Keysight Technologies N774 C Series, Руководство пользователя

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Keysight N774xC Series Multiport Power Meter User’s Guide 59
User Interface Reference
4
Where,
P
dB
is the power value returned in dB,
P
input
is the input signal level in Watts, and
Pref is the chosen reference power value in Watts.
How to Set the Wavelength
This is the wavelength value of the signal to be measured. The responsivity
of the Power Meter varies with wavelength. For accurate absolute power
measurement, you need to input the wavelength of the optical input. For
relative power measurements, this setting is not critical.
There are two ways to set the wavelength value:
• You can set the wavelength directly on clicking the Wavelength button,
see Display Wavelength and Power on page 55, or
• You go the Settings > Measurement Settings and then set the
wavelength.
How to Set the Calibration Offset
This is a calibration offset that you can enter to compensate for external
optical circuitry, for example, an attenuator, switch, or a 3 dB coupler. The
calibration offset, [Cal], is automatically subtracted from the input signal,
as expressed in dB.
where,
P
measured
is the adjusted value of the signal read in dBm,
P
input
is the input signal level in dBm, and
CAL is the calibration offset in decibels (dB).
P
measured
dBm
( )
P
input
dBm
( )
CAL dB
( )
– =