| 摘要 |
1,134,060. Phase discriminators. WOODWARD GOVERNER CO. 22 Dec., 1966 [1 Feb., 1966 (2)], No. 57470/66. Heading H3A. [Also in Division G3] The phase relationship of two pulse trains of substantially equal frequency is kept constant by a system in which each pulse in one train 100 triggers a one shot multivibrator 104 whose time constant is approximately half the interval between pulses and which has complementary outputs connected to AND gates 110, 111 to which the second pulse train 101 is also applied; thus, each pulse in the second train causes an output on one or the other of the AND gates according to whether it occurs in the first or second half of the period of the first train of pulses, and these outputs are arranged to advance or retard the phase of the second pulse train. The pulses are produced by generators 90, 94 driven by master and slave aircraft engines, one pulse per revolution, and connection is effected by a stepping servomotor Wi, Wd which adjusts the length of a throttle cable. The servomotor is also controlled by signals from the system for keeping the frequency relationship constant described in Specification 1,134,059 (see Division G3). As shown, the system includes an arrangement for creating a dead band of width " D " around the " in phase " condition which comprises a second one shot multivibrator 120 of time constant D whose output inhibits further AND gates 122, 124 so that adjusting signals are blocked. A delay of ¢D is interposed at 121 to centralize this dead band around the desired phase position. |
