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Keysight Technologies
AXIe and PXI Modular Test
Solution for Multiband SATCOM Monitoring
Application Note
Introduction
Today's satellite systems are required to deliver more complex data streams to and from terrestrial stations
than ever. The process of monitoring such massive multiband, multi-frequency satellite data streams becomes a
multifaceted and challenging environment. Present monitoring configurations usually consist of a dedicated test set
allocated to a specific band or frequency. For many satellite earth stations that means a room full of fixed hardware
and the resources to support it.
Going forward, a solution that consolidates multiple pieces of hardware into a single unit, whenever possible, has
the potential to reduce size, conserve resources and insure that the five-nines level of data reliability is maintained.
Evolving measurement solutions should be multifunctional across multiple bands and technologies, and be
integrated into as compact a footprint as possible.
In this application overview, the challenge of monitoring multiple 1.2 GHz satellite bands, from UHF through Ka, and
multiple modulation schemes is addressed. The proposed solution replaces individual test units with the smaller
PXIe and AXIe modular platform and the Keysight Technologies, Inc. 89601B Vector Signal Analysis (VSA) software.
Figure 1: Key components of the solution are the M9703A AXIe
high-speed digitizer, M9362A downconverter, M9352A IF amplifier
and the N5183A LO source.
Solution Solution details
After review of the user requirements, it is determined A high level view of the solution is shown in Figure 2. The
that AXIe and PXIe modular instrument platforms are well Antenna feed provides preselected signals of interest. The
suited for this application. Modular instrument attri- PXIe, AXIe and LXI hardware section down converts and
butes including excellent instrument density, expandable digitizes the signals. The hardware section is under the
multichannel support and high data bus speeds are ideal control of the Scanning and Display software application
for multi-band frequency monitoring. In addition, Keysight which orchestrates a fast scan of the antenna feeds from
modular digitizers are designed to work with Keysight's band to band. Shown on the right of Figure 2, is the Vector
VSA software providing the digital demodulation analysis Spectrum Analysis toolset which is the analysis engine
tool required for this application.
used for detailed digital modulation analysis.
The next step is to determine the components. The
The Scanning and Display SW application is a, non-stan-
preferred choice is the Keysight M9703A AXIe high-speed
dard, light-weight software utility developed by a user or
digitizer. This unit provides an 8-channel, 1.6 GS/sec at
12-bit resolution with on-board Digital Down Conversion application engineers. For this case, the software applica-
(DDC). A sampling rate of 3.2 GS/sec is also available tion is designed to scan the digitized data, perform a simple
without the DDC. Additional components included Key- FFT and then format and display the results for the operator
sight's M9362A PXI downconverter, the M9352A IF amp, to monitor. This allows the operator to monitor several fre-
the N5183A MXG microwave source as the LO source, quency bands at once with very quick display update rates.
and an alias filter. This relieves the 89601B analysis software from needing to
manage the scan.
For signal analysis, the Keysight 89601B VSA software is
utilized. The 89601B is the industry's premier vector signal Satellite pre-selection is user-provided to remove out-of-
analysis software for evaluating complex signal spectrum, band signals. The four frequency bands (C, Ku, K, and Ka)
modulation and time characteristics. are fed to the M9362A-DO-F50 quad downconverter. These
signals are downconverted by the frequency hopping LO,
This is the ideal solution set to collect multiple satellite processed, digitized and converted to the frequencies of
channels for output to the VSA software. Since the LO is interest (see Figure 2). The UHF band does not need to be
the most unwieldy component of this solution--it is large downconverted and thus can be captured directly with the
and heavy--a rather avant-guard approach to sharing the M9703A.
LO is implemented. The concept of hopping the LO across
the frequency bands offered the potential to remove four The requirement is to observe, record and analyze, in detail,
redundant components from the solution, minimize the SATCOM signal anomalies. For this solution, the appara-
footprint as much as possible and realize the goal of tus of choice is the Keysight M9703A digitizer. This unit's
increased field-portability. diverse feature set fits the requirements directly.
