Improve On Fiber Capacitance Drop Analyzer And Study Of Spectrum Drop Analyzer

Fiber capacitance liquid drop analyzer is a special instrument to attain thephysical and chemical characteristics of liquid stem from the theory of "liquid dropfingerprint spot based on the volume", which combines the fiber sensor with thecapacitance sensor. We take further study of double-wave fiber capacitance liquiddrop analyzer raised from the previous research. There are several problems we findthrough the experiments of double-wave fiber capacitance liquid drop analyzer. Firstly,the signal character is difficult to abstract during the whole growth process of liquiddrop due to the subtle fiber signal and the low definition of the liquid drop fingerprintspot as well. Secondly, the liquid drop fingerprint spot is shown as a parallel line atthe beginning, not altering with the growth of the liquid drop, which means the wholegrowth process of the liquid drop does not be recorded. Thirdly, there is couplingphenomenon between the two signals.According to the above, some research work was done to improve the instrumentfor gaining some achievements.Firstly, we find the connector assembly in the previous design is not suitableagainst the defect of subtle fiber signal change. The connector assembly in the earlierdesign can induce lots of noise in the signal transmission process, which cansubmerge the functional signal. We apply the new connector assembly to screen thesignal completely and thus the subtle signal become independent. Second, we analyze the rays' reflection in the liquid drop, which regards theproblem of liquid drop fingerprint spot being shown as a parallel line at the beginning.It was discovered that the input and output fiber positions do not fit well for detectingthe whole processing of a drop growth. So we redesign the input and output fiberpositions according to the reflection in liquid drop. The experiences have proved thatthe total liquid drop growth course is able to recorded by the new device.Thirdly, against coupling phenomenon between the two signals, we study theband-pass filter used to separate signals in the transaction circuit. Instead of theband-pass filter, a phase locked loop was chose. It is proved by experiences that phaselocked loop can separate two signals entirely.In addition, this paper reports the pilot study of micro fiber spectrum liquid dropanalyzer based on the Prof Qiu's theory, (Prof. Qiu Zurong, Tianjin University) ofcombination fiber capacitance liquid drop analyzer with micro spectrum analyzer, bywhich the problem of micro spectrum of narrow frequency band not carrying on thequalitative analysis can be resolved. The main parts of the study are shown as follows.1) Set up the device of experiments, and redesign the fiber signal transactioncircuit for the new optic source;2) Carry on the experiments with the device, which validate the feasibility of aninstrument based on the theory;3) Compile the special software that substance characteristics will be storiedbased on the theory of Prof. Qiu.