GB545803A - Improvements in or relating to circuit arrangements for amplifying and separating two or more oscillations - Google Patents

Abstract

545,803. Electron multipliers and circuits therefor. PHILIPS LAMPS, Ltd. (Naamlooze Vennootschap Philips' Gloeilampenfabrieken). June 12, 1940, No. 10263. [A Specification was laid open to inspection under Sect. 91 of the Acts, Dec. 16, 1940.] [Classes 39 (i) and 40 (v) ] A circuit for amplifying and separating two or more oscillations e.g. television signals, uses a secondary emission tube to the control grid of which the signals with, if desired, local oscillations are applied while impedances are included in the anode and auxiliary cathode circuits which have a high value respectively, for each of the oscillations to be amplified or for the corresponding intermediate frequency oscillations. Fig. 1 shows circuits 12, 13 coupling the secondary emitting electrode 5 to the sound output of a television receiver while the anode 6 through coupling 18, 19 applies picture signals to the amplifier 20. In a modification, Fig. 2 (not shown), a frequency changing secondary emitting tube is used, a local oscillator being coupled to the control grid through a small condenser in parallel with the signal input circuit. The electrode having the smaller capacity to the control grid is preferably used as the output for the signal most amplified, preferably the sound signal. Fig. 4 shows a tube construction comprising a cathode 2, control and screen grids 3, 4 respectively having a plate shaped anode 6 arranged outside the path of the electrons travelling to the auxiliary cathode 5. A grid 36 is arranged in front of and parallel to electrode 5 and connected through a condenser to the cathode and given a high positive potential. Screen electrode 38 forms an electrostatic field to determine the electron paths while a screen 39 prevents material vaporized from cathode 2 from reaching electrode 5. The grid electrode 36 may be connected within the tube to the anode 6 through a resistance or choke and to the cathode through a condenser. Specification 527,795 is referred to.