说明：  Gardner关于位同步算法的经典IEEE文章。
(Abstrucf- Timing adjustment in a digital modem must be performed by interpolation if sampling is not synchronized to the data symbolsT. his paper describest he fundamental equation for interpolation, proposes a method for control, and outlines the signal-processing characteristics appropriate to an interpolator. The material combines a review of previously known topics, presentation of new results, and a tutorial exposition of the subject. A companion paper will treat performance and implerneutation)