Automatic Calibration of Vibration Sensors for Measurement in a Weak Magnetic Field

The paper describes a procedure of automatic calibration and frequency response measurement of a piezoelectric sensor constructed for picking up the vibration of acoustic musical instruments. Unlike piezoelectric vibration accelerometers designed for industrial purposes, this piezo sensor is free of any ferromagnetic material and contains no electronic circuits so it can be used in an environment with a weak stationary magnetic field without risk of electromagnetic interaction. The measured frequency response is subsequently used to design a correction high-pass filter for preprocessing of the picked-up vibration signals prior to the actual spectral analysis.