CORDIC architectures with parallel compensation of the scale factor

Abstract

The compensation of scale factor imposes signifcant computation overhead on the CORDIC algorithm. In this paper we will propose two algorithms and architectures in order to perform the compensation of the scale factor in parallel with the computation of the CORDIC iterations. This way it is not necessary to carly out the final multiplication or add scaling iterations in order to achieve the compensation. With the architectures we propose the dependence on n of the compensation of the scale factor disappears, and this considerably reduces the latency of the system. The architectures developed are optimized solutions for the different operating modes of the CORDIC both in conventional and in redundant arithmetic. 0 (rotation mode) or it is taken to the coordinate axis (vectoring mode). The algorithm is based on the decomposition of the rotation angle into known elementary angles. The basic iteration or microrotation is: By means of the CORDIC algorithm, a vector of coordinates (x,y) is rotated an angle * This work was supported by the Ministq of Education and Science (CICYT) of Spain under project TIC-92-0942 258 1063-6862195 $4.00 0 1995 IEEE Session 8: Arithmetic I1x(i+l)=x(i) + o,2'y(i) y(i+l)=y(i)o,2'x(i) z(i+l)=z(i)o,tg-'2-'

P-CORDIC: A Precomputation Based Rotation CORDIC Algorithm

“…In every iteration a significant amount of time is used to examine the most significant bit in case of a binary architecture or the most significant three digits of a redundant architecture to predict the sign of z(i) and hence the rotation direction σ i . In comparison to the CORDIC implementations with constant scale factor, other implementations use a minimally redundant radix-4 or an even higher radix number representation [12,13,14]. These architectures make use of a wider range of σ i .…”

Architecture implementation of an improved decimal CORDIC method

“…Several methods to avoid performing the final product by K m -1 and carry out the scaling compensation in parallel with each of the iterations have been proposed [17]- [21].…”

A Fast Architecture for Radix 10 Coordinates Rotation

“…Several techniques to avoid performing the final product by K m -1 and carry out the compensation of the scaling in parallel with each iteration have been proposed [21]- [23].…”