| 摘要 |
489,325. Valve generating circuits ; thermionic distributers. INTERNATIONAL BUSINESS MACHINES CORPORATION. Nov. 25, 1937, No. 32504. Convention date, Dec. 1, 1936. [Class 40 (v)] A generator for producing short timed pulses comprises a valve the grid bias of which is controlled by an alternating source so that the valve is rendered conductive at intervals and additional means are provided to suppress the signal impulses periodically. The Figure shows a valve 20 in which the grid is normally biassed to zero but the bias is altered bv alternations fed through transformer 24 applied through the full wave rectifier 21, 22 and resistance 26. A condenser 31 is provided so that alternate pulses are insufficient to render the valve conductive so that the valve is rendered conductive once per cycle at the frequency applied to transformer 24. The invention is applicable to a signalling system as described in Specification 469,761 in which a plurality of different phases are derived from an alternating current and applied to a number of generators to give a series of voltage peaks at accurately timed intervals.
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