Patent ID: 7755425

Claim:
A predistorter 200 for reducing frequency memory effects in a RF power amplifier, which predistorter has a predistorter input signal (x) and an output signal (v g ) wherein said predistorter includes first means ( 1 ) for generating a first signal component (î d ), which is an estimate of a drain current of said amplifier, which means ( 1 ) for generating said first signal component comprises a linear filter; second means ( 8 ) for generating a second signal component (v 8 ) as a function of said first signal component (î d ) and at least one first gain function (h 10 , h 11 , h 12 , ƒ 1 ), which at least one first gain function (h 10 , h 11 , h 12 , ƒ 1 ) represents the sensitivity of the power amplifier and is a function of the amplitude of a selected time-delayed version (v 3 ) of said first signal component (î d ); third means ( 9 ) for generating a third signal component (v 9 ) as a function of a conjugate of said first signal component (î d ) and at least one second gain function (h 20 , h 21 , h 22 , ƒ 2 ), which at least one second gain function (h 20 , h 21 , h 22 , ƒ 2 ) represents the sensitivity of the power amplifier and is a function of the amplitude of said selected time-delayed version (v 3 ) of said first signal component (î d ); and fourth means ( 7 ) for combining at least said second signal component (v 8 ) and said third signal component (v 9 ) to form said output signal (v g ).