GB600205A - Improvements in or relating to thermionic valve generating circuits - Google Patents

Abstract

600,205. Pulse circuits. HARRISON, A. April 18, 1945, No. 9763. [Class 40 (vi)] In a Miller integrating circuit, a conductive impedance is included in the cathode circuit and means are provided for feeding an external voltage across this impedance, so that the injected waveform is superimposed on the linear fall in anode voltage which occurs through normal operation of the Miller circuit. In Fig. 2, the anode and control grids are connected to H.T. positive through loads 2 and 3 and the suppressor grid is normally biassed beyond cutoff, so that current through the valve may be released by a positive pulse on the suppressor grid. The resulting fall in anode voltage is fed to the control grid through condenser 4, which tends to reduce anode current and the potential of the grid rises as condenser 4 discharges, thus tending to increase anode current. A steady state is reached where the control grid maintains a substantially steady potential, while a substantially linear fall in anode voltage occurs. A proof is given that the injection of a waveform voltage to the cathode across impedance 7 produces an equal variation in the voltage at the anode, so that the final voltage of the anode is the algebraic sum of the cathode applied waveform and the linear fall voltage. The final waveform may be used to select any one of the input oscillations by arranging for it to be applied to a switching device (such as a separate valve biassed to a voltage below cutoff) which will operate when the voltage drops to the predetermined value. Specification 580,891 is referred to.