针对水体有机物离散三维荧光光谱测量,设计了基于可变增益与积分放大技术的微弱荧光信号高灵敏、 大动态范围检测电路和控制软件,进行了实验验证并应用于水体有机物离散三维荧光在线测量系统。 在电路设计中,自动程控CMOS多路模拟开关根据输入信号强度实现了前置增益放大器的调节,基于 开关型电荷积分器实现了微弱脉冲荧光信号的同步积分放大。结果表明所设计电路最低检测电流为0.09 μA, 动态检测范围为0.09 μA～0.21 mA, 检测限提高了79.25倍。 在水体有机物离散三维荧光测量系统的应用中,保证了系统的检测灵敏度, 并提高了荧光信号的动态检测范围,实现了水体有机物的高精度测量。

According to the discrete three-dimensional (3D) fluorescence spectrum detection of organic matter in water, the high sensitivity and large dynamic range detection circuit and control software of weak fluorescence signal based on the variable gain and integral amplification technology are designed. Experiment verification is carried out and it’s applied to the on-line detection system for discrete 3D fluorescence of organic matter in water. In the designed circuit, according to the input signal intensity, automatic program control CMOS multi-channel analog switch is used to realize the adjustment of front gain amplifier. Based on the switching charge integrator, the synchronous integral amplification of weak pulse fluorescence signal is realized. Results show that the minimum detection current of the designed circuit is 0.09 μA, dynamic detection range is 0.09 μA～0.21 mA, the detection limit is increased by 79.25 times. In the application of discrete 3D fluorescence detection system of organic matter in water, the system detection sensitivity is guaranteed, and dynamic detection range of fluorescence signal is improved. The high precision measurement of organic matter in water is realized.