Changing The Index Of Refraction; Running An Autotest - Fluke DSP-FTA420 User Manual

DSP-FTA420/30/40
Users Manual

Changing the Index of Refraction

The index of refraction, n, is the ratio of the velocity of light in free space to
the velocity of light in a fiber. This value is used with the measured
propagation delay to determine fiber length.
The test tool can store n values for 50 µm multimode, 62.5 µm multimode and
singlemode cable types. One set is for the standard tests and eight sets are used
for custom tests.
If you need to change the factory setting for n to match the fiber you are
testing, proceed as follows:
Turn the rotary switch to SETUP. Use $ Page Down and E to
1.
find and highlight the index of refraction setting.
Use DU and LR to adjust the setting to the desired value; then press
2.
E.
If you change n for a custom test setup, this n value will be used only for that
custom test. If you are not setting up a custom test, the new n value will be used
for all tests except custom tests.

Running an Autotest

The Autotest certifies dual-fiber links based on the fiber standard you select.
An Autotest can be used to check optical power loss, fiber length, and
propagation delay.
You can also use the Autotest in Far End Source Mode to measure loss on a
single fiber. Using Autotest, rather than a Single Test, gives the option of
saving the test results. If you use an optional multimode source, such as the
Fluke FOS-850/1300 source, Autotest measures optical power loss only.
16