A Method of Obtaining a Linear Time Axis for a Cathode Ray Oscillograph

Abstract

The usefulness of a cathode ray oscillograph tube of the type of the Western Electric No. 224-B is enhanced by any circuit that will provide a linear time axis. A number of methods of accomplishing this result have been described from time to time. One method used in the Bell Telephone Laboratories employs a hot-cathode three-element gas-filled tube in the usual ``sweep'' circuit. This method possesses advantages in reproducibility, ease of control and synchronization. A brief description of the tube is given together with a simple analysis of the behavior of the circuit. Methods of coupling the sweep circuit to the oscillograph tube, of synchronizing the sweep frequency and of improving the linearity are discussed. A complete portable laboratory oscillograph outfit is shown as an illustration of one form that the device may assume. This set is for use within the audible frequency range.