基于FPGA和自动增益控制技术的宽带数字频率计

摘要

The paper discussed the design of a new frequency measurement system based on FPGA and automatic gain con -trol technology(AGC)with high accuracy.The AGC circuit can adjust the gain automatically according to the amplitude of input signals,so as to stabilize the amplitude of output signal around a certain value.Through the method of equal frequency measure-ment,elements such as frequency,phase-difference and duty factor can be measured at the same time.The measuring error of sine wave blow 100 MHz can be controlled in 10-4.The system uses NIOS Ⅱkernel to drive peripherals such as keyboard,LCD,blue-tooth etc,which all make the system have certain practical significance.%设计了一种基于FPGA和自动增益控制技术(AGC)的新型高精度频率测量系统.AGC电路会根据输入信号的幅度值自动调整电路增益,使输出信号稳定在特定值附近.通过等精度测量方法,实现双路正弦波或方波的频率、相位差、占空比等要素的同步测量,其中100 MHz内的正弦波测频相对误差可控制在10-4内.利用NIOSⅡ软核驱动键盘、液晶屏等外围模块,并添加蓝牙接口,具有较强的实用性.