Patent ID: 7689182

Claim:
A polar modulation system comprising: a polar modulator adapted to receive data to be transmitted and to provide a phase signal and an amplitude signal of a polar modulated signal; a power amplifier adapted to provide an amplified polar modulated signal and comprising a transistor, which comprises: a base providing a base input, which is adapted to receive the phase signal; a collector providing a supply input, which is adapted to receive the amplitude signal; and an emitter, the transistor having a base-emitter voltage drop that is dependent on the operating temperature of the power amplifier; and bias circuitry adapted to provide a bias signal, which is a function of an operating temperature of the power amplifier, to the base input, wherein the bias signal compensates for the base-emitter voltage drop as the operating temperature of the power amplifier changes and varies with the operating temperature of the power amplifier to maintain a consistent operating point as the operating temperature of the power amplifier changes.