| 摘要 |
1, 046, 983. Automatic speed control. SEQUENTIAL ELECTRONIC SYSTEMS, Inc. March 19, 1965 [March 23, 1964], No.11716/65. Heading G3R. To provide retroactive speed control of a rotary element down to zero speed a speed and angular position signal is used to effectively amplitude modulate a carrier frequency, and one of the sidebands only is compared with a reference signal in a phase comparator that produces a signal which, upon amplification, drives the rotary element. The arrangement is such that the element follows the reference (which may be produced by a second rotary element) exactly in r.p.m., with a phase displacement sufficient to produce the required power. In Fig. 1 (not shown) an unspecified optical device 12 produces sine and cosine signals of the angular position of an electric motor shaft 13, to facilitate side band selection in a transistor modulator 16 (which is described, Fig. 2, not shown). In alternative arrangements modulation is effected in the optical device, either by energizing the lamp at carrier frequency, or by rotating a grating at a speed corresponding to carrier frequency. |
