GB599700A - Improvements in or relating to tuning control means for cavity resonators adapted tobe excited by electromagnetic waves - Google Patents

Abstract

599,700. Modulating apparatus cavity resonators. SPERRY GYROSCOPE CO., Inc. May 26, 1943, No. 6009/45. Convention date, May 27, 1942. Divided out of 599,672. [Classes 40 (iii) and 40 (v)] Tuning of a cavity resonator is modulated by a rotatable tuning element projecting within the cavity and adapted during part of its rotation to provide periodic variation of the resonator frequency and during another part to maintain the frequency constant. Amplitude modulation is thus provided of the highfrequency energy present in the cavity. As shown in Fig. 2, two such resonators are provided in a single structure, each comprising a cylindrical cavity 16, 17 and an axial stem 18, 19 integral with one of the end watts. The other end walls are slotted to receive rotary discs 8, 9 both on the same driving-Shaft 7, Fig. 6, and both having sinusoidal or other teeth 51 round one half of the periphery and a smooth rim on the other half. One set of teeth is of different pitch from the other and when one set is within the resonator, the other is outside. High-frequency energy is fed to the resonators by a concentric line 2 and loops 28, 29, and output energy is taken from each resonator to a corresponding aerial by pick-up loops 30, 31 and lines 10, 13. The whole may constitute an equi-signal beacon as described in Specification 599,672. As the points of the teeth, or the smooth part of the rim, approach closely to the stems 18, 19, the corresponding resonator is put out of tune with the highfrequency energy, and radiation is reduced or annulled. Preliminary tuning of the resonators may be effected by rotatable members 44, Fig. 3, adjustable by a screw-driver placed in a slot 45, and provided with a flat tongue 43, or a loop, projecting into the resonator cavity. Specification 523,712 also is referred to.