Power Amplifier Pre-Distortion Signal Generator Using an Analog Baseband Envelope Feedback Loop

摘要

Presented are methods and apparatuses for maintaining a substantially constant gain and reducing gain compression (AM-AM distortion) of a power amplifier based on a pre-distortion signal generated from an analog, baseband envelope feedback loop.

主权项

1. A system comprising:
a baseband signal generator configured to generate a baseband signal; a mixer for upconverting the baseband signal to a radio signal; a power amplifier configured to amplify the radio signal; and a pre-distortion circuit configured to bias the power amplifier and including:
an envelope extractor for extracting an envelope of the baseband signal;a first attenuator coupled to an output of the envelope extractor;a first power amplifier unit cell coupled to an output of the first attenuator;a second power amplifier unit cell coupled to an output of the envelope extractor;a second attenuator coupled to an output of the second power amplifier unit cell;a comparator block coupled to the first power amplifier unit cell and to the second attenuator for generating an error signal associated with a difference between an output of the first power amplifier unit cell and an output of the second attenuator; and a biasing element coupled to an output of the comparator block which biases the power amplifier using the error signal.