| 摘要 |
<p>701,686. Coincidence circuits. STANDARD TELEPHONES & CABLES, Ltd. Jan. 13, 1950 [May 23, 1949], No. 919/50. Class 40 (6). [Also in Group XXXVIII] In an electric signalling system (see Group XXXVIII), use is made of a coincidence circuit in which pulses are applied to a point PC via leads B1, B2, W) in parallel, one lead B1 including a resistance Rh and each (including one) of the other including a rectifier or diode Rc. When pulses simultaneously occur on all the rectifier-containing leads B2, W the pulse on the resistance-containing lead B1, if it then occurs, is effective at the point PC. In all other circumstances at least one of the rectifiers is conductive and the voltage drop in the resistance Rh reduces the potential at the point PC below the pulse potential. Tube Va will not fire to less than the pulse potential. Specifications 636,700 and 701,739 are referred to.</p> |
