GB515068A - Improvements in or relating to high frequency oscillators - Google Patents

Abstract

515,068. Electron oscillators. MARCONI'S WIRELESS TELEGRAPH CO., Ltd., and LEVIN, N. May 23, 1938, No. 15342. [Class 39 (i)] An . electronic oscillator comprises means for generating a sharply defined beam of electrons, an apertured electrode system having a plurality of apertures, means for causing the beam to pass in succession through the apertures, and means for refocusing the beam in the plane of each aperture each time it passes through. Preferably, a flat beam is produced by cathode K and control electrode G, accelerating anode AA and focusing electrode S, all provided with the slots aligned with the cathode. The apertures in the subsequent electrodes are correspondingly slotted. In one form a single anode electrode SA, Fig. 2, has a number of apertures through which the beam is threaded by the combined influence of retarding electrodes PP, AP at cathode potential, and of oppositely-directed magnetic fields generated, for example, by oppositely-wound coils shielded from one another by soft iron dividing plates. The magnetic fields may be replaced by electrostatic focusing systems and the potentials of electrodes SA and PP, AP may be interchanged. In another form, separate apertured anodes SA1, SA2, SA3, Fig. 3, are arranged along the beam and electrostatic lens systems IT1, IT2, etc. focus the beam in each aperture. Long or short magnetic focusing coils may also be used ; inthe first case, the anodes are placed at successive foci, while in the second case the rotation of the image is compensated by rotating the apertures or by using two oppositely-wound coils. The electrodes SA1 &c. may be at cathode potential.