GB542780A - High-frequency energy transfer circuits - Google Patents

Abstract

542,780. Valve circuits. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. July 29, 1940, No. 12311. Convention date, July 28, 1939. [Classes 40 (iii) and 40 (v)] Methods are described for connecting valve circuits to concentric line resonators in such a way that the effect of the electromagnetic fields on the connecting leads cancels out, and the required leads are of the minimum length. Fig. 1 shows the invention applied to an oscillator comprising a pair of push-pull connected valves 7, 8 controlled by a concentric resonant line formed by an inner conductor 1 one quarter wave length long connected to an outer conductor 2 by an end plate 3. The grid of valve 7 is connected to the inner surface of conductor 2 by a lead 5 passing through conductor 1 while the grid of valve 8 is connected to the outer surface of conductor 1 by lead 6 which passes through conductor 2. By this arrangement the voltages induced in the leads will be equal and opposite. The anode voltage is applied to the mid-point of the tuned output circuit 9, while grid bias is applied through a choke 11 connected to conductor 2. Fig. 3a shows an arrangement for connecting a push-pull transmitter 16 by means of concentric lines 2Z to a transmission line Z connected to two branch lines z/2 The inner conductors of lines 2Z are connected to the inner and outer conductors of Z each passing through the other conductor at a distance of from the end. The outers are oppositely connected to the conductors of Z. At the upper end the outer conductor of the branches is connected to Z by a quarter wavelength sleeve 21. In this way the impedances are matched. A similar arrangement is described for connecting a push-pull transmitter to a quarter wavelength radiator, Fig. 3, not shown. Fig. 4 shows an oscillator T mounted inside a resonant concentric line in which the conductors 11, 21 are connected together by an earthed plate 31 and are capacitatively coupled by an adjustable plate 25. The grid and filament leads are capacitatively coupled to the outer conductor while the leads pass through for making the direct current connections. The anode is capacitatively coupled to the inner conductor 1<SP>1</SP>. This arrangement reduces the reactance of the leads to a minimum. An oscillator is also described using a resonator in the form of a hollow cylinder which may also be in the shape of an hour-glass or sphere.