Development and study of an automatic AC bridge for impedance measurement

Author

Dutta, Mita ; Rakshit, Anjan ; Bhattacharyya, S.N.

Author_Institution

Dept. of Electr. Eng., Jadavpur Univ., Calcutta, India

Volume

50

Issue

5

fYear

2001

fDate

10/1/2001 12:00:00 AM

Firstpage

1048

Lastpage

1052

Abstract

An automatic ac bridge method employing the principle of balancing by means of a stochastic gradient search algorithm is presented. Among the various gradient search techniques, the Widrow-Hoff least mean square (LMS) technique has been chosen as it involves a low computational burden. The LMS algorithm has been used by the authors for the operation of an ac bridge operating with continuous variables. The relevant operation has been verified by simulation; it can also measure negative impedance. A relation has been established between parameters to be used in the LMS algorithm for discrete and continuous versions of the bridge. The balance convergence time for a relatively simple form of the LMS bridge, namely, the R-R type bridge, has been theoretically established and experimentally verified both by simulation and real-time implementation. The frequency response of the LMS algorithm has also been determined

Keywords

bridge instruments; computerised instrumentation; convergence of numerical methods; digital simulation; electric impedance measurement; frequency response; interference suppression; least mean squares methods; stochastic processes; LMS algorithm; NVidrow-Hoff least mean square technique; R-R bridge; ac bridge method; balance convergence time; balancing; convegence factor; frequency response; negative impedance; real-time implementation; simulation; stochastic gradient search algorithm; time varying impedance; Bridge circuits; Computational modeling; Convergence; Frequency estimation; Frequency response; Impedance measurement; Least squares approximation; Stochastic processes; Time measurement; Voltage;

fLanguage

English

Journal_Title

Instrumentation and Measurement, IEEE Transactions on

Publisher

ieee

ISSN

0018-9456

Type

jour

DOI

10.1109/19.963156

Filename

963156