Table of Contents
ISRN Biomedical Engineering
Volume 2013, Article ID 750290, 7 pages
Research Article

Companding Realizations of the Nonlinear Energy Operator

Physics Department, Electronics Laboratory, University of Patras, 26504 Rio Patras, Greece

Received 30 April 2013; Accepted 30 May 2013

Academic Editors: V. Krajca and U. Pliquett

Copyright © 2013 Andreas-Christos Demartinos et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Realizations of the nonlinear energy operator (NEO), using the concept of companding filtering, are introduced and compared in this work. For this purpose, the Log-Domain and Sinh-Domain filtering techniques have been followed. Both topologies are constructed from differentiator and multiplier blocks which have been realized through the utilization of nonlinear transconductor cells. Both of the proposed topologies offer the capability of ultra-low voltage operation, thanks to the employment of MOS transistors in the weak inversion. Considering a single power supply voltage of 0.5 V, the behavior of the proposed NEO realizations has been simulated using the Analog Design Environment of the Cadence software and the design kit of the TSMC 130 nm process. Comparison results show that the Sinh-Domain realization offers a more power efficient design than that offered by the Log-Domain realization.