Real-Time and High-Accuracy Arctangent Computation Using CORDIC and Fast Magnitude Estimation

Electronics

Luca Fanucci¹  Luca Pilato¹  Sergio Saponara¹ 

[1] Dipartimento Ingegneria della Informazione, Università di Pisa, via G. Caruso 16, 56122 Pisa, Italy;

关键词: real-time;    Digital Signal Processing (DSP);    Embedded Systems;    CORDIC (Coordinate Rotation Digital Computer);    ASIC (Application Specific Integrated Circuit);    FPGA (Field Programmable Gate Array);    IP (Intellectual Property);    automotive sensors;   

DOI  :  10.3390/electronics6010022

来源: DOAJ

【 摘 要 】

This paper presents an improved VLSI (Very Large Scale of Integration) architecture for real-time and high-accuracy computation of trigonometric functions with fixed-point arithmetic, particularly arctangent using CORDIC (Coordinate Rotation Digital Computer) and fast magnitude estimation. The standard CORDIC implementation suffers of a loss of accuracy when the magnitude of the input vector becomes small. Using a fast magnitude estimator before running the standard algorithm, a pre-processing magnification is implemented, shifting the input coordinates by a proper factor. The entire architecture does not use a multiplier, it uses only shift and add primitives as the original CORDIC, and it does not change the data path precision of the CORDIC core. A bit-true case study is presented showing a reduction of the maximum phase error from 414 LSB (angle error of 0.6355 rad) to 4 LSB (angle error of 0.0061 rad), with small overheads of complexity and speed. Implementation of the new architecture in 0.18 µm CMOS technology allows for real-time and low-power processing of CORDIC and arctangent, which are key functions in many embedded DSP systems. The proposed macrocell has been verified by integration in a system-on-chip, called SENSASIP (Sensor Application Specific Instruction-set Processor), for position sensor signal processing in automotive measurement applications.

【 授权许可】

Unknown