CATHODE PULSE MODULATION OF RF TRANSMITTER TUBES

摘要

Beam control pulse modulation in an RF transmitter tube is provided by a solid state switch connected between the cathode power supply and the cathode of the transmitter tube. The beam controlling element is returned to the normal cathode power source such that closing the switch between the cathode and the cathode power source brings the beam controlling element voltage to cathode potential causing beam current to flow, while opening the switch provides a very high equivalent cathode resistance, which self-biases the tube in the cutoff region, eliminating the need for a separate "off" voltage power supply. Off-edge performance may be further improved by providing an off switch connected between the cathode and a collector tap on the cathode power supply, and closing the switch when the on switch is opened to accelerate return of the cathode potential to the cutoff voltage.