Agilent Technologies 8156A, Руководство по эксплуатации и программированию

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60
Using your Attenuator as a Variable Back Reflector
Setting Up the Software
4.2 Setting Up the Software
There are four factors that influence the back reflection of the
attenuator. These are
1. the insertion loss of the attenuator (
INS LOSS
),
2. the return loss of the attenuator (
RL INPUT
),
3. the reference return loss you are using (
RL REF
), and
4. the filter attenuation.
The return loss (RL) is calculated according to the equation
You edit the values for the insertion loss, the reference return loss,
and the return loss of the attenuator while you are setting up the
application.
You edit the value for the return loss while the application is
executing. The instrument calculates and sets the required value for
the filter attenuation.
Editing the Setup
Before you start setting up the back reflector application, you may
need to measure the following values, if you do not already know
them:
• The insertion loss of the instrument (see “Example, Setting the
Calibration” on page 42,
• The return loss of the instrument (with the output properly
terminated), and
• The reference return loss value.
RL dB
( )
10 10
RLIn pu t d B
( )
–
10
--------------------------------------
1 10
RLIn pu t d B
( )
–
10
--------------------------------------
–
 
 
 
 
10
2 Att dB
( )
In sLoss d B
( )
+
( )
RLRef d B
( )
+
( )
–
10
----------------------------------------------------------------------------------------------------------------
+
 
 
 
 
log – =
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