A high-speed CORDIC algorithm and architecture for DSP applications

Abstract

This paper presents a novel CORDIC algorithm and architecture for the rotation and vectoring mode in circular coordinate systems in which the directions of all micro-rotations are precomputed while maintaining a constant scale factor. Thus, an examination of the sign of the angle or y-remainder after each iteration is no longer required. By using Most-Significant Digit (MSD) first adder/multiplier, the critical path of the entire CORDIC architecture only requires (1.5 n+2) and (1.5 n+10) full-adders (n corresponds to the word-length of the inputs) for rotation and vectoring modes, respectively. This is a speed improvement of about 30% compared to the previously fastest reported shared rotation and vectoring mode implementations. Additionally, there is a higher degree of freedom in choosing the pipeline cutsets due to the novel independence of iteration i and i-1 in the CORDIC rotation. Optional pipelining can lead for example to an on-line delay of three clock-cycles where every clock cycles corresponds to a delay of twelve full-adders.