中文摘要：

通过对数字式频率特性测试仪原理的分析和研究,提出以DDS AD9958芯片作信号源与相位检测计数脉冲,实现等精度相位测量功能的方案。系统硬件由DDS AD9958芯片及其外围电路和相位检测电路组成,通过对AD9958芯片的通道寄存器和控制字寄存器的软件进行设置,使芯片输出两路频率成360倍关系的扫频信号,实现等精度测量。利用软件控制芯片实现等精度测量,降低了频率变化产生的精度误差,实现方法简单方便。

英文摘要：

Based on analysing and studying the principles of digital frequency characteristics tester,the scheme of realizing the phase detection function with equal accuracy is put forward by taking DDS AD9958 chip as the signal source and phase detection counting pulse.The hardware is composed of DDS AD9958 chip,peripheral circuits and phase detection circuit.The equal accuracy of phase measurement is achieved by setting the channel register and control word register of AD9958 chip with the software to allow the chip to output two sweep signals whose frequency relationship is that one is 360 times to another.The phase detection with equal accuracy is realized based on chips controlled by the software.The precision errors caused by the frequency change are reduced.The method is simple and convenient.