GB473330A - Improvements in or relating to carrier signalling systems - Google Patents

Abstract

473,330. Modulating systems. TELEPHONE MANUFACTURING CO., Ltd., and PADDLE, L. H. April 6, 1936, No. 10131. [Classes 40 (iii) and 40 (v)] In a carrier wave modulator comprising a pair of diode or contact rectifiers connected in series opposition across one of the sources of current which is directly connected to the output, the other current source is connected from the junction of the rectifiers to a point in the winding of a transformer connected across the rectifiers. The carrier and modulation, which are interchangeable, are fed from terminals A, B, C, D, to transformers T, T1, Fig. 1, the secondary of T1 being connected from the mid point of the rectifiers R1, R2 to the centre tap of the secondary of T, or the primary of the output transformer, Fig. 2 (not shown). Various modifications are shown in which the transformers are replaced by potentiometer arrangements. A loss of modulation occurring at high frequencies due to the capacity of the rectifiers may be corrected. by a suitable resistance, inductance, condenser combination, Fig. 5 (not shown). The Provisional Specification describes an arrangement employing two pairs R1, R2; R3, R4 of opposed rectifiers, Fig. 7, similarly connected, with one of the currents applied between the junction points. In a modification, Fig. 8 (not shown), the rectifiers are in opposition, and the system is not reversible, the modulation being applied between the junction points. Specification 417,251 is referred to.