Patent ID: 6194964
Filing Date: 2001-02-27
Classification: H03F

Abstract:
A predistorter of a high frequency amplifier, comprising:an automatic gain control circuit for controlling an overall gain of said high frequency amplifier so that there is no change in the overall gain of said high frequency amplifier when an output signal is changed as a result of comparing an input signal to the output signal;a variable attenuator being controlled by said automatic gain control circuit so that there is no change in an overall gain of said high frequency amplifier; thereby minimizing the change of gain of a combined signal; anda linearizer; said linearizer comprising:a signal divider for dividing the input signal into a main-path signal and a sub-path signal;a phase shifter for delaying the phase of said main-path signal;a harmonic generator for generating harmonic signals derived from said sub-path signal;a variable attenuator for attenuating an output signal of said harmonic generator;a variable phase amplifier for amplifying a phase of an output signal of said first variable attenuator;a combiner for combining an output signal of said variable phase amplifier with an output signal of said phase shifter; anda main amplifier for amplifying said combined signal.