60
Taking Standard Loss Measurements
Measuring the Return Loss
Calibrating for RL Measurements
Instead of measuring the
power transmitted to the
DUT, you can use the
assumed backreflection of
a glass-to-air transition as
a reference.
To calibrate the instrument for Return Loss measurements you have
to
•
enter the assumed backreflection and
•
measure and store the real backreflection and the power of
parasitic reflections of your setup.
1
Press S
OURCE
O
N
/O
FF
to switch the source on. The source
indicator lamp must be lit.
2
Press A
PPL
to activate the “Select Applications” menu.
3
Choose “Return Loss”.
4
Check the “Head” parameter on the display. If it does not
indicate the input to which you have connected the head, press
H
EAD
A
or
H
EAD
B
respectively.
5
Press
S
ETTINGS
.
If the refractive index of
the fiber you are using
differs largely from 1.458,
you can set any adequate
reference value.
6
Press
RL
REF
.
Use the rotary knob to change the value. 14.7 dB is the usual
backreflection of a well polished straight glass-to-air transition
based on a fiber refractive index of 1.458. Store with
E
NTER
or
E
NTER
.
Note:
Using the open-end reflection as a reference is simple and
convenient. However, you can also use any other defined
reflection, for instance a mirror.
7
Press
P
REVIOUS
to return to the measurement screen.
Figure 3-4
Return Loss Settings Display
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
