Patent attributes
A system for linearizing RF amplifiers employing baseband predistortion techniques provides additive or multiplicative predistortion of the quadrature (I/Q) input signal. The predistorter uses a discrete-time polynomial kernel to model the inverse transfer characteristic of the amplifier, providing separate and simultaneous compensation for nonlinear static distortion, linear dynamic distortion and nonlinear dynamic effects including reactive electrical memory effects. A predistortion controller monitors and compares the amplifier output with the quadrature input signal to compute estimates of the residual output distortion of the amplifier. Output distortion estimates are used to adaptively compute the predistorter parameter values in response to changes in the amplifier's operating conditions. The computed values are used in the predistorter. The predistortion system of the invention may provide broadband linearization of RF amplification circuits including, but not limited to, dynamic load modulation amplifiers.
