標題: Fast CORDIC algorithm based on a new recoding scheme for rotation angles and variable scale factors
作者: Chih, JC
Chen, SG
電子工程學系及電子研究所
Department of Electronics Engineering and Institute of Electronics
關鍵字: CORDIC algorithm;variable scale factor;table lookup method;residual angle and scale factor recoding
公開日期: 1-一月-2003
摘要: This work proposes a new rotation mode CORDIC algorithm, which considerably reduces the iteration number. It is achieved by combining several design techniques. Particularly, a new table-lookup recoding scheme for rotation angles and variable scale factors is developed to reduce the iteration numbers for rotation and scale factor compensation. By addressing the MSB parts of the residual rotation angles to a lookup table, two micro rotation angles are retrieved that in combination best matches the MSB parts. We also combine the leading-one bit detection operations for residual rotation angles, to skip unnecessary rotations. The resulting problems of variable scale factors are then solved by our previous fast decomposition and compensation algorithm (C.C. Li and S. G. Chen, in Proceedings of 1996 IEEE International Symposium Circuits and Systems, May 1996, Atlanta, USA, pp. 264-267; C.C. Li and S.G. Chen, in Proceedings of 1997 IEEE International Conference on Acoustic, Speech and Signal Processing, Munich, 1997, Germany, pp. 639-642). To further reduce the iteration number of scale factor compensation, we again apply the mentioned residual recoding technique and the leading-one bit detection scheme to the fast variable scale factor algorithm. Those techniques collectively reduce the iteration number significantly. Simulations show that in average the new design needs only 9.78 iterations to generate results with 22-bit accuracy, including all the iterations for rotations and scale factor compensations. Statistically, the total iteration number is less than n/2 for results with n-bit accuracy. The introduced extra table size is of the same order of magnitude as that for the angle set {tan(-1) 2(-i), i = 0, 1,..., n}, required by general CORDIC algorithms. The new recoding scheme can be applied to other elementary function such as division and square-root functions.
URI: http://dx.doi.org/10.1023/A:1021185600444
http://hdl.handle.net/11536/28215
ISSN: 0922-5773
DOI: 10.1023/A:1021185600444
期刊: JOURNAL OF VLSI SIGNAL PROCESSING SYSTEMS FOR SIGNAL IMAGE AND VIDEO TECHNOLOGY
Volume: 33
Issue: 1-2
起始頁: 19
結束頁: 29
顯示於類別:期刊論文


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