GB379831A - Improvements in or relating to carrier-wave signalling over electric supply wires - Google Patents

Abstract

379,831. Wired wireless systems ; multiplex signalling. SIEMENS & HALSKE AKT.-GES., Siemensstadt, Berlin. Aug. 7, No. 22428, Convention date, Aug. 8, 1930. [Class 40 (v).] Telegraphic signals of different note-frequencies, and distant-control impulses up to 400 cycles, are all superposed on the speech currents and modulated on a common carrier-wave used for intercommunication purposes over the supply wires connecting say electric power stations. In transmission the audio-frequency currents are amplified at low frequency, whilst on the receiving side they are amplified at high frequency. A high-frequency valve-generator S, Fig. 2, is modulated (a) by direct-current telegraph impulses through a filter Gl; (b) by interrupted tone signals through a filter Tg applied tc the input of an amplifier V1; and (c) by speech currents from a subscribers microphore on the line T. Incoming signals pass from the line F to an amplifier E and are rectified at V2. The output from the rectifier is separated into (a) direct-current impulses which pans through to a relay GlR; (b) tone telegraph signals which pass through a filter Sp1 to a recorder Tg; and (c) speech currents which pass through a chain filter K1 to the subscribers receiver on the line T.