Nonlinear Phase Shift in Traveling-Wave Tubes as Applied to Multiple Access Communications Satellites

A modern communications satellite typically amplifies many frequency-modulated radio-frequency carriers in a single common amplifier. The nonlinear phase versus input power behavior of traveling-wave tubes (TWT) and its impact on intermodulation noise and intelligible crosstalk is treated. A theoretical model is presented, which allows calculation of the multicarrier performance of the TWT, and an experimental verification of the model is given.