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