Research On High Precision TDC For Measuring The Continuous Pulses

The system of time-to-digital conversion is based on the Field Programmable Gate Array (FPGA)(1), compared with the TDC system existing now, the innovation of this design is can measure the width of the continue pulses. This system is designed on the Spartan-6 platform of the Xinlinx company. There are three modules included in this design, the coarse count measurement modules, exact measurement modules and the manage of the measured data module. The key and the difficult of this design are in the exact measurement module, it is measured by using the carry chain which is consisted by the slices, the slices in the Configurable Logic Blocks(CLBs), which are the main logic resources for implementing sequential as well as combinational circuits, and each CLB element contains a pair of slices. The measurement accuracy of this design is within 100ps, and the measurement dynamic range is flexibility, it is based on the bits of the register used in the design, the register used in this design is 32 bits,so the dynamic range can up to about four seconds.