Keysight M9063A M9063a analog demodulation Datasheet

Keysight Technologies
M9063A Analog Demodulation
X-Series Measurement Application
for PXIe Vector Signal Analyzers
Technical Overview
–– Demodulate AM, FM, PM, or FM
stereo/RDS signals
–– Quad view, simultaneously displays
RF spectrum, demodulated
waveform, AF spectrum, and
demodulating metrics
–– Results for MPX, mono, stereo,
left and right channel of FM stereo
signal, and RDS/RBDS decoding
–– Selection of post-demod filters
–– PC-based SCPI remote interface
and manual user interface
–– Built-in context sensitive help with
SCPI command reference
–– Transportable license supports up
to four PXI VSA channels in one mainframe
Analog demodulation measurement application
Expand the capabilities of your M9391A and M9393A PXIe
vector signal analyzers (PXI VSAs) with Keysight Technologies, Inc. library of measurement applications - the
same applications used to increase the capability and
functionality of its X-Series signal analyzers. Eleven of the
most popular applications are now available for use with
Keysight's new M9393A PXIe performance VSA and the
M9391A PXI VSA. When you combine the raw hardware
speeds of the PXI VSAs and the X-Series measurement
applications for modular instruments, you can test more
products in less time, while ensuring measurement continuity from design to manufacturing.
The M9063A analog demodulation X-Series measurement
application for modular instruments transforms PXI VSAs
into easy-to-use transmitter testers for analog modulated
signals, helping you design, evaluate, and manufacture
your analog devices quickly and accurately. Even in the
modern digital world, the analog demodulation measurement application helps you to troubleshoot distortions due
to unintentional, analog modulation from digitally modulated transmitters --allowing you to stay on the leading
edge of your design and manufacturing challenges.
Figure 1. The quad view allows you to watch the RF spectrum,
demod, waveform, AF spectrum, and demodulation metrics
simultaneously.
Proven algorithms and a common user interface across
the X-Series analyzers and modular PXI VSAs create a
consistent measurement framework for signal analysis that
ensures repeatable results and measurement integrity so
you can leverage your test system software through all
phases of product development. The analog demodulation
measurement application is just one in a common library
of several measurement applications. You can further extend your test assets by utilizing up to four PXI VSAs with
one software license.
Keysight's X-Series applications for modular instruments
also include a unique "Resource Manager" that provides
direct access to PXI VSA hardware drivers for the fastest
power and spectrum-based measurements, while simultaneously using the X-Series applications for fast modulation
quality measurements and 89600 VSA for fast spectrum
measurements.
Figure 2. Resource Manager is included with all X-Series measurement applications for modular instruments.
2
Analog modulation and demodulation overview
Modulation is the process of translating some low-frequency or baseband
signal (such as voice, music, or data)
to a higher frequency (carrier signal).
The primary reasons for modulation
include allowing the simultaneous
transmission of two or more baseband signals by translating them to
different frequencies, and to take
advantage of the greater efficiency
and smaller size of higher-frequency
antennae.
Analog modulation is the most
fundamental modulation method. In
analog modulation, the variations to
the carrier are applied continuously
in response to the analog information
signal. By definition, the analog signal
is continuous in time and amplitude,
as opposed to a digital or discrete
signal.
A high-frequency carrier signal commonly has sinusoidal form. There are
two properties of a carrier signal that
can be altered: 1) the amplitude (A)
and 2) the angular position. Thus,
there are amplitude modulation (AM)
and angle modulation. Angle modulation can be further characterized as
either frequency modulation (FM) or
phase modulation (PM).
FM stereo is an enhancement to FM
that uses stereo multiplexing. An FM
stereo signal carries stereophonic
programs in which signals are transmitted for L (left) and R (right) audio
channels. Radio data system (RDS)
consists of the text information such
as traffic, weather, and radio station
information carried in the FM signals.
This information can be displayed on
the screen of the end-user's device.
RBDS is the United States version of
RDS.
Table 1 summarizes these three formats of analog modulation.
Analog demodulation is a reverse
process of the analog modulation. It
offers quantitative assessments for
analog modulation qualities. Analog
demodulation is not only essential in
testing FM or AM transmitters, but is
also a powerful troubleshooting tool
for analyzing unintentional signals
from digitally modulated transmitters
such as 2G/3G cellular phones, and
wireless LAN and WiMAX™ devices.
The FM demodulation measurement
is also an excellent alternative for
high-volume manufacturing of lowprice digital wireless devices, such
as Bluetooth®, where test throughput
and manufacturing costs are critical.
