GB592121A - Oscillation generator - Google Patents

Abstract

592,121. Inductive output tubes. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. July 27, 1944, No. 14404. Convention date, April' 24, 1941. [Class 39 (i)] 'In.a high-frequency electron discharge device of the inductive output type comprising means for producing a focused beam of electrons including a cathode 2, Fig. 1, control electrode 4 and an electron permeable anode 5 located at one end of an evacuated envelope, a collector electrode 6 located at the other end of the envelope and a cavity resonator 20 having a gap ab located between the electron permeable anode 5 and the collector 6, an oscillatory circuit 9 is coupled between the cathode 2 and the anode 5 and a second oscillatory circuit 12 is coupled between the control electrode 4 and the anode 5 to cause the electrons to pass across the resonator gap ab in periodically occurring groups so as to excit the resonator 20. The resonator 20 is tuned to a frequency equal to or a harmonic multiple of the frequency of passage of the electron groups across the resonator gap ab. The oscillatory circuits 9, 12 and the anode 5 are grounded so that the system formed by the electrodes 2, 4 and 5 acts as a self-excited triode oscillator. The circuits 9, 12 are tuned respectively to below and above the frequency at which the triode section as a whole oscillates, and are preferably constructed of concentric or parallel wire transmission line sections whose length is adjustable for tuning. The electron beam is focused by magnetic lenses ab, cd formed between spaced iron sleeves 21, 22 and 23, the magnetic path being completed by a strip of iron 18 and an iron core 19 excited by a solenoid 24. The copper resonator 20 is preferably cylindrical, toroidal, or, as shown, of hour glass cross-section ; the distance of the arcuate wall of the resonator 20 from the axis of the envelope at the resonator gap ab is approximately one-quarter of the resonant wavelength of the resonator. Means (not shown) may be provided for varying the width of the gap ab. A second accelerating electrode 5<1> is inserted between the resonator gap ab and the collector 6 and is connected to ground as shown. A suppressor electrode 7 is provided.