Method for improving the accuracy in the determination of a waveform center of a waveform signal

Abstract

Prior to performing a centroid calculation on a waveform signal that is discretely sampled at a limited number of sample points, the last sample point (V , A ) is eliminated if the magnitude of the amplitude at the first sample point (A ) is greater than the last sample point (A ), and the difference in magnitude between the first and last sample points (A −A ) is greater than the difference in magnitude between the second to last sample point and the first sample point (A −A ). The first sample point (V , A ) is eliminated prior to the centroid calculation if the magnitude of the amplitude at the last sample point (A ) is greater than the first sample point (A ), and the difference in magnitude between the last and first sample points (A −A ) is greater than the difference in magnitude between the second sample point and the last sample point (A −A ). In a second embodiment of the invention, a first centroid calculation is performed using a set of samples in which one side of the waveform signal has the lowest amplitude value sample. Sample values on the side of the waveform initially having the lowest amplitude value are then eliminated until the opposing side of the waveform has the lowest amplitude value sample. A second centroid calculation is then performed and the two centroid calculations are averaged together to arrive at an average centroid calculation. In a third embodiment of the invention, the amplitude components of the waveform sample values are normalized to the lowest amplitude value sample point and a first centroid calculation is performed on the normalized waveform signal. Next, the waveform is normalized to the lowest amplitude value sample point on the other side of the waveform signal and a second centroid calculation is performed. The two centroid calculations are then averaged to provide an averaged normalized centroid calculation.