Aliased wide band performance monitor for adjusting predistortion and vector modulator control parameters of RF amplifier

摘要

A digital signal processor-resident RF power amplifier performance monitor generates and updates signals for controlling each of an adaptive predistortion unit and a vector modulator of a preamplification signal processing loop, and a vector modulator of a feed- forward error extraction and reinjection loop. A performance monitoring routine subjects monitored aliased data to a window function and determines the spectrum of the data. The spectral data is applied to a sensitivity mask, which masks the data in accordance with a carrier-- intermodulation distortion function associated with the operation of the amplifier. The output of the mask is processed to derive a measure of intermodulation distortion power. The intermodulation distortion power is subjected to an error minimization operator, such as a perturbational gradient search, that adjusts each of the control signals for the components of the loops, in such a manner as to maximally cancel intermodulation distortion products.