基于匹配滤波的激光尘埃粒子计数器信号处理方法研究

Research on Signal Processing Method of Laser Particle Counter Based on Matched Filter

为提升激光尘埃粒子计数器的计数准确率,基于匹配滤波器设计粒子计数器信号预处理方法。分析粒子信号的特征,通过归一化后累加的方法获得粒子的典型波形。以该典型信号作为匹配模板,将激光粒子尘埃计数的原始信号与匹配模板进行离散卷积操作,得到高信噪比的输出信号。试验结果表明,针对原始幅值在55~262 mV、噪声均方根值约为6.74 mV的粒子信号,经该匹配滤波方法后,信噪改善比均优于1.56。该方法对比数字滤波器方案,能更有效提升输出信号信噪比,为粒子的准确检测和识别提供良好基础。

In order to improve the counting accuracy of laser particle counter,a signal preprocessing method based on matched filter is designed.The characteristics of the particle signal are analyzed,and the typical waveform of the particle is obtained by the method of normalization and accumulation.Using the typical signal as a matching template,the original signal of laser particle counter and the matching template are discretely convolved to obtain an output signal with a high signal-to-noise ratio.The experimental results show that the signal-to-noise improvement ratio is better than 1.6for particle signals with original amplitude of 55~262mV and root mean square value of noise of about 6.74mV.This method effectively improves the signal-tonoise ratio of the output signal,and provides a good foundation for the accurate detection and recognition of particles.