What are the main factors affecting OTDR test error?
As the OTDR technology matures, its also constantly improve the measuring precision, but also have engineers friends sometimes reflect the test data and fault point position on the line have larger gap, what causes this situation?
Below small make up to you to summarize main factors influencing OTDR test error of four categories.
Set the instrument deviation produced by the refractive index of error: fiber refractive index of different type and manufacturer is different.
Using OTDR test fiber length, * * to the instrument set parameters, refractive index set is one of them.
When the refractive index of some cable does not can adopt the method of piecewise set at the same time, in order to reduce the test error caused by refractive index set error.
Improper selection range scope: OTDR test instrument distance resolution of 1 m, it refers to graphics zoom in to the horizontal scale of 25 m/division to achieve.
Instrument design is based on the cursor each step 25 to 1 full movement.
Every step in this case, the cursor movement, it indicates that the mobile 1 meter distance, so read the resolution of 1 m.
If the horizontal scale choose 2 km per case, every step is a cursor movement, will offset distance 80 meters.
Test, therefore, is to choose the range of scope is larger, the greater the deviation of test results.
Pulse width to incorrect: under the condition of the same pulse amplitude, pulse width, the greater the pulse energy, the dynamic range of OTDR, the greater the corresponding blind area is big also.