Design And Utilization In Detector Of Defective Cable Based On System Of A Programmable Chip And Time-Frequency-Domain Reflector

Cable as a communication media is widely applied into many important domain such as instrument,electric power,communication and so on.There is something wrong with cable on the condition of destroying,submerging and aging,which is inevitable.so that ,it is urgent for good performance detector of the defective cable to decrease the loss,how to detect the potential faults and how to resume the defective cables with the implements.There are mainly electric-bridge detectors,time-domain reflectors (TDR) and frequency-domain reflectors (FDR) on the basis of detecting principium. Electric-bridge detectors are limited to realize high precision by their detecting principium;TDR's precision is entirely relied on time-base circuits and sampling frequency,high precision means expensive cost,on the same time,TDR can't detect potential defaults or detect the cable transporting high frequency and RF signals, only might detect the cables transporting DC and baseband signals;FDR's principium is mainly based on frequency spectrum and vector analysis.High precision materializes its advantage,otherwise cubage and cost aren't easy to be controlled because of complex arithmetic,which is limited in portable appliance and wide popularization.In a word,it is a important task to study and realize detector of the defective cable character on consolidating high precision,small cubage and low lost.What the paper has mostly done including the following facts: (1) Having Studied the existing detectors of defective cable,then,evaluating the advantages and disadvantages of the electric-bridge detectors,TDR and FDR; (2) On the one hand putting forward the time-frequency-domain reflector (TFDR),it combine TDR principium with FDR principium to overcome that TDR can't detect potential defaults or detect the cable transporting high frequency and RF signals and that FDR's cubage and cost aren't easy to be controlled because of complex arithmetic;on the other hand importing system of a programmable chip(SOPC) to designing the detector, realizing arithmetic on software ,decreasing expense and shrinking cubage;(3)Firstly adopting the correlation check and judge with the time-frequency-time crossing function,which overcomes the possible incorrect judge region from TDR's voltage judge and FDR's frequency judge;(4) Having realized detector of the defective cable based on SOPC and TFDR on the condition of enterprise standard. During the course of designing, the topmost object furthest consolidates high precision,small cubage and low lost and the principle is precision firstly, then cubage and cost。Experimenting to validate the detector's performances ,characters on the following: gaining the precision about 0.6~0.8 meter on the full scope,realizing the portable instrument on the basis of small cubage, 200mm×120mm×60mm,decreasing the cost,<2000 yuan RMB.On the condition of the comparative cost and cubage,precision is improved to the five times,from 3 meter to 0.6~0.8 meter; On the condition of the comparative precision, cost is decreased to the one-fifth of FDR's or high performance TDR's.All in all,the aim of design is turned into the reality.