US Patent 8441320 Cancelation of gain change due to amplifier self-heating

A system includes a power amplifier, a preamplifier, a first temperature sensor, and a bias generator. The power amplifier has a first gain, which is a function of a temperature of the power amplifier. The preamplifier has a second gain, amplifies an input signal, and outputs an amplified signal to the power amplifier. The first temperature sensor senses the temperature and generates a first signal. The bias generator generates a first biasing signal to bias the power amplifier, generates a second biasing signal to bias the preamplifier, and adjusts the second gain by adjusting the second biasing signal based on the first signal. The adjusted second gain compensates a change in the first gain due to the change in the temperature.