GB581968A - Improvements in or relating to the generation of electrical impulses - Google Patents

Abstract

581,968. Valve generating circuits. STANDARD TELEPHONES & CABLES, Ltd., LEVY, M. M., and WEAVER, L. E. April 4, 1941, No. 4506. [Class 40 (v)] An arrangement for producing shortened electrical pulses from original pulses comprises a thermionic valve and a delay network whose input terminals are connected in series with the cathode circuit of the valve and whose output terminals are left unconnected, the original pulses being applied to the control grid of the valve and the shortened pulses being taken from the plate circuit. In the form shown in Fig. 7, a time delay network 1 is connected across the terminals x1, x2 of an impedance Z0 in the cathode circuit of a valve 2, to the grid of which an impulse a of steep front is applied. This causes a corresponding impulse to be applied to network 1 which is reflected back as an impulse b which is of the same sign and slightly delayed since terminals y1, y2 are open-circuited. The a and b impulses are combined at x1, x2 and the output taken at Z1, Z2 through a blocking condenser 10 comprises an impulse c of very steep front and of very short duration. Fig. 8 shows an arrangement in which a valve 2 has in its anode circuit an anti-resonant circuit 11, 12 critically damped by an impedance Z0 and delay network 1 with its output terminals y1, y2 shortcircuited. A second delay network 1<1> with open-circuited output terminals is connected across an impedance Z<1>0 in the cathode lead. The circuit without the delay networks would produce steep-fronted pulses from a squaretoppod input a1. Network 11 increases the steepness of the pulse by effecting a sharp cutoff of anode current as in Fig. 7, while network 1 further narrows the pulse by combination with a delayed reflected pulse of reversed sign. Specifications 514,271 and 528,310 are referred to.