Analog signal processing in an AC electromagnetic flowmeter

Author

Polo, J. ; Pallas-Areny, R. ; Martin-Vide, J.

Author_Institution

Dept. Tecnologia, Univ. Pompeu Fabra, Barcelona, Spain

Volume

3

fYear

2001

fDate

2001

Firstpage

2136

Abstract

AC electromagnetic flowmeters yield a low-frequency signal whose amplitude is proportional to the average fluid velocity. Typically, the signal amplitude can be below 1 mV and suffers a strong interference from the coils that create the driving magnetic field. This paper provides a novel circuit design to amplify and demodulate the voltage picked up by the electrodes and to minimize interference. The amplifier includes a fully differential front end. The demodulation consists of synchronous rectification and sampling with zero-order hold followed by low-pass filtering. The result is a 0.25 mV/(m/s)/mT voltage insensitive to dc level shifts

Keywords

analogue processing circuits; demodulation; electric sensing devices; flowmeters; signal processing; signal sampling; 1 mV; AC electromagnetic flowmeter; analog signal processing; average fluid velocity; below 1 mV; circuit design; coils; differential front end; driving magnetic field; interference; low-frequency signal; low-pass filtering; synchronous rectification; zero-order hold; Circuit synthesis; Coils; Demodulation; Differential amplifiers; Electrodes; Interference; Magnetic fields; Sampling methods; Signal processing; Voltage;

fLanguage

English

Publisher

ieee

Conference_Titel

Instrumentation and Measurement Technology Conference, 2001. IMTC 2001. Proceedings of the 18th IEEE

Conference_Location

Budapest

ISSN

1091-5281

Print_ISBN

0-7803-6646-8

Type

conf

DOI

10.1109/IMTC.2001.929573

Filename

929573