Design Of Detection System For Weak Photoelectric Signal Based On LabVIEW

With the development of science and technology, the detection of weakphotoelectric signal becomes more and more important. Especially the weaksignal drowned in the strong noise attracts much attention at home and abroad.Aiming at this hotspot and diffculty, some of the traditional methods of weaksignal detection are exposed many deficiencies. For a long time, many scholars athome and abroad have been studying and exploring toward this directionindustriously, also have made some significant results.Weak photoelectric signal in strong noise will be discussed and analysedsystematacially in this paper, and then a detection system of weak photoelectricsignal is designed. Firstly, the possible noise existed or introduced from thehardware circuit is analysed in detail. Secondly, slave machine is designed,which mainly makes the photoelectric signal for a series of process, such asphotoelectric conversion, amplification and filtering. The slave machine consistsof five parts that are photoelectric conversion, preamplification, multistageamplification, active filtering and data transmission. The slave machine will setthe collected target signal to the PC that is LabVIEW8.5software for processingthrough the MPS-010501data acquisition card. Then I use the detection methodsof weak signal to denoise for the signal with noise through programming in thePC, then compare and analyse the results in order to find out the advantages anddisadvantages, so we can make use of the advantages with improvement andinnovation. And a method of adaptive narrowband power spectrum filtering is putforward, combined with the good real-time of LabVIEW, then it turns out to bethis method has the advantage and feasibility.Finally, via testing the whole weak photoelectric signal detection system, it shows us that the designed system could detect the weak photoelectric signalunder strong noise effectively. Comparing the simulation results, we know thatthe adaptive narrowband power spectrum filtering is very efficient for thedetection and extract of weak periodic signal, and it can detect the minimumsignal-to-noise ratio as low as-11.7dB. This design meets the requirement of thedetection of weak photoelectric signal under the strong noise basically, and thecost of whole system is low. So it has a good prospect of application that showsthe advantages of virtual instrument LabVIEW.