Patent ID: 8045643

Claim:
A power detection system for detecting output power of quadrature power amplifier circuitry comprising: a) first quadrature downconversion circuitry having a first input coupled to an output of an in-phase amplifier circuit of the quadrature power amplifier circuitry to receive an in-phase output signal and a second input coupled to an output of a quadrature-phase amplifier circuit of the quadrature power amplifier circuitry to receive a quadrature-phase output signal, and adapted to: i) downconvert the in-phase output signal based on a first local oscillator signal to provide a first downconverted signal; and ii) downconvert the quadrature-phase output signal based on the first local oscillator signal to provide a second downconverted signal; b) second quadrature downconversion circuitry having a first input coupled to the output of the in-phase amplifier circuit of the quadrature power amplifier circuitry to receive the in-phase output signal and a second input coupled to the output of the quadrature-phase amplifier circuit of the quadrature power amplifier circuitry to receive the quadrature-phase output signal, and adapted to: i) downconvert the in-phase output signal based on a second local oscillator signal that is essentially −90 degrees out-of-phase with the first local oscillator signal to provide a third downconverted signal; and ii) downconvert the quadrature-phase output signal based on the second local oscillator signal to provide a fourth downconverted signal; and c) circuitry adapted to selectively combine the first, second, third, and fourth downconverted signals to provide at least one of a group consisting of: a signal indicative of forward power and a signal indicative of reverse power.