Power amplifier with PDM modulated valve - has pre-emphasis circuit connected to control grid making amplitude of short pulses smaller than that of longer pulses

摘要

The power amplifier contains a valve with a screen grid and is designed for max. efficiency. The signal being amplified is PDM modulated by pulses applied to the valve's control grid. A pre-emphasis circuit is connected to the valve's control grid to make the amplitude of short pulses smaller than that of longer pulses. The pre-emphasis circuit is arranged so that the valve operates in the region below its cathode's saturation current and the control and screen grid currents do not exceed the max. allowed even for the longest pulses.