Weak–inversion topologies of analog median filters

Alejandro Díaz–Sánchez¹, José Miguel Rocha Pérez¹, Javier Lemus–López¹, Jaime Ramírez–Angulo²*, Germán Ardul Muñoz–Hernández³, Carlos Arturo Gracios–Marín³

¹ INAOE, Luis E. Erro #1. Tonantzintla, Puebla, México. E–mail: adiasan@inaoep.mx,

² Klipsch School of Electrical and Computer Engineering, New Mexico State University, Las Cruces, New Mexico, USA. E–mail:: *jramirez@nmsu.edu

³ Instituto Tecnológico de Puebla Av. Tecnológico 424, Puebla, Puebla, México. E–mail: gmunoz64@hotmail.com

Recibido: 10 de julio de 2009.
Aceptado: 20 de octubre de 2009.

Abstract

Design and implementation of two analog median filter cells are described. The first topology is a differential pairs array, which drain currents are driven into two nodes in a differential fashion. The second topology is based on a wide range OTA, which is used as basic block to maximize the dynamic range. Fabrication parameters for a MOSIS process of 1.6 μm are used. Experimental results of two three–input fabricated prototypes are shown.

Keywords: Non–linear Filters; Median Filters; Weak–Inversion.

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