connection with any particular feature. The paper concludes with Sections devoted respectively to current practice in supply-circuit arrangements and possible future tendencies.