GB571483A - Improved system for registering a train of positive and negative half cycles of an alternating current - Google Patents

Abstract

571,483. Selective signalling. WESTERN ELECTRIC CO., Inc. Sept. 10, 1943, No. 14875.. Convention date, Aug. 6, 1942. [Class 40 (i)] [Also in Group XL] The members of a chain of gas-filled discharge tubes respond to the successive half-cycles of an incoming signal. As shown, the incoming signal is amplified at L and passed direct to a transformer POS and through a phasereversing tube INV to a transformer NEG. The effect of this is that while the current is rising (second half of a negative half-cycle and first half of a positive half-cycle) an impulse tending to cause break-down is applied to the primary (left-hand) electrodes of all the odd-numbered tubes and an impulse tending to prevent breakdown is applied to the primary electrodes of the even-numbered tubes. The converse effect is produced while the current is falling. The rising part of the first positive half-cycle. breaks down tube 1, which has a normal bias over resistance A1, and the resulting discharge current biases tube 2 so that it responds to the falling parts of the half-cycle and the subsequent negative half-cycle. Break-down of tube 2 similarly biases tube 3 which responds when the current rises again and so on. If five complete cycles are received, tube 11 is operated by the second half of the last negative half-cycle. The tubes 2 to 11 may have signalling devices connected to their cathodes to indicate how many half-cycles have been received.