OTDR automatic testing is in the case of not knowing the length of the fiber chain, I hope that the instrument can match a suitable range and pulse width to test.

About the most authentic automatic testing, should be able to achieve automatic range matching, pulse width automatic matching, test time automatically matched. Generally speaking, the completion of automatic test algorithm is not the same for different manufacturers, which has a great relationship with hardware. Different vendors have different hardware characteristics and different support for testing. I am familiar with the 34 OTDR, it uses the approach is gradually approaching the detection method. First with a large number of large pulse width to detect, and then based on the results to further accurate confirmation.

If the hardware isn't strong, it can't be done. Detailed on the long story, in a nutshell, is the laser rangefinder used in the fiber. If the fiber is damaged somewhere, the returned signal is comparable to the special, generally speaking, the space positioning accuracy in the rice level, is not particularly high, but about a large number of process testing, it is enough. At this root, it is COTDR to be able to improve the test accuracy through optical coherence. Brillouin scattering can also be used to test signals that compare small variations and can be used to measure strain dispersion.