Table 1. Analog modulation formats
Modulation
format
Modulation nature
Primary characteristics
Amplitude modulation (AM)
Amplitude of carrier signal varies in direct proportion to the
instantaneous amplitude of the
baseband signal
AM depth, AM rate, modulation
distortion
Frequency modulation (FM)
Frequency of carrier signal varies in direct proportion to the
instantaneous amplitude of the
baseband signal
FM deviation, FM rate, modulation distortion
Phase modulation
(PM)
Phase shift of carrier signal
varies in direct proportion to the
instantaneous amplitude of the
baseband signal
Phase deviation, PM rate, modulation distortion
FM stereo/RDS
FM stereo is an enhancement to
FM that uses stereo multiplexing
consisting of a mono (L+R) signal,
a stereo signal (L-R) and a pilot
signal
FM deviation, FM rate, SINAD,
distortion, THD, mono to stereo
ratio, left to right ratio, 38 kHz
pilot carrier freq error and phase
error, RDS decoding
Choosing between X-Series applications
and 89600 VSA software
X-Series measurement applications provide format-specific, one-button measurements for X-Series analyzers and modular PXI VSAs. With
fast measurement speed, SCPI programmability, pass/fail testing and
simplicity of operation, these applications are ideally suited for design
verification and manufacturing. The 89600 VSA is the industry-leading measurement software for evaluating and troubleshooting signals
for R&D and design validation. Supporting numerous measurement
platforms and multiple measurement channels, the 89600 VSA provides flexibility and sophisticated measurements tools essential to find
and fix signal problems. Recent enhancements for the modular PXI
VSA platforms (89601B-SSA) provide fast spectrum measurements
with benchtop analyzer SCPI programming compatibility.
www.keysight.com/find/89600
3
Analog demodulation measurements
With the analog demodulation
measurement application, you can
perform analog modulation analysis
on various radio transmitting devices.
The analysis includes:
–– RF spectrum of the modulated
signal
–– Demod waveform (time-domain
view of the baseband signal).
FM stereo can view MPX, mono,
stereo, left or right demod waveforms.
–– AF spectrum (i.e., frequencydomain view of the baseband
signal). FM stereo can view MPX,
mono, stereo, left or right AF
spectrum.
–– Modulation metrics
–– AM depth
–– FM deviation
–– Phase deviation
–– Carrier power
–– Carrier frequency error
(FM and PM only)
–– Modulation rate
–– Distortion/total Vrms
–– Signal to noise and distortion
ratio (SINAD)
–– Total harmonic distortion
(THD)
–– Left to right ratio
–– Mono to stereo ratio
–– 38 kHz pilot frequency error
and phase error
–– RDS/RBDS decoding (including BLER, basic tuning and
switching info, radio text,
program item number and
slow labeling codes, clock
time, and date)
Measurement details
Modulation metrics
RF spectrum of the modulated signal
AM depth
This is the most traditional spectrum
analyzer measurement viewing the
modulated carrier signal power in
frequency domain. Prior to being
modulated, the signal power of a
sinusoidal carrier concentrates at the
carrier frequency. By contrast, the
modulated signal presents the power
redistribution over frequencies. Its
pattern depends upon the modulation format. (Refer to Figure 2.)
Demod waveform
This measurement retrieves the
baseband signal from the modulated
signal via the demodulation process,
and displays the baseband signal in a
pattern of modulation depth/deviation versus time. Since the modulation depth/deviation is directly
proportional to the instantaneous
amplitude of the baseband signal,
the measurement result helps to
intuitively evaluate the quality of the
baseband signal. (Refer to Figure 3.)
The AM depth measurement quantifies the amount of amplitude modulation to which the baseband signal
modulates the carrier signal. The AM
depth, also refers to AM modulation
index (m), and
is defined as:
Emax - Emin
m (in %) = —————
Emax + Emin
where, Emax and Emin are amplitudes (in voltage) of the modulated
signal at its peak and trout, respectively, in time-domain. The AM depth
ranges from
0 to 100%.
FM deviation
The FM deviation reflects the amount
of the frequency modulation to which
the baseband signal modulates the
carrier signal. The quantity being
measured is the peak frequency deviation that is the maximum frequency
excursion from the carrier frequency.
Phase deviation
AF spectrum
By applying the fast Fourier transform (FFT) to the baseband waveform, this measurement demonstrates the baseband signal behaviors
in frequency domain graphically. The
AF spectrum reveals the distortion
of the baseband signal clearly just
as the RF spectrum does for the RF
signal. (Refer to Figure 4.)
