Linearizer for use with rf power amplifiers

Abstract

A pre-distortion type linearizer circuit for use in linearizing the performance of power amplifiers such as traveling wave tube and solid state power amplifiers. The linearizer circuit comprises linearizer bridge that includes a phase shifter and a fixed delay in a linear arm, and a distortion generator and an attenuator in a nonlinear arm. The output of the linearizer bridge is coupled through an output amplifier and an output attenuator. The RF output signal from the linearizer circuit is coupled to the power amplifier. A control circuit receives on and off input command signals, and outputs a bilevel telemetry signal that is used as a mode indicator for ground command control. The control circuit adjusts settings of the linearizer bridge, and adjusts gain and attenuation settings of the output amplifier and output attenuator. All circuits of the linearizer circuit may be integrated onto a single alumina substrate, for example. The linearizer bridge circuit may be used with traveling wave tube amplifiers and solid state power amplifiers operating in the S, C, X, Ku, K, Ka, Q, V, or W frequency bands, or any other desired RF frequency band.