Dos & Don'ts
Viewing the traceMeasure Loss
Modify Test Parameters
More Useful References
"Virtual Hands-On" Termination
"Virtual Hands-On" Testing
compare fibers, open one trace then choose COMPARISON from the menu to
choose the second fiber or more,depending on the OTDR capability.
- Comparing two traces in the same
window is useful for confirming data collection and contrasting
different test methods on the same fiber.
- All OTDRs offer this feature, where you
can copy one trace and paste it on another to compare them. Here is an example of how you can use this feature.
- Measurements at Different Wavelengths
- Note that the two traces are taken from the same multimode fiber cable plant at different test wavelengths.
The major difference in the slope of the traces displays the
different attenuation coefficient of the fiber.
- The blue line (top) represents the attenuation
coefficient of the cable in at 1300 nm , the green line (bottom) represents
the same cable measured at 850 nm.
- There is also a noticable difference in
the reflectance at the splice. Variations in reflectance
due to the wavelength difference is not unusual.
- Other reasons you might want to compare
two traces includes:
- Compare several fibers in the same cable to see if they are different.
- Traces taken at different times to see
if the cable has changed.
- At different wavelengths, since fiber is
more sensitive to stress at longer wavelengths, this allows finding
stress points caused bu installation.
different pulse widths (below) to decide which setting gives the best
compromise between noise and resoluton or to find events lost with wide