GB604202A - Improvements in and relating to cavity oscillators - Google Patents

Abstract

604,202. Electron oscillators. PHILCO RADIO & TELEVISION CORPORATION. April 10, 1945, No. 8924. Convention date, Nov. 27, 1943. [Class 39 (i)] A cavity-type oscillator comprises a resonant cavity, a vacuum tube mounted therein and including a grid electrode, an opening in the wall of said cavity through which extends a conductor connected to the grid and a hollow conductive member in spaced relation with said conductor and connected to the cavity wall. This connection eliminates spurious oscillations in both grid-pulsed and anode-pulsed cavity oscillators. Fig. 3 shows how the grid cylinder 6 and grid ring 15 are connected to the axial conductor 22 which is supported in an opening in the cavity wall &c. by a polystyrene sleeve 24 and a conductive sleeve 21, the capacitance providing a lowimpedance byepass for the generated carrier frequency, but not for the pulse frequency. The pulse signal is derived from a transformer and applied to the grid via the conductor 22, the tube being of the lighthouse type, with a tuning member and a R.F. choke mounted on the plate pillar. In a second method of gridpulsing the tube, the axial conductor passes through a quarter-wave R.F. choke which is supported by a dielectric sleeve in the wall opening, the outermost end of the choke being an integral multiple of half wavelengths from the grid cylinder. In plate-pulsed tubes where the grid is connected to the outer cylinder of the casing, the connector 33 (Fig. 5) of the grid is connected through a resistance 34 to the wall 2, and passes through a dielectric sleeve and a conducting sleeve 32. Its action is stated to be that of a grid leak, providing a D.C. path from grid to cathode. Specification 591,874 is referred to.