How To Reference Another Power Measurement Channel - Agilent Technologies 8163A User Manual

How to Measure Power
Agilent 8163A Lightwave Multimeter, Agilent 8164A Lightwave Measurement System, & Agilent 8166A Lightwave
Multichannel System, Fourth Edition
Where,
REF is the reference, and
P
measured
on page 73).
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 (dB) = P
display
or
Where:
P
display
P
measuredA
P
measuredB
REF
N O TE 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.
To reference another channel:
1 Move to the Power Meter channel and press the [Details] softkey.
2 Move to the [Ref Mode] parameter and press Enter.
3 Move to the channel number you want to reference, using the cursor key, and
press Enter. For example, in Figure 44, you could choose 3.1 (for channel 3.1).
is the absolute power level (see "How to Set the Calibration Offset"
(dBm) − P
measuredA measuredB
( )
P dB = 10 log
display
is the displayed relative power,
is the absolute power level (see "How to Set the Calibration
Offset" on page 73) measured by the current Power Meter, and
is the absolute power level (see "How to Set the Calibration
Offset" on page 73) measured by the Power Meter you choose to
reference, and
is the reference level in decibels (dB).
Power Measurement
(dBm) − REF(dB)
( )
P W
measu redA
(
------------------------------------- – REF dB
( )
P W
measu redB
)
75