Improved Methods for Digital Measurement of Torsional Vibration

An overview of analog and digital torsional vibration measurement methods is presented. Significant sources of digital measurement error are discussed in detail. Methods to minimize measurement errors are explored. A method to use multi-bit A/D data acquisition of a magnetic pickup signal to accurately measure tooth passing frequency with low sample rates is proposed. A frequency domain correction window is proposed which improves the frequency response of the standard digital demodulation technique. The proposed improvements enable accurate torsional vibration measurement with inexpensive A/D data acquisition equipment.