A general technique of error reduction to improve the accuracy of four-quadrant arctangent approximations through the Möbius transformation is proposed. Simple identities connecting the regular arctangent function and the four-quadrant arctangent function are derived and used to obtain novel four-quadrant arctangent approximations. The new approximations can provide improved accuracy at the expense of a moderate increase in computational cost.

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Persistent URL dx.doi.org/10.1049/iet-spr:20070117
Journal IET Signal Processing
Rajan, S, Wang, S. (S.), & Inkol, R. (R.). (2008). Error reduction technique for four-quadrant arctangent approximations. In IET Signal Processing (Vol. 2, pp. 133–138). doi:10.1049/iet-spr:20070117