A High-Frequency Sweep Circuit

A linear high-frequency sweep circuit for the cathode ray oscillograph is described. It employs a linearly charged condenser periodically discharged by a hard tube, the grid of which is biased past cut-off except for short periods when it is driven positive by an auxiliary oscillator. The frequency of this oscillator is made commensurable with that of the unknown wave form to be investigated. The circuit is particularly adaptable for high frequencies, photographs of alternating voltages of frequencies up to twelve megacycles being shown.