Research And Application Of The Precise Time Interval Measurement Techniques Based On The TDCs And FPGA

Time is the characterization of matter’s continuous movement, and the time interval is an accurate measurement of physical events’sequence. The precision time interval measurement has a wide range of applications in many fields, such as scientific research, digital communications, power transmission, satellite navigation, time synchronization, and so on. It’s of great significance to the national economy and national defense by developing the time interval measurement technique. So this technology has been paid much attention and been researched extensively by the developed countries. As a result, numerous types of time interval measurement methods were invented.With the traction of the demand from the fields which are critical in the national economy and the national defense construction, such as navigation and positioning, mobile communications, smart grid and so on, many institutes in China carried out a plenty of researches around the time interval measurement. Due to the necessity of the precision time interval measurement in the time synchronization system, we also carried out the relevant researches. A precision time interval measuring method based on TDCs and FPGA was proposed, which was successfully applied in a time interval measuring instruments and a time synchronization system.The article sections are organized as follow. Firstly, the article reviews the concept of time interval measurement technique. A variety of time interval measurement methods are introduced by comparing their advantages and disadvantages. Then a precision time interval measurement principle based on TDC and FPGA circuit is described in detail, including the accuracy and range of this measurement method. Finally, by applying this method, two systems are developed. One is a time interval measurement instrument; the other is a time synchronization system. Experimental results show that TDC and FPGA approach not only can achieve very high resolution (65ps), but also can have a wide measurement range (1s). The time synchronization stability of the time synchronization system can be as low as7.2ns. As a result, the low-cost, high-precision time synchronization information can be easily obtained by the time synchronization system.