Weak Optical Signal Amplification Design, Acquisition System

A biological sensor is a device which has ability to detect specific physical quantity and get signals identified. Fiber optic biosensor is the combination of the optical system and biological detection systems which has a rapid pace of development. It has high sensitivity, anti-interference capability, and real-time detection of micro-probe and so on.The number of people suffering cancer is increasing as the ecological and environment problems become prominent. Data show that cancer rates in China are increasing every year. The problem about early detection of cancer has become a hot spot. The topics focus on the weak fluorescence signal acquisition and processing to do much signal exploratory research. This design can be used to detect fluorescent signals.In this paper the detection system of fiber biosensor is studied systematically. Some innovative works are done to the detection system based on the analysis of the sensing mechanism. The main contents are included as follows.First, optical fiber is used to transmit optical signal, reducing the wear and tear. Silicon photodiode is used to convert light signal, with pre-amplifier amplification. Noise is dealt with low-pass filter component; The AD7715 is used to convert the analog signal to digital signal, improving the accuracy of the conversion, removing the zero drift and gain error. Microprocessor control circuit is designed using STC12C5410 high-performance chip, enabling online programming to facilitate debugging development by downloading. LABVIEW of NI Company is used to design user interface with concise interface, making readers apply easily.The results show that the detection system can detect the slightly stronger light and display the signal in the interface designed. It can lay a foundation for the detection of weak fluorescence for later. This paper provides some suggestions and methods for improvement.