Agilent Technologies 8163A User Manual page 189

How to Use a Variable Optical Attenuator module Setting Attenuation and/or Power Levels
Figure 120 81560A/61A/70A/71A/73A Attenuation Offset
Figure 120 shows an α
of 1.651 dB 'added in' to the attenuation
Offset
factor α to calibrate for intrinsic insertion losses in the test setup.
The [PM -> Off ] softkey offered by the α
81566A/67A/76A/77A modules
parameter is functionally
Offset
equivalent to the [PM -> Off ] softkey offered by the P parameter.
Offset
You can use the [PM -> Off ] softkey to offset the difference between
the power measured by the internal powermeter and your reference
powermeter, as described "Calibrating Test Setups that use an
81566A/67A/76A/77A Attenuator module" on page 192.
• When the α parameter is selected, [PM -> Off ] writes to α
Offset Offset
• When the P parameter is selected, [PM -> Off ] writes to P
Offset Offset
These functions are mathematically identical.
Neither function is a measurement of total intrinsic insertion loss as
described in "81560A/61A/70A/71A/73A modules" on page 187, since
the insertion loss of the Attenuator module itself is not included.
For all Attenuator modules, the [Dsp -> Off ] softkey offered by the α
The Dsp -> Off softkey
parameter copies the negative of the current value of α into α
.
Offset
The α field now displays zero, and 'Offs' is displayed to show that the
offset has been applied.
You can now set the α parameter relative to α
.
Offset
189
Agilent 8163A/B, 8164A/B, and 8166A/B User's Guide, Fourth Edition