Research Of The Signal Conditioning Of Distributed Optical-fiber Safety Monitoring System

Distributed optical-fiber Safety Monitoring System is used widely in continuous real-time monitoring such as dam, expressway, bridge Oil and Gas Pipelines jail. The common monitor can't satisfy requirement in applications. For Distributed optical-fiber Safety Monitoring System is durable stable reliable and spread all over the area monitored, it has broad prospects.As mentioned Safety Monitoring System, the signal algorithm and the quality of signal is important for upper computer's ability to estimate incident of invading. More important is that the quality of signal is depended on ability of Opto-Electrical transducer circuit. It is necessary that we research the circuit which has low noise, enough signal bandwidth, high SNR, and is stable because Opto-Electrical converter has problems which presents high noise voltage, contradiction between signal bandwidth and output noise voltage, instability in Radio Frequency System.The project research as follow for problem which Opto-Electrical converter has.①Analyze the stability, signal bandwidth and noise of Basic Opto-Electrical transducer circuit.②Based on analysis of Basic Opto-Electrical transducer circuit and comparison two kinds of Opto-Electrical transducer circuit which are improved; we choose the Composite Amp Opto-Electrical transducer circuit which performs better than circuits as mentioned.③Not only the Composite Amp Opto-Electrical transducer circuit brings in the additional noise from the second OP AMP and does not lose the signal bandwidth, but also decreases output noise voltage of circuit obviously.④The test which calculates and comprises the output noise voltage from two kinds of Opto-Electrical transducer circuit proves that the Composite Amp Opto-Electrical transducer circuit can effectively decrease the output noise voltage and enhances SNR.