Device for the production of the same angular position of a rotating radar antenna on the one hand and the straightening a device for the transmission of the antennas direction to the evaluating part of the radar - plant, on the other hand,

摘要

890,819. Radar. DECCA RECORD CO. Ltd. Dec. 20, 1960 [Dec. 28, 1959], No. 44031/59. Class 40(7). [Also in Group XL(b)] In a remote position control apparatus, a rotatable follower element, e.g. the deflection coils or the resolver of a P.P.I. radar apparatus, is driven by a motor synchronously with a continuously rotating member, e.g. a radar aerial, and switches are associated with the member and the follower which each produce a pulse during each revolution, the pulses feeding a bi-stable circuit which controls the engagement of a clutch in the drive from the motor to the follower, thereby to make the angular position of the follower correspond exactly to the position of the rotating member. As applied to a radar apparatus having rotating deflection coils, the coil holder 21 is required to be kept in synchronism with the aerial 12 driven by a motor 16. A generator 19 driven from the aerial shafting feeds a synchronous motor 20 which, via a clutch, drives the coil holder 21. A switch 22, which may be the heading or azimuth bearing marker switch, is closed once in each revolution of the aerial to provide a voltage 'reset' pulse at the grid of valve 25 part of a bi-stable circuit circuit. A second switch 27 mounted on the coil holder 21 may be adjustable there-about and is also closed once per revolution to give at the grid of valve 25 a 'set' pulse which has a shorter duration than that of the 'reset' pulse, this being ensured by the differentiating network 29, 70. In operation, if a 'set' pulse occurs valve 25 conducts and the clutch is disengaged so that the coil holder stops rotating. The clutch, Fig. 3 (not shown) is disengaged by the passage of anode current in the coil 55. Upon the closure of switch 22, the 'reset' pulse causes the clutch to be reengaged. The 'set' pulse being shorter than the 'reset' pulse the clutch is not disengaged if the two pulses are in substantial coincidence.