基于FPGA和STM32的脉宽频率测量方法

摘要

In order to accurately measure the frequency of high frequency signals,overcome the shortcomings of the highest measured frequency is 80 kHz under the STM32F103 input capture mode.The paper proposed to use FPGA to divide the high frequency signal,and use software to adjust the factor of frequency division,the input high frequency signal can be divided and every component is below 80 kHz,then STM32F103 can measure them.In order to improve the measurement precision,we apply the repeated acquisition and bubble sorting,and then remove the maximum and minimum values,and take the average for the remaining values.The method improves the accuracy of frequency measurement.Finally,the measured value can be multiplied with the frequency division of FPGA to get the actual frequency.The test results show that the method is simple and has high precision and high frequency,it has certain practical value.%为准确测量高频信号的频率,克服STM32F103输入捕获模式下测得频率最高为80 kHz的缺点.提出用FPGA对高频信号进行分频,用软件编程调整分频因子,将输入高频信号分频到80 kHz以下,然后输入给STM32F103,采用脉宽测量法测得频率.为提高测量精度,采用多次采集,并冒泡排序,去掉部分最大、最小值,用剩余值取均值的滤波算法提高测量频率的精度.最后将测量值与FPGA的分频倍数相乘即可得到实际频率.测试结果表明:该方法实现简单、测量精度高、频率高,有一定的实用价值.