Patent ID: 8410850

Claim:
A signal processing apparatus for processing an input signal (x), the signal processing apparatus comprising: an amplifier configured to amplify a processed signal (y′) to obtain an amplified signal (y″); a down-converter configured to multiply a version of the processed signal (y′) with a version of the amplified signal (y″), one of the signal versions being phase shifted, to obtain a first down-converted signal (z 1 , z 1 ′), and to multiply the processed signal (y′) with the amplified signal (y″) to obtain a second down-converted signal (z 2 , z 2 ′); and an adaptive predistorter configured to predistort the input signal (x) according to a predistortion characteristic to obtain the processed signal (y′), the predistorter being further configured to adapt the predistortion characteristic based on the first down-converted signal (z 1 , z 1 ′) and the second down-converted signal (z 2 , z 2 ′).