Review of methods for time interval measurements with picosecond resolution

This paper is a review of methods and techniques used for precise measurement of time intervals (TIs) or precise conversion of TIs to digital data. The following methods are described: the counter method and averaging, time stretching, time-to-amplitude conversion followed by analogue-to-digital conversion, the Vernier method, conversion utilizing tapped delay lines, and interpolation methods. Special attention has been paid to converters utilizing integrated delay lines for digital conversion of TIs, including designs with phase-locked loop and delay-locked loop circuits. This review is illustrated by design examples and contains a comprehensive list of references.