说明：  读取串口调试助手保存的TXT文档，将连续两个8位合并为一个16位数据，然后进行图形化显示，分析了幅频特性，然后对其进行了低通滤波并画图
(Read the serial debugging assistant TXT files saved in the continuous two 8 into a 16-bit data, and then graphically analyzed amplitude-frequency characteristics, and its low-pass filtering and drawing)