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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Referencias

[1]. I. Pitas and A. Venetsanopoulos, Nonlinear Digital Filters: Principles and Applications (Kluwer Academic Publishers, Boston, 1990).         [ Links ]

[2]. D. Richards, VLSI Median Filters, IEEE Trans. on Acoustic, Speech and Signal Proc, 38, 2, (1990).         [ Links ]

[3]. M. Karaman, L. Onural and A. Atalar, in: VLSI Signal Processing III, Eds. R.W. Brodersen and H.S. Moscowitz (IEEE Press, New York, 1988).         [ Links ]

[4]. P. H. Dietz and L.R. Carley, An Analog Technique for Finding the Median, in Proc. IEEE Custom Int. Circ. Conf., (1993).         [ Links ]

[5]. I. Opris and G. Kovacs, "Improved Analogue Median Filter", Elect. Letters, 30, 4 (1994).         [ Links ]

[6]. A. Diaz–Sanchez, J. Ramirez–Angulo, A. Lopez and E. Sanchez–Sinencio, A Fully Parallel Analog Median Filter," IEEE Trans. on Circ. and Syst. II, (2004).         [ Links ]

[7]. P. Furth and A. Andreou, Transconductors in Subthreshold MOS, 29^th Conf. on Inf. Sci. and Syst., (Baltimore, 1993).         [ Links ]

[8]. A.G. Andreou and K. Boahen, in: Analog VLSI Signal and Information Processing, Eds. M. Ismail and T. Feiz, (McGraw–Hill, 1994).         [ Links ]

[9]. Y. Tsividis, Operation and Modeling of the MOS Transistor, (McGraw–Hill International Editions, Singapore, 1999).         [ Links ]

[10]. C. Mead, Analog VLSI and Neural Systems, (Addison–Wesley, Reading, MA, 1989).         [ Links ]