Eamon Nash, Analog Devices

This article will begin by describing a typical Zero-IF or direct-conversion transmitter along with providing a brief introduction to digital modulation. The imperfections introduced by the modulator will be examined with particular focus on the effect of temperature and frequency changes. In-Factory and In-Field algorithms that can reduce the effect of these modulator imperfections will also be discussed. Particular focus will be placed on the efficacy of In-Factory “set-and-forget” algorithms.