Quantitative Relations in Detector Circuits (A Discussion on Mr. Armstrong's Paper on "A Study of Heterodyne Amplification by the Electron Relay.")

In the case of a simple receiving system it is shown that even with a "perfect" rectifier, as defined, there is more high-frequency energy in the detector circuit than is associated with the rectified current. Also, with a "perfect" rectifier it is shown that the heterodyne method gives just four times the energy in the response as the "breaking up" methods give, irrespective of the amplitude of the local E. M. F. "Approximate" rectifiers are defined. General formulas are derived for calculating the rectified current and the received radio frequency current flowing in a simple detector circuit of known characteristic; also, general formulas for calculating the beat frequency current and the received radio frequency current in the case of the heterodyne, when the local E. M. F. is larger compared with that received. From these formulas, and from the definition of an "approximate" rectifier, it is shown that the energy in the response must always be less than the energy in the signal.