| 摘要 |
<p>The invention provides an apparatus for, and a method of, counting the revolutions of a rotating component (1). The apparatus comprises means (5) for generating a signal (10) having features which correspond to marks (3) on the component (1) and means (13) for utilising the signal to determine the number of marks (3). In one embodiment the means (13) for utilising comprises means for matching features in the signal to determine two features which are generated by the same mark and means for calculating the number of marks to be one more than the number of features between the two features. Conveniently the features are peaks or troughs in the variation of the magnitude of the signal with time.</p> |
