Guarded vector voltmeter for AC ratio standard calibration

A new setup for the calibration of the ratio of inductive voltage dividers against a ratio standard is under development at IEN. The setup is based on the direct measurement of voltage vector differences between the device under test and the standard, with a purposely-built vector voltmeter described. The uniqueness of the voltmeter is the extremely high common-mode-rejection-ratio (CMRR), greater than 180 dB at I kHz, obtained with a bootstrapping-guarding technique. The voltmeter is battery-operated has variable gain and a dual-channel synchronous demodulating stage with high harmonic rejection, is operated with a personal computer via an optical-fiber interface.

[1]  Luca Callegaro,et al.  DESIGN NOTE: Optical linking of reference channel for lock-in amplifiers , 1999 .

[2]  Luca Callegaro,et al.  Optical fiber interface for distributed measurement and control in metrology setups: application to current sensing with fA resolution , 2001, IEEE Trans. Instrum. Meas..

[3]  H. Sutcliffe,et al.  Lock-In Amplifiers: Principles and Application , 1984 .

[4]  P. Chang,et al.  An automatic bridge for inductive voltage dividers , 1994 .

[5]  R. Hanke,et al.  An improved straddling method with triaxial guards for the calibration of inductive voltage dividers at 1592 Hz , 1989 .

[6]  Luca Callegaro,et al.  A synchronized two-phase sinewave generator for AC metrology system compensations , 2000, IEEE Trans. Instrum. Meas..

[7]  M. L. Meade.  Lock-in amplifiers : principles and applications , 1983 .

[8]  Luca Callegaro,et al.  Optical fibre interface for distributed measurement and control in metrology setups: application to current sensing with fA resolution , 2000, Proceedings of the 17th IEEE Instrumentation and Measurement Technology Conference [Cat. No. 00CH37066].

[9]  L. Callegaro,et al.  Inductive voltage dividers comparison with a vector voltmeter , 2000, Conference on Precision Electromagnetic Measurements. Conference Digest. CPEM 2000 (Cat. No.00CH37031).

[10]  L. Callegaro,et al.  A synchronized two-phase sinewave generator for AC metrology systems compensations , 1999, IMTC/99. Proceedings of the 16th IEEE Instrumentation and Measurement Technology Conference (Cat. No.99CH36309).

[11]  Matthew E. Briggs,et al.  Measurement of the temperature coefficient of ratio transformers , 1993 .