Improving Architectures of Binary Signed-Digit CORDIC With Generic/Specific Initial Angles

Abstract

Coordinate rotation digital computer (CORDIC) is widely used in digital signal processing (DSP) to calculate functions. One of the elegant ways to accelerate CORDIC is employment of the redundant binary signed-digit (BSD) number systems, so-called BSD-CORDIC. This paper aims to achieve efficient BSD-CORDIC structures for generic/specific initial angles. First, three generic BSD-CORDIC algorithms are optimized by exploiting a suitable data gating technique as well as appropriate BSD encodings. The synthesis results demonstrate that for generic CORDIC, the proposed BSD-CORDIC schemes enhance the existing ones in terms of speed, power consumption, and area overhead. Second, the look-ahead BSD-CORDIC is proposed as a special case of BSD-CORDIC with specific initial angles. We also show that for the applications like fast Fourier transform (FFT), where the initial angles are known in advance, the proposed look-ahead BSD-CORDIC with the posibit-negabit encoding, as our best presenting structure, noticeably improves speed, power consumption, and area overhead.