基于TDC的无死区频率测量技术研究

在精密时频测控领域中,高分辨率、无死区的时间间隔和频率测量非常关键,而时间数字转换器(Timeto Digital Converter,TDC)是时间频率测量的常用手段.该文研制了基于ACAM公司生产的时间数字转换芯片TDC-GP21和Altera公司FPGA芯片EP4CE6E22C8N的时间频率测量设备,实现了高分辨...

Research on Dead-time Free Frequency Measurement Technology Based on TDC

In the fields requiring precise time and frequency measurement and control, high-precision, dead-time free time interval and frequency measurements are highly demanded. TDC (Time to Digital Converter) is commonly adopted in time and frequency measurement. In this paper, a self-developed multi-module time-interval measurement system is built based on the time digital conversion chip TDC-GP21 from ACAM company and the Cyclone IV FPGA chip EP4CE6E22C8N from Altera Company. For each time-interval measurement module, a time-interval measurement resolution as small as 13 ps is achieved. By further duplex operating two such time-interval measurement modules, a dead-time free frequency measurement is realized, the time and frequency measurement system involves three groups, each of which has 3 TDC chips. By averaging the measurement results of three TDC chips in each group, a frequency instability reaches $ 1.1times {10}^{-11} $@ 1s and $ 5.6times {10}^{-15} $@10000 s. This result shows that this self-developed apparatus approaches the performance of the commercial K+K FXE frequency counter. Due to its advantages of small size, no calibration and low cost, this apparatus can be widely used in applications that require high-precision time interval and precise frequency measurements.