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A new implementation for the logarithmic/exponential function generator

  • Mixed Signal Letter
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Abstract

This paper presents two new approximations for the logarithmic and exponential functions. These approximations require only a square rooter function, a scalar function and a constant. Thus, the realization of these functions in current-mode is simple, straightforward and uses less number of MOSFETs. Simulation results obtained show that the logarithmic function can be obtained with relative root mean square (RRMS) error of 0.0755 over the normalized input range 0.001–1.0 while the exponential function can be obtained with RRMS error of 0.0489 over the normalized input range 0.01–3.0. Much less RRMS errors can be obtained for restricted normalized input values.

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Acknowledgments

The authors acknowledge with thanks the constructive comments of the reviewers which resulted in improved presentation.

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Authors and Affiliations

  1. King Fahd University of Petroleum and Minerals, Box 203, Dhahran, 31261, Saudi Arabia

    Muhammad Taher Abuelma’atti & Noman Ali Tassaduq

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  1. Muhammad Taher Abuelma’atti
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  2. Noman Ali Tassaduq
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Correspondence to Muhammad Taher Abuelma’atti.

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Abuelma’atti, M.T., Tassaduq, N.A. A new implementation for the logarithmic/exponential function generator. Analog Integr Circ Sig Process 83, 75–84 (2015). https://doi.org/10.1007/s10470-015-0505-3

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  • DOI: https://doi.org/10.1007/s10470-015-0505-3

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