Development of charge amplifier calibration system employing substitution method

Takashi Usuda, Akihiro Oota, Hideaki Nozato, Tamio Ishigami, Yasuhiro Nakamura, and Katsuhisa Kudo

Abstract

Charge amplifier is a key device for vibration metrology as well as an accelerometer itself. Reliability of vibration measurement heavily depends on the stability and frequency characteristics of charge amplifier. Especially, phase characteristic of charge amplifier becomes more important as many calibration sectors have adopted Sin-approximation method which enables calibration of accelerometer phase shift.<br /> In this paper, development of charge amplifier calibration system both for amplitude (gain) and phase is reported. The calibration system consists of standard capacitor, inductive voltage divider, injection transformer, and sine signal generator. Because the system does not contain any active device such as voltmeter or A/D converter which requests periodic calibration, it is quite stable and reliable without any maintenance including periodical calibration. The system enables calibration uncertainty of 1.3&middot;10^-3 % in gain and of 6&middot;10^-5 deg. in phase shift at 160 Hz.

Keywords

piezo-electric accelerometer, charge amplifier, calibration, phase-shift, sine approximation method

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IMEKO-TC22-2007-KL-106u.pdf

DOI

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IMEKO TC

TC22 - Vibration Measurement

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