基于相位差分的FPGA瞬时测频的实现

Implementation of instantaneous frequency measurement based on phase difference by FPGA

为了实现在信噪比较高条件下的高精度测频,考虑在不同时刻噪声的不相关性,利用多点平均的方法对相位差分算法进行了改进,通过Matlab的仿真表明了该算法在信噪比较高的条件下,具有稳定的,较好的测频性能,且拥有较低的计算量。最后利用FPGA技术在硬件上实现了该算法,结构清晰简单,实时性高,可模块化和功能拓展,通过实际的测试,该算法在信噪比较高的条件下,可以获得较好的测频效果,测频误差小,可以满足实际工程需求。

In order to realize the high precision frequency measurement in high SNR condition,the phase difference algorithm was improved with multi point average method in consideration of the noise irrelevance at different time.The simulation in Matlab shows that the algorithm has a stable frequency measurement performance under the condition of high noise,and low calculated quantity.The algorithm was implemented on the hardware by using the FPGA technology.Its structure is compact and simple.It has the characteristics of high real-time performance and function development,and also can be modularized.The actual test indicates that the algorithm can obtain better effect of frequency measurement under the condition of high SNR,frequency measurement error is small,and can satisfy the actual engineering requirements.