W9068A Datasheet, PDF (4/16 Pages) Keysight Technologies – Phase Noise X-Series

04 | Keysight | Phase Noise X-Series Measurement Application N9068A & W9068A - Technical Overview
Phase Noise Measurement Overview
As wireless communication technolo-
gies evolve in the commercial and
aerospace and defense industries,
it is clear that the driver to meet
demand for higher data rates, better
spectrum efficiency, and lower power
consumption is the digital technol-
ogy, such as digital signal processing
(DSP). It does not, however, devalue
the importance of high-purity, high-
stability signals—signal stability is
fundamental to successful modern
digital wireless communication sys-
tems. Phase noise is still one of the
most important characteristics when
evaluating the short-term stability of
a signal. Pressure to bring products
to market more quickly than ever
does not allow time for executing
multiple measurements across sever-
al instruments. An accurate, fast, and
easy-to-use phase noise measure-
ment tool is critical in the R&D and
manufacturing environments.
A variety of measurement techniques
have been developed to meet various
requirements for phase noise
measurements. The three most
widely adopted techniques are: direct
spectrum, phase detector, and two-
channel cross-correlation. Among
them, the direct spectrum technique
is the simplest and perhaps oldest
technique for making phase noise
measurements.
Keysight’s X-Series phase noise mea-
surement application is based on the
direct spectrum technique. The most
obvious advantage using the direct
spectrum technique for phase noise
measurements is that it can be real-
ized with a general-purpose signal/
spectrum analyzer. However, the
analyzer’s settings, such as resolu-
tion bandwidth (RBW) and internal
phase noise optimization loops, will
need to be adjusted based on offset
frequency to achieve the highest
measurement accuracy and speed.
Manually implementing phase noise
measurements with a signal analyzer
can be tedious and time consuming.
The X-Series phase noise measure-
ment application automates the
optimization processes for the signal
analyzer settings with one-button
measurements without user interfer-
ence.
Phase Noise Measurements
With the X-Series signal analyzers
or MXE EMI receiver and the phase
noise measurement application,
you can easily perform phase noise
analysis on various devices, such as
local oscillators and signal sources.
The analysis includes:
Measurement details
Log plot phase noise
Log plot measures SSB phase noise
(in dBc/Hz) versus offset frequencies
expressed in logarithmic scale.
–– Log plot: Single-sideband (SSB)
phase noise view in frequency
domain
–– Spot frequency: Phase noise
view in time domain including
carrier frequency drift measure-
ment
–– Monitor spectrum: Easy-to-use
simple spectrum view for a quick
check of your signal
–– IQ waveform: Easy-to-use simple
time domain view
This allows you to view the phase
noise behavior of the signal under
test across decades of offset fre-
quencies.
Figure 2. Log plot phase noise with a smoothed trace and decade table
turned on (taken from an MXA with N9068A)