Agilent Technologies 8163B, Руководство пользователя, Страница: 89 / 466

How to Measure Power Power Measurement
Agilent 8163A/B, 8164A/B & 8166A/B Mainframes, Sixth Edition
89
When you press the [Dsp->Ref] softkey, the absolute power level, the
power value in dBm or Watts, is stored as the reference, that is:
REF = P
measured
Where,
REF is the reference, and
P
measured
is the absolute power level (see “ How to Set the Calibration Offset ”
on page 87).
The [Dsp->Ref] softkey is displayed if you move to a power measurement
channel.
How to Reference Another Power Measurement Channel
You can use the reference mode, [Ref Mode], to reference another Power
Meter’s current power level. If you choose this mode, the reference of the
channel continuously updates to the current power value measured by the
other channel.
The following equations describe how the power in dB is calculated if you
reference another channel:
P
display
(dB) = P
measuredA
(dBm)
−
P
measuredB
(dBm)
−
REF(dB)
or
Where:
P
display
is the displayed relative power,
P
measuredA
is the absolute power level (see “ How to Set the Calibration Offset ”
on page 87) measured by the current Power Meter, and
P
measuredB
is the absolute power level (see “ How to Set the Calibration Offset ”
on page 87) measured by the Power Meter you choose to reference, and
REF is the reference level in decibels (dB).
You can only set the reference level, REF, in decibels (dB) when you
reference Power Meter’s current power level. This reference level is stored
in separate memory than the absolute reference level.
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