Periodic jitter investigations

Summary form only given. Low amplitude periodic fluctuations are often observed on the body current, output power and the phase of traveling wave tubes (TWTs), as well as other vacuum electron devices (VEDs). These oscillations have been ascribed to various mechanisms and have been termed Helix Jitter, Ticking, and more recently Periodic Jitter. In recent investigations we have verified that the mechanism involves a relaxation oscillation in which ions are trapped and de-trapped in specific locations in the TWT. In this paper we provide further data supporting this mechanism and describe experiments showing the functional dependence of the jitter amplitude and period in TWTs. We will also explore the future demands on signal quality that advanced communication techniques will place on jitter reduction.