GB590495A - Electric wave impulse generators - Google Patents

Abstract

590,495. Generating H.F. oscillations; pulse modulation. STANDARD TELEPHONES & CABLES, Ltd. Nov. 22,1944, No. 23260. Convention date, Feb. 25, 1942. [Class 40 (v)] Short electric wave-impulses of high energy are generated by arranging a D.C. circuit to be interrupted electro-mechanically under the control of signal currents so as to shock-excite a substantially closed hollow resonator from which the generated wave impulses are derived. As shown, the interrupter comprises a vibrating rod 32, mounted in a vessel 30 evacuated or filled with an inert gas, and operated by an electromagnet 13 to open normally closed contacts 31, 36, in a circuit energized by a D.C. source 14 and including a tank circuit formed by a hollow resonator 25 which at each opening of the switch is shock excited. Since the switch contacts interrupt substantially without arcing, very high power, wave trains are induced in the tank, circuit and may be radiated from antenna 18 or transmitted to any other load circuit. Preferably, the magnet 13 is energized by time-modulated pulses derived, e.g. as described in Specification 511,222, from a time modulator 22 supplied with signals from source 21 for modulating impulses from generator 20. The rod 32 is, in this case, damped so that it is capable of following the time modulation. The load antenna 18 is coupled by a coaxial line 28 and loop 27. The enclosed switch 30 is attached directly to a portion of the walls of the resonant chamber so that the latter forms in part an envelope for the enclosed switch. The upper contact of the vibrating switch member is substantially in line with one of the walls of chamber 25 to which the fixed switch contact 36 is directly connected. Alternatively, contact 36 may be made integral with the chamber 25. The battery 14 is preferably connected to the chamber 25 at a plurality of points over lines 24 to secure adequate current distribution. In a modification, Fig. 3 (not shown), the glass switch envelope 30, instead of being sealed to a metal member forming part of chamber 25 as in Fig. 2, merely extends into the chamber.