摘要
提出了一种新型的基于声光可调谐技术的近红外光谱仪控制系统的实现方案.该控制系统主要由射频信号源、红外信号检测和基于USB接口的数据采集电路三部分组成.射频信号源采用双模锁相环频率合成技术,实现了在38MHz—150MHz范围内的频率输出,其经功率放大电路后驱动AOTF来实现衍射光的波长扫描控制.红外信号检测电路采用了一种新颖的电学调制和锁相放大技术,实现了提高检测信噪比的目的.USB控制器是该系统的控制核心,它负责接收计算机发出的波长扫描指令和实现射频信号源的输出频率设置,并以块传输管道向计算机发送A/D采样数据.实验结果表明该光谱仪能实现1μm—2.2μm范围内稳定可靠的测量,分辨率为17nm.可广泛地应用于各种在线光谱分析场合.
The control system for a novel near-infrared spectrophotometer（ NIRS）based on an acousto- optic tunable filter is introduced. This control system consists of a radio-frequency generator, an infrared detecting circuit and a data acquisition circuit based on USB. A dual modulus PLL （phase locked loop） synthesizer is adopted to produce the radio-frequency generator operating between 38MHz and 150MHz,which is power amplified to drive the acousto-optic tunable filter to implement wavelength scanning of diffracting beam. To detect infrared signal, a novel electric modulation method and a lock-in amplifier technology are used to improve signal-noise ratio. A USB controller is the kernel of this control system,which not only receives wavelength scanning instructions from computer and changes the output frequency of radio frequency generator accordingly,but also sends sampling data to computer via bulk-transfer pipes. Experiments show that this NIRS works stably between 1μm and 2. 2μm, and the spectral resolution is 17nm. And it can be widely applied in various online spectral analysis fields.
出处
《应用基础与工程科学学报》
EI
CSCD
2006年第1期137-143,共7页
Journal of Basic Science and Engineering
基金
"十五"国家科技攻关重大项目(项目编号:2004BA210A02)
