Weighted median filters with sigma-delta modulation encoding

Digital decimation filters play a fundamental role in oversampled sigma-delta A/D decoders. In this paper, we first show that weighted median (WM) filtering of a demodulated sequence (at the Nyquist rate) can be implemented concurrently in the A/D decoder. Through a simple modification of the binary...

Full description

Saved in:

Bibliographic Details
Published in:	IEEE transactions on signal processing Vol. 48; no. 2; pp. 489 - 498
Main Authors:	Arce, G.R., Grabowski, N.A., Gallagher, N.C.
Format:	Journal Article
Language:	English
Published:	New York, NY IEEE 01-02-2000 Institute of Electrical and Electronics Engineers The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subjects:	Applied sciences Circuits Converters Decoders Decoding Delta-sigma modulation Discontinuity Encoding Exact sciences and technology Filtering Filters Filtration Frequency Information, signal and communications theory Modulation Multilevel Quantization Sampling methods Signal and communications theory Signal processing Signal to noise ratio Signal, noise Telecommunications and information theory Waveform Experimental result System performance AD conversion Signal processing Delta modulation Sigma modulation Median filter Modeling Implementation Non linear filtering
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	Digital decimation filters play a fundamental role in oversampled sigma-delta A/D decoders. In this paper, we first show that weighted median (WM) filtering of a demodulated sequence (at the Nyquist rate) can be implemented concurrently in the A/D decoder. Through a simple modification of the binary time-series outputted by the A/D modulator, the sequence obtained after the sigma-delta modulation (SDM) decoder is shown to be equivalent to WM filtering the multilevel sequence at the Nyquist rate. Second, we show that WM filters can be used for SDM decimation filters and that these filters are readily implemented in the SDM binary domain. A very promising characteristic of SDM converters equipped with WM decimating filters is that sharp discontinuities (edges) can be preserved and acquired. Thus, the bandlimited constraint imposed on the input signals can be relaxed making SDM more attractive to A/D conversion of signals containing sharp transitions. The proposed signal processing algorithms, in essence, combine A/D sigma-delta converters and WM filters into a single programmable system.
Bibliography:	ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23
ISSN:	1053-587X 1941-0476
DOI:	10.1109/78.823975