Keysight Technologies N774 C Series, User Manual

Page: 48 / 84

48 Keysight N774xC Series Multiport Power Meter User’s Guide
3 Definition of Terms
Specification wavelength range
The wavelength range for which all specifications and characteristics
apply, if not differently stated.
Spectral ripple (power meter; due to interference)
A coherent input signal causes optical interference1 between reflective
interfaces within the power meter's optical assembly, including the end
face of a connected fiber. Optical interference causes a wavelength
dependent periodic change of the power meter's responsivity. Spectral
ripple is defined as ± half the difference between the highest and the
lowest power resulting from the periodic change.
Conditions: Constant input power, constant state of polarization (SOP).
Connector as specified. Other conditions as specified.
Measurement: Using a laser source without spectral ripple or with known
(monitored) spectral ripple and linewidth < 100 MHz and stepping the
wavelength over the specified range. The periodic part in the
measurement result is separated by subtracting the polynomial 2
nd
order
fit (low frequency part).
Storage conditions
Allowed temperature and humidity range for the non-operating
instrument. Wait for acclimation to within the “Operating temperature”
before turning on the instrument.
Total uncertainty
The maximum relative difference U between measured (displayed) power
M and actual (true) power P for a specified set of operating conditions,
expressed in percent. Powers expressed in Watts. Excluding "Noise pp
(dark)" (see, Noise pp (dark) on page 44) and "Drift (dark)" (see, Drift (dark)
on page 42).
U = 100% * (M/P - 1)
Conditions: Operating conditions as specified. Other conditions as
specified.