Agilent Technologies Agilent 8163A, Руководство пользователя

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Return Loss Measurement A Background to Return Loss Measurement with the HP 81534A
150
Agilent 8163A Lightwave Multimeter, Agilent 8164A Lightwave Measurement
System, & Agilent 8166A Lightwave Multichannel System, Fourth Edition
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 146 and in
“Measuring the Power Transmitted Through the Measurement Cable” on
page 146 respectively.
This gives the following two equations:
If we divide equation 11 by equation 12, this gives the following equation:
The loss variation,
∆
L , due to exchanging the reference cable for the
measurement cable is given by:
When you enter a value for the Front Panel Delta, < FPDelta >, the instrument
automatically performs the following calculation:
Figure 107 Generalization of Transmission Measurement
HP 81534A
P
src
k
1
k
2
Power
Meter
E
E aP
src
=
(12)
E
R ef
a
Re f
P
src
=
(13)
E
Mea s
a
Mea s
P
src
=
(14)
E
Re f
E
Me as
---------------
a
Re f
a
Me as
-------------- =
(15)
∆
L 10 –
a
Re f
a
Me as
-------------- 10 –
E
R ef
E
Meas
--------------- log = log =
(16)
RL RL
D U T
2
∆
L + =
(17)