GB454059A - Improvements in or relating to electric discharge tube oscillation generators - Google Patents

Abstract

454,059. Valve generating circuits. COMPAGNIE GENERALE DE TELEGRAPHIE SANS FIL, 79, Boulevard Haussmann, Paris. Nov. 21, 1935, No. 32292. Convention date, Nov. 24, 1934. [Class 40 (v)] In a valve oscillation generator of the kind in which frequency is stabilized by the insertion of suitable impedances in the grid and plate circuits, as described in Specification 431,455, the plate circuit is shunted by circuits designed to select particular harmonics which are amplified and rectified to provide an automatic control bias for an auxiliary valve electrode, thereby maintaining constant the amplitude ratio of the harmonics and the fundamental. The grid circuit may include a reactance network designed to give resonance at the fundamental and harmonic frequencies. As shown, the back-coupled valve 8 has a tuned circuit 9 connected to the plate through a coil 10. The plate is connected to earth through a rejector circuit 1 for blocking the fundamental, in series with a number of branched circuits 2, 3 designed to accept the various harmonics. Voltage from one of these is applied to the grid of an amplifier 4 feeding a rectifier 5 having a load resistance 6. Voltage varying with the amplitude of the chosen harmonic is tapped from the resistance 6 and applied to an auxiliary grid 7, which may be screened, of the valve 8. In order to prevent generation of harmonic voltages in the grid circuit, due to grid current, the grid coil 11 is connected to the grid through a reactance network comprising a condenser 12 shunted by a number of inductance-capacity branches 13, 14. These are designed to give series resonance in the grid circuit at the fundamental and harmonic frequencies. The Specification also discusses the frequency stabilization of an oscillator in which the tuned circuit is inductively coupled both to the plate and to the grid circuit, Fig. 4 (not shown).