GB439503A - Improvements in or relating to electron discharge apparatus and circuit arrangements incorporating the same - Google Patents

Abstract

439,503. Valve modulating circuits. MARCONI'S WIRELESS TELEGRAPH CO., Ltd., Electra House, Victoria Embankment, London.-(Assignees of Hansell, C. W. ; Port Jefferson, Long Island, New York, U.S.A.) June 7, 1934, No. 16954. Convention date, July 24, 1933. [Class 40 (v)] For modulating &c. in a wireless circuit a magnetron or like valve is employed subjected to a magnetic field of such intensity that the electrons are forced to move in curved paths which do not reach the anode, whereby the valve acts as a condenser, the capacity of which can be varied by varying the charge on the anode or on a control grid. The Figure shows a transmitting circuit of this type comprising two valves 8, 10 the plate circuits 14 of which are coupled to a transmission line 16 and connected through condensers 28, 30 to the anodes of two valves 24, 26 provided with a solenoid 36 which causes them to act as set forth. Modulating potentials are applied to the anodes of the valves 24, 26 through a transformer 42. The D.C. source 38 which energizes the solenoid 36 also applies a positive potential to the anodes of the valves 20, 22. The filament leads of the valves 8, 10 may be tuned as described in Specifications 417,057 and 431,526. A modification is described in which the modulating potentials are applied to control grids instead of to the anodes. The Specification as open to inspection under Sect. 91 also describes circuits employing valves which are blocked so as to produce a condenser effect by electrostatic instead of electromagnetic fields. This subject-matter does not appear in the Specification as accepted.