刘伟玲+杨彩双+冉多刚+康磊

摘 要： 通过对国内外现有恶臭测量方法的研究并结合现有光电检测技术，提出一种基于光吸收的恶臭信号采集系统。该系统基于光电比色法，采用双光路即每个采集电路模块设两个光路：一路参考光，一路信号光，两路信号采集时都使用了双边带调幅技术，相敏解调后的两路信号进入差分放大器做差，并且将差分信号用宽量程可编程增益放大器放大至理想AD值。该系统适合于采集宽范围浓度的恶臭信号，尤其适合于测量微弱的恶臭信号。该方案不仅能够抵抗干扰，降低噪声，还可提高采集的灵敏度，增大了量程，具有较好的应用前景。

关键词： 恶臭信号采集； 光电检测； 调幅技术； 嵌入式技术

中图分类号： TN152+.4?34； TM933 文献标识码： A 文章编号： 1004?373X（2017）08?0153?05

Research on stench signal acquisition system based on photoelectric detection technology

LIU Weiling， YANG Caishuang， RAN Duogang， KANG Lei

（School of Mechanical Engineering， Hebei University of Technology， Tianjin 300000， China）

Abstract： By studying the available stench detecting methods at home and abroad， a stench signal acquisition system based on light absorption is proposed in combination with the existing photoelectric detection technology. The system is based on the photoelectric colorimetry. The double optical paths are adopted in the system for each acquisition circuit module. One path is the reference light and another is the signal light. The double?sideband amplitude modulation technology is used for signal acquisition of the two paths. The dual?path signals after phase sensitive demodulation are transmitted into the differential amplifier for subtracting. The differential signal is amplified with the wide?range programmable gain amplifier until a satisfied A/D value is obtained. The system is suitable for acquisition of the stench signal in wide range， especially suitable for detection of the weak stench signal. The design scheme can resist the interference， lower the noise， improve the acquisition sensitivity and detecting range， and has a good application prospect.

Keywords： stench signal acquisition； photoelectric detection； amplitude modulation technology； embedded technology

0 引 言

恶臭[1]一直以来都是自然界很普遍的一种物质，它和人们的生活息息相关。人通过嗅觉感官可以感受到的恶臭物质有4 000多种[2]，我国监测防治的恶臭物质主要有8种，分别是：氨、硫化氢、苯乙烯、三甲胺、甲硫醇、二甲二硫、甲硫醚、二硫化碳，这些恶臭物质对人类均有一定的危害。随着人类对恶臭危害认知的不断增强，恶臭的防治工作逐步成为社会关注的重点。目前，量化恶臭的方法主要有两种：感官测定法和仪器测定法[3]。感官测定法依赖人的感官系统作为评判依据，主观依赖性强，长期测量会产生嗅觉疲劳，但其中三点比较式臭袋法[4]由于操作简单，仍然比较常用。仪器测定法按测定气体的成分分为单一成分测定法和复合成分测定法，该方法主要依赖于先进的分析仪器。……