| 摘要 |
592,397. Electron oscillators ; automatic frequency control. WESTERN ELECTRIC CO., Inc. Nov. 23, 1943, No. 19589. Convention date, April 11, 1941. [Classes 39 (i) and 40 (v)] [Also in Group XXXV] In a velocity modulated oscillator of the reflex type, the gap is defined by two grids 34, 37, Fig. 1, which are dished in a direction away from the cathode, and the reflecting electrode 38 is dished in the same sense. As shown, the resonator consists of coaxial metal cylinders 40, 41 connected to discs 33, 35 sealed through the wall of the envelope 10 and provided with apertures closed by the mesh discs 34, 37. The resonator is tuned by an adjustable plug 43 and screw 44. The electron gun consists of an indirectly heated cathode comprising a cylinder 14 closed by a flat electron emissive disc 15, a focusing electrode 17 in the form of a sleeve 17, and an accelerating electrode in the form of a sleeve 19 with the end closed by a mesh disc 20 preferably dished towards the cathode ; all the parts are mounted as a unitary structure on a metal base 21 which is supported on rigid wires at the stem 11 of the envelope; In a modification, Fig. 4'(not shown), the envelope is a metal cylinder and the resonator is entirely enblosed therein, the discs forming the gap having a sliding fit in the cylinder and being clamped in position by sliding sleeves : tuning of the resonator is by a coaxial line of adjustable length. The oscillator may be coupled to a device for stabilizing its frequency as shown in Fig. 3. This consists of a resonator 70 tuned to the desired frequency by a screw 71, and coupled to the oscillator 10 by a coaxial line 75 and loops 75a, 76a, 76b. The lengths of the leads to the loops are such that the voltage at the loop 75a is 90 degrees out of phase with that at the loops 76a, 76b. The latter are connected by rectifiers 72a, 72b across a resistance 73, which in turn is connected across the input terminals of a D.C. amplifier 74. Variations in the frequency of the oscillator produces a variation in the output of the rectifier which alters the potential of the reflecting electrode 38 and restores the frequency. |
