A time interval measuring technique with high speed and high resolution

The high resolution time interval measuring technique is widely applied in various areas such as electronic instrument, laser ranging, and physical experiment and so on. The traditional time-to-amplitude conversion-based (TAC) measuring circuit features the high time measuring resolution. However, the measuring speed is low and the measuring result is sensitive to the temperature. This paper firstly analyzes the basic principle of the existing TAC circuit, deduces the mathematical model and indicates the reason of low measuring speed. Based on these, this paper proposes a new TAC circuit based on dual constant-current source (CCS) structure. The error sources that influence the time interval measurement in this TAC circuit based on dual CCS structure are analyzed in detail and the calibration method is presented. The test result shows that the TAC circuit based on dual CCS structure features not only the high measuring accuracy, but also the high measuring speed.