RNS-BASED ENHANCEMENTS FOR DIRECT DIGITAL FREQUENCY-SYNTHESIS

Two synthesizer designs are presented which exemplify the advantages of the use of the Residue Number System in Direct Digital Frequency Synthesis. The Frequency Agile Direct Synthesizer (FADS) exhibits a frequency switching latency which is reduced by more than a third below that of traditional, binary number system-based designs. The Reduced Area Direct Synthesizer (RADS) has a chip area which is reduced by more than 40% below that of the traditional designs. The area reduction is due to the decomposition of the sine ROM into several small look-up tables accessed in parallel. The latency reduction is due to the shortening of the carry paths in the Phase Accumulator.