AMPLIFIER LINEARIZATION USING A DIGITAL PREDISTORTER WITH FAST ADAPTATION AND LOW MEMORY REQUIREMENTS

Linear modulation methods possess good spectral efficiency. However, their fluctuating envelopes, in conjunction with typically nonlinear power amplifiers, lead to spectral spreading and adjacent channel interference. One remedy is linearization of the amplifier by means of a predistorter. This paper presents and analyzes an adaptive predistorter that is particularly well suited to baseband implementation with digital signal processor (DSP) hardware. In comparison with the most powerful previously published predistorter, it requires four orders of magnitude less memory, reduces convergence time by over three orders of magnitude, eliminates reconvergence time following a channel switch, and eliminates the need for a phase shifter in the feedback path. © 1990, IEEE