浊度是水质的一项重要指标.为了快速、准确地测量浊度,设计了一种手持浸入式便携浊度计.浊度计基于透射光法,发光源使用带光电二极管( PD)的850 nm小功率激光管,激光管在发射电路地控制下产生1 kHz的调制光束,内置PD用于保持发光强度的恒定.光接收电路使用PD BPW82接收透过试样的光束,采用直流恢复电路消除低频背景光干扰,通过精密整流电路和滤波电路从调制信号中取出表示浊度的电压信号.软件上利用微处理器的运算能力简化了电路设计,省去了对数放大器.给出了标定算法和浮点数存储方法.%Turbidity is an important index of water quality. In order to rapidly and accurately measure turbidity of water,a new type of hand-hold immersion laser turbidimeter is designed. The method of measuring turbidity is based on transmitted light mode. The 850nm low power laser-diode with photo diode(PD) is used as light source. The laser-diode generates modulated beams at 1 kHz controlled by transmitting circuit. The light intensity is kept constant by the PD BPW82 photodiode receives the light beam transmitting from the samples. The DC restoration circuit is used to eliminate inteference of low-frequency background light. Turbidity signal is obtained through precise rectification circuit and filtering circuit from the modulating signal. The design of circuit is simplified and logarithmic amplifier is left out due to the operation ability of microprocessor. Calibration algorithm and storing methods of floating point number is given.
展开▼
