The pulse width, which determines the resolution of the measurements as well as the distance capability of the OTDR, should be set at the shortest width that allows the OTDR to see the end of the fiber. Acquire one trace, and look at it on the OTDR display. The above information shows typical values only and specific testing requirements may be different. You should always follow testing. A great rule of thumb is to set the range to at least 1. 5 times the estimated length of the fiber you are testing. If you set the range too short, you'll miss the end of the fiber entirely, leading to an incomplete. If you need more backscattered light to get good measurements, you can increase the pulse peak power or pulse width or send out more pulses and average the returned signals. Normally, within 10 km the pulse width can be set to 10ns or 30ns to realize effective data collection, if the fiber quality severely down, larger pulse width to be adopted for measurement The OTDR measurement range refers to the maximum. All OTDRs regardless of brand have four basic setup requirement i. the OTDR user is required to key in these four basic data parameters into OTDR in order to get good and accurate fiber trace analysis.
