Keysight Technologies 8163A - Page 211

210 8163A/B, 8164A/B, 8166A/B User’s Guide
7 Return Loss Measurement
Figure 131 Generalization of a Return Loss Measurement
The transmitted power, (E), is directly proportional P
src
.
That is:
The constant a is a multiplier giving the proportion of power that the light
source emits that is measured by the power meter.
The constants a
Ref
and a
Meas
apply to the setups described in Measuring
the Power Transmitted Through the Reflection Reference on page 204 and
in Measuring the Power Transmitted Through the Measurement Patchcord
on page 205 respectively.
This gives the following two equations:
If we divide equation 11 by equation 12, this gives the following equation:
The loss variation, ΔL, due to exchanging the reference cable for the
measurement cable is given by:
Power Meter
E
Keysight 81610A
Reflection Reference
P
src
EaP
src
=
(12)
E
Ref
a
Ref
P
src
=
(13)
E
Meas
a
Meas
P
src
=
(14)
E
Ref
E
Meas
---------------
a
Ref
a
Meas
--------------=
(15)
(16)