When an anomaly is noted in the monitored signal and the
Results operator instructs the device to capture a signal of interest,
the digitizer configures the DDC to increase the segment's
record size and take a high-resolution snapshot of the
Issue: Address the key requirement of using
narrow segment of the band containing the signal. This is
Commercial Off-The-Shelf (COTS) devices,
done at the hardware level by the advanced technology of
consolidating the data down converted signal
the DDC integrated into the digitizer. This is accomplished
streams to a single device for monitoring, and
make the solution portable. Using innovative in the hardware by the DDC, which is used to down convert
methodology, Keysight is able to present a this large record file and reduce it to a very manageable
SATCOM solution that meets these challenges. size, yet keep the required resolution bandwidth required
The critical components are Keysight's M9703A for digital demodulation.
AXIe high-speed digitizer, with its extremely
versatile Digital Down Conversion (DDC)
technology that allows edge-of-the-envelope
signal conversions, the fast and agile N5183A LO,
and Keysight's flagship 89601B VSA software.
Results: A unique SATCOM frequency scanning
and monitoring solution with standard products
used in novel ways.
Figure 2. Block diagram of the signal flow process.
Once captured and demodulated, the application software Ordering information
will use an automation link that will retrieve the digitally
demodulated data and display it on the VSA software. Model Description
Another capability of this approach is to archive captures 89601B 89600 VSA software, transportable
and file them for analysis at a future time. Archived files license
can be date and time stamped and have descriptions
M9502A AXIe chassis
attached to them.
M9018A PXIe chassis
One issue to be addressed is that sampling theory dictates M9021A Cable card (for cascade connect PXIe
when sampling a 1.2 GHz signal with only a 1.6 Gs/S to AXIe chassis)
bandwidth device, the possibility of producing images
M9703A AXIe 12-bit digitizer
is highly likely. Keysight's approach is a two-pass down
conversion on both the low and high side. One caution M9703A-SR2 1.6 GS/s sampling rate
is that very sharp cutoff filters are required to prevent M9703A-DDC Digital down-conversion firmware
aliasing and insure no spurious energy leaks into the signal M9703A-M40 4 GB (256 MS/ch) acquisition
being sampled (see Figure 3). In this case, preselection memory
is provided at the antenna; however, in cases where the M9036A PXIe controller
signal is not preselected, then a preselection filter is
M9036A-MO8 Memory option
required.
M9036A-W76 Widows 7-64 bit OS
Finally, what makes this solution viable for SATCOM M9352A IF amplifier (order 2)
application is the VSA software's ability to allow user M9362A-DO-F5 Quad downconverter
corrections for input paths. Because the front end down M9536A Embedded AXIe controller
converter has the potential to produce conversion loss, N5183A MXG (CW only)
correction for input path losses is required. The 89601B N5183A-540 W 40 GHz BW
series includes methods to correct for such losses, which N5183A-UNZ Fast frequency range
insures that the displayed data is accurate. The process
Y1202A PCIe cable x 8, 2M (for cascade
used to characterize and generate the correction data
connect PXIe to AXIe chassis)
needs to be done by the user. To assist in this effort,
Alias filters Stardard alias filters (need 4-8)
measurement support can be included in the application
software utility for the path loss characterization.
Software information
Together with knowledgeable staff, a unique SATCOM
frequency scanning and monitoring solution has been Supported operating Microsoft Windows XP
developed with standard products used in novel ways. systems (32-bit)
Microsoft Windows 7
Antenna PXIe, AXIe and LXI HW (32/64-bit)
Microsoft Windows Vista
(32/64-bit)
Linux
Keysight IO Libraries Includes: VISA Libraries,
Keysight Connection Expert, IO
Monitor
Want to know more?
Figure 3. Signal processing components. Product information
www.keysight.com/find/m9018a
www.keysight.com/find/m9021a
www.keysight.com/find/m9036a
www.keysight.com/find/m9362a
www.keysight.com/find/m9502a
www.keysight.com/find/m9703a
www.keysight.com/find/n5183a
05 | Keysight | AXIe and PXI Modular Test Solution for Multiband SATCOM Monitoring - Application Note
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