Patent GB-530785-A (GB)
Title: Improvements in or relating to electrical oscillating systems
IPC: H03B5/18
Filed: 1939-03-17
Abstract: 530,785. Electron oscillators ; valve amplifying, generating and modulating circuits. LELAND STANFORD JUNIOR UNIVERSITY, BOARD OF TRUSTEES OF. March 17, 1939, No. 8552 Convention date, April 14, 1938. [Classes 39 (i) and 40 (v)] Cascade amplification at frequencies of 100 megacycles or higher is effected by velocity grouping in an electron stream. The electron stream is arranged to deliver energy to an enclosed resonant circuit which enhances the grouping while the process is repeated until the desired amplification is obtained. The resonant circuit may be an internally resonant hollow body as described in Specification 517,264. The Figure shows an electron emitter 1 with an accelerating grid 3 arranged to project an electron beam through resonant hollow bodies 5 ... 8 containing pairs of spaced grids 15 ... 18 which produce the velocity grouping. At the output a plate 32 may be negatively biased so that only electrons of more than average velocity strike it or the plate 32 may be positively biased so that only electrons of less than average velocity fail to strike it. The electrons impinging on the plate produce voltage across resistor 53'while the electrons passing through the aperture in the plate 32 may be observed on fluorescent screen 34. Biased rods 33 or a magnet 35 may be used to concentrate the beam striking the screen 34. The discharge space is sealed to maintain a vacuum while the hollow bodies are adjustably tunable by dipole 36 or coil 37 or by condensers 43, 44 associated with a coil 38 or dipole 39. Gang tuning may be effected by a member having vanes 47 between which standing waves are produced through apertures 40, the member being adjustable through rod 48. Reaction may be used, as by coupling between bodies 7, 8 through loops 57, 58. The bunching of the electrons at the grids may be effected as described in Specification 523,712 alternatively the beam may be deflected as described in Specification 529,771. As shown the signal voltage across resistor 53 is arranged to vary the bias of grid 56 to provide automatic volume control. Manual control of volume is provided by potentiometer 55 and may be used to adjust the effective amount of reaction in addition to the control by adjustment of the loops 57, 58. The resonant hollow bodies 74, 77 coupled by the loops 88, 89 and having associated therewith the electron source 71 comprise an oscillator to which the output of the resonant hollow body 8 is coupled by loops 85, 87. In this way a phase modulated wave may be detected at plate 79 and applied through resistance 95 to a direct current amplifier 96. The output is coupled to the tube 75 through which the electron beam passes and thus changes the frequency of the oscillator. A transmitting arrangement is also described in which the back coupling is effected through a resonant hollow body of a lower frequency but operating at one of its harmonic frequencies to act as a master oscillator. Specification 531,067 also is referred to. The Specification as open to inspection under Sect. 91 comprises also the subject-matter of divided Specifications 530,869, 530,870, 530,871 and 531,067. This subject-matter does not appear in the Specification as accepted.