The phase deviation, also referred
to PM deviation, is a measure of the
amount of the phase modulation. The
quantity being measured is the peak
phase deviation (in radians) that is
the maximum phase excursion from
the average carrier phase.
FM and PM are two forms of angle
modulation. They are closely related,
as phase is the time integral of the
frequency, and frequency is the time
derivative of phase.
Carrier power
This measures the power of the carrier signal without the modulation.
Ideally, power for a sinusoidal carrier
signal is concentrated around its carrier frequency.
4
Carrier frequency error
Modulation distortion is usually measured in a relative term against the
total signal power:
This measurement reports the difference between the nominal frequency
and the actual frequency of the
carrier. It is only available for the FM
(Ptotal - Psignal )½
Modulation
Modulation
distortion
(in
%)
=
x 100%
and PM.
distortion (in %)
(Ptotal )½
Modulation rate
The modulation rate quantifies how
fast the modulation is and equates to
the frequency of the baseband signal
that modulates the carrier.
Distortion/total Vrms
Modulation distortion is the undesired alterations added to the modulated signal by modulation processes.
To assess the modulation quality of a
transmitter, the modulation distortion
needs to be quantified.
where, P total is the power of the total
signal; Psignal is the power of the
wanted modulating signal; and P total
- Psignal is the total unwanted signal
which can be further divided into the
components of noise and harmonic
distortion.
SINAD
Another commonly used distortion
measure is signal to noise and distortion ratio (SINAD). SINAD, in nature,
is the reciprocal of the modulation
distortion provided by the “distortion/total Vrms,” but the SINAD is
usually expressed in a logarithmic
term as follows:
SINAD (in dB) = 20 x log
(Ptotal )½
(Ptotal - Psignal )½
THD
The total harmonic distortion (THD)
measurement further isolates the
total harmonic distortion component
from the noise component in the total
unwanted signal. It helps the user
to troubleshoot the root causes of
modulation distortion.
Other features
Observing carrier frequency
settling time
The FM demod waveform provides
an effective way to see the frequency
settling of the carrier signal when it is
turned on. The simultaneous detectors give you more insights into the
carrier frequency settling behavior of
your transmitter output, such as how
quickly the carrier can be settled at
its nominal frequency value.
Selection of detectors
Four types of detectors are provided: positive peak (Peak+), negative
peak (Peak-), Peak/Peak average
((Pk-Pk)/2), and RMS. The Max Hold
values for each detector are also
displayed.
Comparing the result from the Peak+
detector and from the Peak- detector
allows you to check modulation symmetry. For symmetric modulation,
the Peak+, Peak-, and the (Pk-Pk)/2
detectors result in identical readings. For asymmetric modulation, the
readings generated by the Peak+ and
Peak- are different, and using the
(Pk-Pk)/2 values is recommended.
Figure 2. The RF spectrum view presents the modulated signal along with the results of
demodulation.
5
The RMS detector results in the RMS
(root-mean-square) value of modulation. It is a good choice when measuring noise or residual modulation,
where the RMS value is generally
more desirable than the peak value.
The RMS detector is also a good
choice for measuring non-sinusoidal
signals.
Post-demod filters
The post-demod filters help you to
optimize the measurement results by
filtering out undesired signals such
as harmonics, noise, and spurs from
the demodulated signal. You may
choose a high-pass filter (20, 50,
or 300 Hz), and/or a low-pass filter
(300 Hz, 3, 15, 30, 80, or 300 kHz)
from the available post-demod filter
bank to achieve the best demodulation results. For example, applying
an appropriate low-pass filter helps
minimize overshoot from squarewave modulation, such as frequency
shift keying (FSK).
Additionally, a CCITT filter, which
simulates the frequency response behavior of the human auditory system,
is also available to help you evaluate
the consequences of distortion of the
demodulated signal from the human
hearing perspectives.
Figure 3. Apply the "post-demod” filters to optimize analysis results for the baseband
(AF) spectrum.
To accommodate your pre-emphasized FM signals, the M9063A is also
equipped with four separate de-emphasis filters (25, 50, 75, and 750 μs)
for you to select.
Marker capabilities
The powerful marker capabilities
offered by the M9063A further add
great convenience to your analog demodulation measurements. You can
set up to 12 markers and define them
as “normal,” “delta,” or “fixed.”
Accelerating measurements
further
The PXI VSAs offer great advantages
in throughput with their industryleading speed for measurements
including the analog demodulation.
