This paper presents results of a study of some of the characteristics of the Kinemetrics PDR-1 digital strong-motion accelerograph. The paper gives the results of laboratory tests of the background noise level of the instrument and compares these results with previously reported observations for optical instruments. The determination of displacement from acceleration data is discussed and results of laboratory tests are presented. Certain instrument anomalies are identified, data correction algorithms proposed, and examples given. The paper also presents the results of a comparison of earthquake records obtained from side-by-side digital and optical analog instruments. Finally, some results obtained from a recent Chinese earthquake are discussed.