1、　　等精度数字频率/相位测试仪是电子通信电路测试设计常需要的一种工具。设计的指标包括，测量频率的范围：（0.1Hz-100MHz），测量精度：測频全域不大于百万分之一。具有脉宽测试功能，相位测试功能。系统的组成框图如下所示，TCLK为待测的信号，BCLK为系统的时钟。其主控制结构如图測频原理所示，采用高速的系统时钟BCLK对待测信号时钟TCLK进行计数，然后计算出一个周期的平均值，最后输出高8位数据。-1, and other precision digital frequency/phase Tester is a tool designed electronic communications circuit testing is often needed. Design indicators include measurement frequency range: (0.1Hz-100MHz), measurement accuracy: frequency measurement whole is not greater than one millionth domain. Test function with a pulse width, phase testing. Block diagram of the system is shown below, TCLK is measured signals, BCLK as the system clock. Its main control structure shown in Figure frequency measurement principle, the use of high-speed system clock BCLK clock TCLK treat the measured signal is counted, and then calculate the average value of a cycle, the final output high eight data.