If your task demands even higher
throughput, the analog demodulation measurement application can
accommodate your needs. It offers
the flexibility to partially turn off
the measured parameters that the
flexibility for partially turning off the
measured parameters, which are not
required by your task, and can further
accelerate your measurement to save
every millisecond possible.
Figure 4. The demod waveform view displays the baseband signal in time domain.
6
FM stereo/RDS
MPX view
FM MPX consists of FM signal
multiplexing with the mono signal
(L+R), stereo signal (L-R), pilot signal
(at 19 kHz), and optional RDS signal
(at 57 kHz). Figure 5 shows the FM
stereo MPX view with four measurement windows. The top left window
contains RF spectrum, the bottom
left contains MPX AF spectrum, the
top right contains MPX demodulated
waveform, and the bottom right contains demodulation metrics with deviation, carrier power, carrier frequency
error, SINAD and distortion results.
Figure 5. FM stereo MPX view/display with RF spectrum, AF spectrum, demod waveform
and demodulation metrics results.
FM stereo mono/stereo/left/
right view
For FM stereo, mono signal (L+R) occupies the lower part of the baseband
spectrum (50 Hz to 15 kHz) in order
to maintain backward compatibility
with the previous monophonic FM
systems. The stereo signal (L-R) is
amplitude modulated onto a suppressed subcarrier at 38 kHz. A pilot
signal is transmitted at 19 kHz and
is used by the receiver to identify
a stereo transmission and reconstruct L and R audio signals from the
multiplexed signal. In the receiver,
mono and stereo signals will be
demodulated first and then the mono
signal (L+R) is added to the stereo
signal (L-R) to get the L signal, and
the stereo signal (L-R) is subtracted
to get the R signal. The mono/stereo/left/right views will display the
demodulated waveform, AF spectrum
and deviation, SINAD, distortion and
THD results for the selected channel.
Figure 6 is an example of FM stereo
left channel demodulation results.
Figure 6. FM stereo mono/stereo/left/right view/display with demod waveform, AF spectrum and demodulation metrics results.
7
RDS/RBDS decoding
results view
The main objectives of FM RDS/
RBDS are:
–– To enhance functionality for FM
receivers
–– To make the receivers more userfriendly by using features such
as PI (program identification), PS
(program service) name display,
and, if applicable, automatic tuning for portable and car radios.
RDS/RBDS uses the 57 kHz
subcarrier to carry the data at 1.1875
kbps bitrate. The 57 kHz subcarrier
is chosen to be the third harmonic
of the pilot tone. The deviation
range of the FM carrier due to the
unmodulated RDS/RBDS subcarrier
is 1.0 kHz ± 7.5 kHz. Figure 7 is an
example of the RDS/RBDS decoding
view showing the results of the BLER,
basic tuning and switching info, radio
text, program item number and slow
labeling codes, clock-time, and date
information.
Figure 7. FM stereo RDS/RBDS decoding results view/display with BLER and decoded
RDS information.
FM stereo numeric
result summary view
Figure 8 shows the numeric result
summary view with detailed MPX,
mono, stereo, left, right, pilot, and
RDS deviation, mod rate, SINAD
and THD results in the top section.
Furthermore, the left to right ratio,
mono to stereo ratio, RF carrier
power, RF carrier frequency error, 38
kHz carrier frequency error, and 38
kHz carrier phase error will be shown
on the bottom section.
Figure 8. FM stereo numeric result metrics view/display with deviation, mod rate, SINAD,
THD, left to right ratio, mono to stereo ratio and 38 kHz carrier frequency error, and
phase error.
8
Measurement details
All of these measurements are available with the press of a button (Table 2). The measurements are fully remote controllable via the IEC/IEEE bus or LAN, using SCPI commands.
Table 2. One-button measurements provided by the M9063A measurement application.
