Keysight Technologies N774 C Series, User Manual

Page: 44 / 84

44 Keysight N774xC Series Multiport Power Meter User’s Guide
3 Definition of Terms
Maximum safe (input) power
The maximum input power that can be applied to any port of the power
meter or attenuator without permanent change to its characteristics.
Attention: Applying more than the specified power might damage the
power meter or attenuator.
Minimum averaging time
The minimum selectable averaging time.
Noise pp (dark)
Specifies the peak-to-peak (pp) change of displayed power over time with
zero input power (dark), excluding "Drift (dark)" (see, Drift (dark) on
page 42) for the N7744C and the N7745C only. Powers expressed in
Watts.
Conditions: All ports dark. Averaging time as specified. Other conditions
as specified.
Measurement: As for “Drift (dark)”. From the measured P
i
and the fitted
curve F
i
the noise curve N
i
= P
i
- F
i
is calculated.
The noise N is
N = max
i
{N
i
} - min
i
{N
i
}
Noise 2 sigma (dark)
Specifies twice the standard deviation of the measured dark power (with
zero input power), excluding “Drift (dark)”. Power are expressed in Watts.
Conditions: All ports dark. Averaging time as specified. Other conditions
as specified.
NOTE
For input powers > 20 dBm, clean connectors in good condition are vital
to avoid thermally induced fiber damage.
NOTE
The noise pp specification (rather than noise 2 sigma) is given for legacy
reasons.