| 摘要 |
1,156,050. Selective signalling. ZELLWEGER Ltd. 2 Nov., 1966 [30 Nov., 1965], No. 49197/66. Heading G4H. In a circuit designed to respond to a particular sequence of pulses superimposed upon a power cable, a silicon controlled rectifier 63, Fig. 3, is set conductive by a "start" pulse, a contact 43 is controlled by a synchronous motor 60, also turned on by the "start" pulse, so as to close with contacts 44, 46 in a sequence corresponding to the particular sequence of pulses to which the circuit is designed to respond, a contact 34 is controlled by the received pulses, and the arrangement is such that at the first mis-match between the incoming pulses and the alternations of contact 43, a short-circuit path is established across the S.C.R. 63 which thus reverts to its off condition. Thus the conductive condition of the S.C.R. at the end of the sequence, which is sampled by a contact 50, is indicative of whether a "correct" signal has, or has not, been received. Contact 43, and various other timing contacts, is constituted by a brushsensed printed circuit pattern (Figs. 4, 5, not shown) driven, for one revolution, by the synchronous motor. |
