GB636877A - Improvements in or relating to electronic valves of the velocity modulated type operating on very short waves - Google Patents

Abstract

636,877. Velocity-modulated tubes. COMPAGNIE GENERALE DE TELEGRAPHIE SANS FIL. May 13, 1946, No. 14452. Convention date, Sept. 19, 1942. [Class 39 (i)] A high-frequency electron discharge device of the velocity modulated type comprises a buncher including resonant circuits tuned to a frequency f/2 and to harmonics thereof, for producing a non-sinusoidal modulating field acting transversely of the beam, a drift space, and a catcher including a resonant circuit tuned to a frequency f. It is stated that the beam is velocity modulated at double the frequency of the control frequency owing to the longitudinal action of the boundary fields of the transverse control field, the length of the control field being such as to correspond to an odd number of half cycles of the control frequency. As shown, the buncher comprises two pairs of electrodes B1, B2. The quarterwave line L1 connected to electrodes B1, resonates at a frequency f/2, and the quarterwave line L2 connected to electrodes B2 resonates at a frequency f. The catcher field is bounded by grids G1, G2 which together with elements L<1>3, L"3 form a transmission line circuit resonant at frequency f. Feedback is provided between the resonant circuit L"3 and the resonant circuit L2. The Specification as open to inspection under Sect. 91 comprises also arrangements in which the buncher modulating field is wholly longitudinal, and comprises a number of harmonic sinusoidal fields in superposition or juxtaposition. In one arrangement the buncher and catcher each comprises two rhumbatrons, one resonant at frequency f and the other resonant at frequency 2f. As shown in Fig. 6 (Cancelled), the beam is deflected in the drift space by the electrode H. In another arrangement the velocity-modulated tube is of the reflex type. This subject-matter does not appear in the Specification as accepted.