MULTIRATE ANALOG-DIGITAL SYSTEMS FOR SIGNAL-PROCESSING AND CONVERSION

Systems containing both analog and digital functions have been investi gated with the purpose of realizing mixed-signal integrated circuits w ith higher levels of functionality and integration. In most cases, suc h mixed-signal systems are inherently multirate because of the differe nt sampling rates employed at various stages of the system. The multir ate concepts have been used for traditional applications, such as subb and coding and narrowband filter design. Some unconventional applicati ons of multirate signal processing are also emerging, both for convert ing between analog samples and digital words, and for realizing proces sing functions in an easier and more economical way than would be poss ible using purely digital or analog techniques. This paper reviews fun damental multirate concepts, discusses some recent developments in thi s area of integrated multirate analog-digital systems, and outlines so me possible future directions for research and application.