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Return Loss Measurement A Background to Return Loss Measurement
192
Agilent 8163A/B, 8164A/B & 8166A/B Mainframes, Sixth Edition
Measuring the Power Transmitted Through
the DUT
Remove the termination from the DUT and connect the DUT to a Power
Meter so that the power that is transmitted through the DUT can be
measured. This power is called E
il
Figure 116 Measuring the Power transmitted through the Device Under Test
You can use E
il
to calculate the insertion loss, see “ Calculating the
Insertion Loss of the DUT ” on page 196.
Calculating the Return Loss of the DUT
The system may be represented by the general diagram shown below:
The reflected power, measured by the instrument, (P), from the component
with the known reflection factor, is given by the sum of:
• the part of the power, reflected by the component, which is transmitted
through the coupler, and
• the reflections due to the measurement system.
M
il measurement
patchcord
DUT
Power Meter
E
il
Agilent 81610A
Reflectivity
R
DUT
Reflection-free
Termination
R
M
ref
P
ref
Agilent 81610A
Reflectivity
P
in
P
r
P
src
t
1
k
1
k
2
t
2