GB663830A - Improvements in or relating to velocity-modulation systems and discharge tubes therefore - Google Patents

Abstract

663,830. Velocity-modulated tubes. PHILIPS ELECTRICAL, Ltd. Aug. 11, 1947 [Aug. 14, 1946], No. 22224/47. Addition to 645,937. Class 39 (i). In a velocity modulation device for generating or amplifying ultrahigh - frequency oscillations in which the beam is velocity - modulated by a control electrode system, the velocity modulation is converted into density modulation by a brake field electrode which causes the beam to retraverse the system, in which the beam is then again reversed by a second brake field electrode so as to traverse the system a third time, and in which a double grid surrounding an equipotential space is arranged between the control electrode system and the brake field electrode more remote from the cathode, as set forth in the parent Specification, the control electrode system comprises four parallel electrodes 6, 4, 5, 7, so connected and arranged as to form a single electric resonator supporting standing waves. In the drawing, 3 and 9 are the brake field electrodes, and electrode 3 also serves to form the beam. The electrodes 6, 4; 5, 7 form two quarter-wave resonators and are shorted at one edge by a plate, Fig. 1 (not shown), so as to form a half-wave Lecher system with a voltage node at the plate; electrodes 6, 5 and 4, 7 are connected by wires 14, 15 so that 6, 4; 5, 7 oscillate in anti-phase. Electrode 10 carrying the double grid and brake field electrode 3 are joined by plates 11, 12 so as to form a rectangular box preventing the escape of energy from the oscillating system. The output is taken from two strips forming part of a Lecher line sealed through the envelope and capacitatively coupled to electrodes 4, 5. The Specification as open to inspection under Sect. 91 refers to the provision of a magnetic focusing field. The electrodes of the control system are formed as strips. This subjectmatter does not appear in the Specification as accepted.