基于FPGA的数字频率计的设计  

Design of Digital Frequency Meter Based on FPGA

作　　者：徐冬冬[1] 闫嘉琪 XU Dong-dong;YAN Jia-qi(Nanjing University of Information Engineering,Nanjing Jiangsu 210044)

机构地区：[1]南京信息工程大学,江苏南京210044

出　　处：《数字技术与应用》2020年第6期120-121,共2页Digital Technology & Application

摘　　要：本设计选用FPGA作为数据处理与系统控制的核心,制作了一款超高精度的数字频率计,其优点在于采用了自动增益控制电路(AGC)和等精度测量法.AGC电路可将不同频率、不同幅度的待测信号,放大至基本相同的幅度,且高于后级滞回比较器的窗口电压,有效解决了待测信号输入电压变化大、频率范围广的问题.频率等参数的测量采用闸门时间为1s的等精度测量法.闸门时间与待测信号同步,避免了对被测信号计数所产生±1个字的误差,提高了系统精度.In this design,FPGA is selected as the core of data processing and system control,and an ultra-high precision digital frequency meter is made.Its advantages lie in the use of automatic gain control circuit(AGC)and equal precision measurement method.The AGC circuit can amplify the signals to be measured with different frequency and amplitude to basically the same amplitude,and it is higher than the window voltage of the post stage hysteresis comparator,which effectively solves the problems of large input voltage variation and wide frequency range of the signals to be measured.The measurement of frequency and other parameters adopts the equal precision measurement method with gate time of 1s.The gate time is synchronized with the signal to be measured,which avoids the error of±1 word caused by counting the measured signal and improves the system accuracy.

关 键 词：FPGA 超高精度数字盘频率计 等精度测量法 自动增益控制电路 

分 类 号：TM935.13[电气工程—电力电子与电力传动]