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Calibration of bridge, charge and voltage amplifiers for dynamic measurement applications


Measuring amplifiers are used for transducer output signal conditioning in many dynamic measurement applications. For a traceable measurement, a calibration of all components of the measuring including the conditioning amplifiers is mandatory. In the following, methods for a dynamic calibration of different types of conditioning amplifiers are presented. Measurement uncertainties and calibration results for typical amplifiers are discussed.

Many measurements of mechanical quantities with dynamic signal components are acquired by means of transducers, which need to be connected to signal conditioning amplifiers.  A typical measurement chain with transducer, measuring amplifier and data acquisition electronics (DAQ) is depicted in Fig. 1.
For a traceable measurement with such a set-up, not only the transducer needs to be calibrated, but the measuring amplifier and the DAQ as well.

Figure 1: Measuring chain consisting of a transducer, a measuring amplifier and a data acquisition system.

An overview of dynamic bridge, charge, and voltage amplifier calibration procedures is given in [1] as an open-access publication. Additionally, the calibration of signal conditioners for IEPE transducers (Integrated Electronics PiezoElectric, piezoelectric transducers with integrated electronics) is described. These are the most commonly used amplifiers for the measurement of mechanical quantities.

The calibration results of several bridge, charge, voltage and IEPE amplifiers show characteristic properties of the different amplifier types. Moreover, amplifiers of different type and manufacturer but for the same type of transducer exhibit significant differences in the magnitude and phase of their transfer function, illustrating the importance of calibrations to gain reliable measurement results.



[1] Leonard Klaus, Thomas Bruns and Henrik Volkers, “Calibration of bridge-, charge- and voltage amplifiers for dynamic measurement applications”, Metrologia, Vol. 52(1), S. 72-81 (2015), Opens external link in new windowDOI: 10.1088/0026-1394/52/1/72

Contact persons:

Leonard Klaus, FB 1. 7, AG 1. 73, E-Mail: leonard.klaus(at)ptb.de
Michael Kobusch, FB 1. 7, AG 1. 73, E-Mail: michael.kobusch(at)ptb.de