method for phasenempfindlichen scanning and phasenempfindlicher detector

摘要

1,024,840. Measuring surface roughness. RANK ORGANISATION Ltd. Feb. 7, 1964 [Feb. 15, 1963], No. 6155/63. Heading G1N. [Also in Division H3]. The feeler point of an instrument is deflected as it passes over a ten surface, thus varying the value of inductances forming two arms of a bridge, whose output is fed to a capacitor the output side of which is connected to earth, (or a fixed voltage), once during part of each cycle of the A.C., by pulses and the average voltage of the capacitor output then measured to indicate the A.C. amplitude and phase sense at the instant of the pulses. The pulses may be derived by phase shifting the A.C. by an R-C network, then squaring it by limiters, and applying it to trigger a transistor monostable circuit whose pulsed output renders conductive the collector/ emitter path of a transistor shunting the capacitor output. The capacitor A.C. output is integrated by a filter.