Novel CORDIC rotation method for generalized coordinate systems

作者：Kuhlmann Martin; Parhi Keshab K.

来源：Conference Record of the Asilomar Conference on Signals, Systems and Computers, 1999, 2: 1361-1367.

DOI：10.1109/ACSSC.1999.831929

• Coordinate rotation digital computer
• Generalized coordinate systems
• Iterative algorithms

CORDIC (COordinate Rotation DIgital Computer) is an iterative algorithm for the calculation of the rotation of a two-dimensional vector, in linear, circular or hyperbolic coordinate systems, using only add and shift operations. This paper presents a novel algorithm and architecture for the rotation mode in circular and hyperbolic coordinate systems in which the directions of all micro-rotations are pre-computed while maintaining a constant scale factor. Thus, an examination of the sign of the angle after each iteration is no longer required. By using redundant adder, the critical path (without scaling and conversion) of the entire CORDIC architecture only requires (1.5n+2) full-adders (n corresponds to the word-length of the inputs) for rotation mode. This is a speed improvement of about 20% compared to the previously fastest reported rotation mode implementations. Additionally, there is a higher degree of freedom in choosing the pipeline cutsets due to the novel feature of independence of the iterations i and i-1 in the CORDIC rotation. Optional pipelining can lead for example in the rotation mode to an on-line delay of three clock-cycles including scaling and conversion, where every clock cycle corresponds to a delay of twelve full-adders.

• 出版日期1999