Digit on-line large radix CORDIC rotator

Abstract

Many applications figure the evaluation of rotations at high speeds. However there is a trade-off between the chip area and the latency. In this paper we develop a digit on-line pipelined array architecture based on the radix-4 CORDIC algorithm in rotation mode. The radix-4 CORDIC algorithm halves the number of microrotations with respect the traditionally radix-2 algorithm with the drawback of a non-constant scale factor. Seeking a good compromise between silicon area and latency we have used digit on-line processing. This way the data inputs the processor in blocks of bits (digits) in MSD-first mode of processing. We have used redundant carry-save arithmetic to allow carry-free additions and on-line processing. The designed processor demonstrates to have a better performance than previous digit on-line architectures.