连续取N个采样值进行算术平均运算。N值较大时：信号平滑度较高，但灵敏度较低；N值较小时：信号平滑度较低，但灵敏度较高。-N consecutive samples taken arithmetic mean value calculation. Larger N values: smoothed signal is high, but the sensitivity is low　when the N value is smaller: smoothed signal is low, but higher sensitivity.