CASCADE AMPLIFIER LINEARIZATION IN A RADIO FREQUENCY SYSTEM

摘要

A linearization circuit reduces intermodulation distortion in a cascade amplifier that includes a first stage and a second stage. The linearization circuit receives a first signal that includes a first frequency and a second frequency and generates a difference signal having a frequency approximately equal to the difference of the first frequency and the second frequency, generates an envelope signal based at least in part on a power level of the first signal, and adjusts a magnitude of the difference signal based on the envelope signal. When the cascade amplifier receives the first signal at an input terminal, the first stage receives the adjusted signal, and the second stage does not receive the adjusted signal, intermodulation between the adjusted signal and the first signal cancels at least a portion of the intermodulation between the first frequency and the second frequency from the output of the cascade amplifier.

主权项

1. A method to improve amplifier linearity for a cascade amplifier, the method comprising:
receiving at an input terminal of a cascade amplifier a first signal including first signal components having a first frequency and second signal components having a second frequency, the cascade amplifier including at least a first amplifier circuit and a second amplifier circuit configured in series; generating a second signal having a third frequency approximately equal to the difference between the first frequency and the second frequency; adjusting an amplitude of the second signal based at least in part on a power level of the first signal; and applying the second signal to the first amplifier circuit and not to the second amplifier circuit to cancel at least a portion of intermodulation components in a third signal being output from the cascade amplifier.