| 摘要 |
625,067. Radio signalling ; radio receiving systems ; diplex radio signalling. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN. Nov. 22, 1946, No. 34730. Convention date, June 12, 1943. [Class 40 (v)] In a signal receiver for carrier-wave telephony systems in which the carrier is suppressed during speech, but is used for transmitting the call signals, the call-signal oscillations Vp are applied in the same sense to the rectifiers of each of two oppositely connected pairs 4, Fig. 3, of biassed rectifiers while an auxiliary oscillation Vq of constant amplitude is applied in the opposite sense. By this arrangement the call signal oscillations are converted into output oscillations of reduced frequency and constant amplitude for ensuring reliable operation of the call relay. Instead of providing negative bias for the rectifiers, as shown in Fig. 3, the bias may be dependent upon the current flowing through the call relay 11, Fig. 6, the bias being derived from a resistance 15, 16 included in the anode circuit of an amplifying valve 10 following a detector 9 and filter 8. |