Technology
Measurement application
AM
PM
M9063A-2TP
M9063A-2TP
PXIe vector signal analyzer
FM
FM stereo/RDS
M9063A-2TP
M9063A-3TP
M9391A, M9393A
Measurement
RF spectrum
•
•
•
•
RF carrier power (dBm)
•
•
•
•
•
•
AF spectrum
•
•
•
MPX, mono, stereo,
left, right
Demodulated waveform
•
•
•
MPX, mono, stereo,
left, right
RF carrier freq error (Hz)
Demodulation
AM depth (%)
PM deviation (dB)
FM deviation (dB)
FM deviation (dB)
Peak+
•
•
•
•
Peak–
•
•
•
•
(Pk-Pk)/2
•
•
•
•
RMS
•
•
•
•
Modulation rate (Hz)
•
•
•
•
SINAD (dB)
•
•
•
•
THD (dB or %)
•
•
•
•
Distortion/total power
(dB or %)
•
•
•
•
Left to right ratio (dB)
•
Mono to stereo ratio (dB)
•
38 kHz carrier power (dB)
•
38 kHz freq error (Hz)
•
RDS/RBDS decoding
•
BLER
•
Basic tuning and switching Info
•
Radio text
•
Program item number and slow
labeling code
•
Clock time and date
•
9
Ordering information
Software licensing
and configuration
Transportable, perpetual license:
This allows you to run the application
using an embedded PXI PC controller or external PC, plus it may be
transferred from one controller or
PC to another. One software license
supports up to four modular PXI VSA
channels in one PXI mainframe.
Try before you buy!
You can upgrade!
Free 30-day trials of X-Series
measurement applications
provide unrestricted use of
each application’s features and
functionality on your modular
PXI VSA. See
www.keysight.com/find/M90XA
for more information.
Options can be added
after your initial purchase.
All of our X-Series application options are
license-key upgradeable.
The table below contains information on our transportable, perpetual licenses. For more information, please visit the
product web pages.
M9063A analog demodulation X-Series measurement application
Description
Model-Option
Analog demodulation
M9063A-2TP
FM stereo/RDS
M9063A-3TP
Additional information
Measurement consistency you can trust
Did you know that X-Series measurement applications for modular instruments use the same measurement
algorithms and programming commands as the bench top applications? This means you will get consistent
measurement results if you use Keysight bench top and modular equipment across the product development
cycle. Learn how this consistency and programming compatibility will increase the efficiency of your product
development cycle.
www.keysight.com/find/measurementconsistency
10
Recommended hardware configuration
M9391A PXIe vector signal analyzer configuration
Model-Option
Description
Notes
M9391A-F03, -F06
3 GHz or 6 GHz frequency range
One required
M9391A-B04, -B10, or -B16
40 MHz, 100 MHz or 160 MHz analysis
bandwidth
One required. -B16 recommended for fastest spectrum measurements with 89600
VSA software Option SSA.
M9391A-300
PXIe frequency reference
Recommended.
M9391A-UNZ
Fast tuning
Recommended. Highly recommended for
fastest spectrum measurements with 89600
VSA software Option SSA.
M9391A-M01, -M05, or -M10
Memory options (512 MB, 2 GB, or 4 GB)
Recommend 1 Gsa/4 GB memory
M9393A PXIe performance vector signal analyzer configuration
Model-Option
Description
Notes
M9393A-F08, -F14, -F18, or -F27
8 GHz, 14 GHz, 18 GHz, or 27 GHz frequency One required
range
M9393A-B04, -B10, or -B16
40 MHz, 100 MHz or 160 MHz analysis
bandwidth
One required. -B16 recommended for fastest spectrum measurements with 89600
VSA software Option SSA.
M9393A-300
PXIe frequency reference
Recommended.
M9393A-UNZ
Fast tuning
Recommended. Highly recommended for
fastest spectrum measurements with 89600
VSA software Option SSA.
M9393A-M01, -M05, or -M10
Memory options (512 MB, 2 GB, or 4 GB)
Recommend 1 Gsa/4 GB memory
Web
Related literature
–– N9063A & W9063A Analog Demodulation, Self-Guided Demonstration, literature number 5990-5921EN
–– Product page:
www.keysight.com/find/M9063A
–– Spectrum Analysis Amplitude and Frequency Modulation, Application Note 150-1, literature number 5954-9130EN
–– X-Series measurement
applications:
www.keysight.com/find/M90XA
–– N9063A & W9063A Analog Demod, Measurement Guide,
part number: N9063-90006
–– X-Series signal analyzers:
www.keysight.com/find/X-Series
–– M9391A PXIe Vector Signal Analyzer Datasheet, literature
number 5991-2603EN
–– M9391A PXIe vector signal analyzer
www.keysight.com/find/M9391A
–– M9391A & M9381A PXIe Vector Signal Analyzer & Generator
Configuration Guide, literature number 5991-0897EN
–– M9393A PXIe performance vector signal analyzer
www.keysight.com/find/M9393A
–– X-Series Measurement Applications for Modular Instruments
Brochure, literature number 5991-2604EN
11
12 | Keysight | M9063A Analog Demodulation X-Series Measurement Application for PXIe Vector Signal Analyzers - Technical Overview
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