The Principle Of Spead Spectrum Reflectometer And Its Application

Aging wiring networks have been identified as an area of critical national and international concern.One of the particularly challenging problems is the location of intermittent faults that cannot be replicated on the ground.Firstly this paper describes some traditional test methods on fault location,and metrs of these methods Then it give a new test method called Spread Spectrum Time Domain Reflectometre.This method load a sine wave signal into the transmation signal, which is modulated from a binary pseudo-random sequence.And we can locate the point of failure by detecting the cross correlation between the reflected signal and a delay of the reference signal.The low test signal levels and high noise immunity of these test methods make them well suited to test for intermittent wiring failures such as open circuits,shortcircuits,and arcs on cables in aircraft in flight.This method is thown to be effective for wires carrying ACpower signals.At last the paper give the simulation of the SSTDR while the testing wires carring Mll-STD 1553 data.The results showns that this method is very efficient.