高精度数字式相位差测量系统设计

Design of a High Precision Digital Phase Difference Measurement System

在测量各种双口网络电路的频率特性时,需要对它们的输入与输出信号之间的相位差进行准确测量,针对采用示波器测量相位差误差较大的问题,提出一种能对信号相位差进行高精度测量的设计方案;系统采用过零鉴相和填充计数的测量原理,利用可编程逻辑器件的高速运算能力对高速脉冲计数,由单片机对工作电路进行协调控制和数据处理显示;同时设计高精度相位差可调的直接数字频率合成信号源对系统进行测试,实际测试结果显示,系统对相位差的测量精度高,最小测量精度可达0.1°,并实现宽频率范围的相位差测量;系统在实际应用中测量结果准确、稳定、可靠。

When measuring frequency characteristics ot the duplex network circuit, the need for accurate measurements ot the phase difference between the input and output signal. In view of the oscilloscope measurement of phase difference exists biggish error problem, can put forward a design scheme for high--precision measurements of the signal phase difference; System adopts zero learning phase and fill the counting measuring principle, using the high speed computing capacity of programmable logic devices for counting high--speed pulse. Through single chip microcomputer coordinate work circuit and processing data to display. At the same time, design of high precision phase difference is adjustable direct digital frequency synthesis source to test system. Test results show that the system has high accuracy of phase difference measurement, and the minimum measurement precision can reach 0. 1°, also realize the wide frequency range of phase difference measurement. In actual application of the system measurement results are accurate, stable and reliable.