A Design of Modulator Power Supply and Pulse Modulator Circuit for a Conventional Traveling Wave Tube Amplifier

TWT is an integral part of a vacuum tube family that can be utilized to amplify the radio frequency (RF) signals in the microwave range. Generally, microwave tubes are used in military radar, electronic warfare, civilian radar, weather forecasting radar, particle accelerators, plasma heating, etc. The contribution of TWT is marked as the microwave receiver as a low-noise radio frequency amplifier and also in wideband communication links and co-axial cables as a repeater amplifier or intermediate amplifier to amplify a low signal. To test a TWT amplifier, some testing circuits are required. In this paper, the authors designed and fabricated two such testing circuits namely the modulator power supply and pulse modulator. The modulator power supply generates three DC output voltages typically +220 V, – 120 V, and +12 V. The operation of the pulse modulator circuit requires a power supply of these typical voltages. The output of the pulse modulator is a pulse train which is obtained by using two 555 timers – one as a monostable and the other as an astable multivibrator. These circuits are primarily simulated on Proteus 8.9 software and then a final hardware design has been done.