Faithful reproduction in radio-telephony

On account of the great number of processes and transformations that energy undergoes between its acoustical source and the ear of a listener when wireless telephony is the means of transmission, it is not possible in a single paper to explore in detail all the avoidable and unavoidable possibilities of distortion. The proper understanding and application of certain general principles enable individual circumstances to be examined and indicate the path to be taken in the pursuit of high-quality transmission. In this paper, therefore, an attempt has been made first to define terms suitable to the scientific study of faithful reproduction, second to analyse into separate constituents the types of distortion occurring, and third to la)´ down the general principles above referred to and give them as far as possible a mathematical form. This has been done not only for the purpose of ensuring precision and definiteness of statement, but also to enable quantitative application to be made and to prepare a foundation on which to build as knowledge of the subject progresses. Special consideration has been given to transient phenomena because in much of the apparatus used for radio-telephony the ordinary forms of steady-state distortion can be reduced to a negligible amount. The consideration given to transients is, however, of a preliminary nature only; it isnot possible to develop the study of transients in this paper beyond the simple cases of ?ironless? circuits. An interesting and difficult field left open for investigation by mathematical and experimental means is the exploration of transient phenomena in circuits having impedance operators that are not single-valued functions. In Part II, the principal types of apparatus employed in radio-felephony have been considered in as general a way as possible. A bibliography has been attached, where detailed investigations will be found of many matters touched upon but lightly in this paper, because the presentation of matter c- overing so wide a field seemed to exclude extended investigations that had already received very full treatment as self-contained publications.