| 摘要 |
851,007. Radio direction-finding. STANDARD TELEPHONES & CABLES Ltd. Feb. 20, 1959 [Feb. 22, 1958], No. 5936/59. Class 40(7). [Also in Group XXXVI] The invention relates to a cyclic switching arrangement for a circular array of individual aerials arranged to couple the aerials to a transmitter or receiver in a given order so as to simulate the effect produced by a moving aerial for beacon or direction-finding purposes. It is particularly concerned with arrangements in which an apparent oscillatory motion is superposed on a rotational movement. In a directionfinder embodiment utilizing twelve aerials 1 arranged regularly round a circle each aerial is connected to a corresponding segment 3 on a stator shown schematically at 2. Aligned with each segment 3 and spaced therefrom on the stator are further segments 4 all of which are coupled together and connected to receiver 17 by line 5. Coupling between segments 3 and associated segments 4 is achieved capacitively by segments 7 arranged on a rotor 6. A generator 8, 9 and ring-type goniometer 12, 13 fed therefrom over slip rings 11 provide reference outputs over lines 15 and 16 to the direction indicator 19. In this embodiment a simple switching oscillation consisting of three single steps forward alternating with two single steps backwards is used and the regular spacing and width of the stator segments 3 and 4 is as indicated in Fig. 3a. Fig. 3b shows the spacings and arrangement of the five double segments 7 on the rotor. Each pair of rotor segments is coupled by a small inductor 22 which forms a series resonant circuit at the midfrequency of the operating band with the rotorstator segment capacitances. Wide band matching is obtained in known manner by providing also a parallel resonant circuit consisting of the inductor 24 resonating with the earth capacitance of the switch elements. Instead of capacitive coupling inductive coupling may be used and a way in which this can be done utilizing ferro-magnetic elements on a rotor coupling pairs of coils on a stator is described with reference to Fig. 2 (not shown). It is also stated to be possible to use variable reactances in each aerial feed and to control these by voltages generated photo-electrically by light directed to a slotted stator and rotor co-operating in a way analagous to that described above. The Specification describes how the width and spacings of the segments are related to the number of aerials and the switching sequence required. |
