Experimental Investigation About the Effect of Voltage Ripple of the Power Supply on the Performance of High Power Electron Tubes

In this paper, the effect of voltage ripple of the cathode power supply on the phase noise of high power electron tubes is experimentally studied. The conducted experiments are carried out on a traveling wave tube. A high voltage cathode power supply with voltage ripple adjusting capability is used to apply the various levels of voltage ripple to the studied tube. The designed power supply is able to provide a wide range of voltage ripple from the high values to very low values. Therefore, it is possible to study the behaviour of the tube at the cathode voltage with a very low ripple. The output power spectrum of the tube is presented to show the level of the tube phase noise. The experiments show a high dependency between the level of phase noise of the tube and the cathode voltage ripple. This conclusion is valid for even very low values of the voltage ripple. Thus, it is concluded that the tube provides a very small phase noise if the cathode voltage ripple is kept at a very low level.