Method and apparatus for controlling gain of a power amplifier

摘要

A method and apparatus for controlling the gain of a power amplifier wherein the method includes the steps of attenuating, detecting, and comparing. An attenuator (108) attenuates an amplified version of a radio frequency signal to an attenuated level. A single detector (109) alternatively detects the radio frequency signal power level at a power amplifier (101) input and the attenuated version of the amplified radio frequency signal. The detector (109) produces a first and a second signal each having a DC level representing the detected power levels. An operation amplifier configured for closed loop operation compares the DC levels of the first and second signals to produce a control signal (102) for controlling power amplifier (101) gain. Filters (119) and (120) filter the first and second signals before the comparing step.