| 摘要 |
563,468. Coilless resonators ; wireless receiving apparatus. LANDMANN, A. April 28, 1942, No. 5719. [Classes 40 (iii) and 40 (v)] A tunable resonator comprises a plate, preferably in the form of a ring 3, with a gap 4 in which a condenser with angularly movable vanes 6 is mounted in order that the circuit formed by the inductance of the plate 3 and the capacity of the condenser may be tuned as desired. The plate 3 is slotted at one or both sides of the gap so as to present a comb-like appearance, and the condenser vanes lie in the slots and are adjustable by rotating the shaft 7. The plate may be of solid metal, or of an insulating material with a metal coating. The material of the plate and the condenser vanes may be chosen so that the resonant frequency remains constant with variations of temperature. The resonator may be employed as the tuned circuit of the local oscillator of a superheterodyne receiver, and may tune from 230 to 310 Mc. /s., the grid and anode of the oscillator valve being connected to opposite sides of the gap 4, or to other suitably chosen points on the ring. |
