PXI T E S T R E P O R T November 2010 PXI TEST REPORT • November 2010 37 www.tmworld.com A ccording to the PXISA (PXI Systems Alliance), the industry passed a major milestone earlier this year: More than 100,000 systems have been developed since the PXI standard was released in 1997, with more than 600,000 modules shipped. I spoke with PXISA board member Matthew Friedman of National In- struments, who is also the PXISA marketing co-chairman, to discuss what will keep PXI growing toward that next 100k. Q. What does achieving this milestone say about PXI? A. Achieving this milestone is an in- dicator that PXI is the proven stan- dard for automated test. Another indi- cator is PXI’s presence at this year’s Autotestcon [September 13–16, Or- lando, FL]. PXI first appeared at the show 12 years ago; this year, the ma- jority of the show’s vendors were ei- ther PXISA members or PXI custom- ers. Also, we’ve been seeing very ag- gressive movement of test vendors into PXI. Seven new members have joined PXISA, many of which were tradi- tional ATE or VXI vendors. As a result of all this, we expect that 2011 will be the strongest year ever for PXI as it continues its substantial growth. Q. How has the PXISA encouraged this growth? A. The PXISA has been doing a lot of work in emerging markets such as China. We’ve held several Technology and Application Conferences in Tai- wan and China that have been very heavily attended. Several Chinese companies have already joined the PXISA, including Beijing Aerospace Measurement and Control. Also, the PXISA technical committees are con- tinuing to evolve the standard to take advantage of the latest technologies. The most recent example is the PXImc multicomputing specification, which will enable even higher-perfor- mance computing and data-streaming capabilities. Q. When can readers expect PXImc hardware to become available? A. It’s a new technology, and the technical committee just completed work to ensure all components are in place for vendors to begin releasing products. The hardware and software specifications were made available in late 2009, but equipment has been waiting for a final piece—the shared software component that helps ensure interoperability among boards. That software component was finalized in August and is now available to all PXISA members. Prototypes of PXImc are already being demon- strated. For example, at this year’s NIWeek [August 3–5, Austin, TX], we featured a working PXImc system with four interconnected servers at- taining 50 GFLOPS and 600-Mbyte/s sustained data rates. Q. What trends do you see in PXI for the coming years? A. Beyond the new computing capa- bilities enabled with PXImc, we will continue to see higher-performance RF measurement capabilities. This is evi- dent in the new multichannel architec- tures enabled by PXI and as modules reach new frequency ranges. You will also see new levels of instrument pro- grammability as users will be able to go beyond the driver level and recon- figure the instrument’s FPGA to meet their exact measurement need. Q. How do new emerging standards such as AXIe fit in? A. AXIe borrows many elements from PXI, which further validates PXI’s architecture, but it is hard to see just where AXIe will fit. The trend in instruments is toward smaller form factors and lower power, because as technology evolves, we’re getting more into less space while using less power. While some applications may need the large size that AXIe offers, we still see PXI remaining the dominant standard for automated test. PXISA is keeping up the momentum By Richard A. Quinnell, Contributing Technical Editor Matthew Friedman Board Member, PXISA Senior Product Manager, National Instruments 38 Guest Commentary: One success story drives another 38 Highlights: NI, Geotest intro- duce new products 40 PXI RF development shifts focus INSIDE THIS REPORT
Transcript
PXIT e s T R e p o R T
November 2010
PXI TesT RePoRT • November 2010 37w w w . t m w o r l d . c o m
According to the PXISA (PXI Systems Alliance), the industry
passed a major milestone earlier this year: More than 100,000 systems have been developed since the PXI standard was released in 1997, with more than 600,000 modules shipped. I spoke with PXISA board member Matthew Friedman of National In-struments, who is also the PXISA marketing co-chairman, to discuss what will keep PXI growing toward that next 100k.
Q. What does achieving this milestone say about PXI?A. Achieving this milestone is an in-dicator that PXI is the proven stan-dard for automated test. Another indi-cator is PXI’s presence at this year’s Autotestcon [September 13–16, Or-lando, FL]. PXI first appeared at the show 12 years ago; this year, the ma-jority of the show’s vendors were ei-ther PXISA members or PXI custom-ers. Also, we’ve been seeing very ag-gressive movement of test vendors into PXI. Seven new members have joined PXISA, many of which were tradi-tional ATE or VXI vendors. As a result of all this, we expect that 2011 will be
the strongest year ever for PXI as it continues its substantial growth.
Q. How has the PXISA encouraged this growth?A. The PXISA has been doing a lot of work in emerging markets such as China. We’ve held several Technology and Application Conferences in Tai-wan and China that have been very heavily attended. Several Chinese companies have already joined the PXISA, including Beijing Aerospace Measurement and Control. Also, the PXISA technical committees are con-tinuing to evolve the standard to take advantage of the latest technologies. The most recent example is the PXImc multicomputing specification, which will enable even higher-perfor-mance computing and data-streaming capabilities.
Q. When can readers expect PXImc hardware to become available?A. It’s a new technology, and the technical committee just completed work to ensure all components are in place for vendors to begin releasing products. The hardware and software specifications were made available in late 2009, but equipment has been waiting for a final piece—the shared software component that helps ensure interoperability among boards. That software component was finalized in August and is now available to all PXISA members. Prototypes of PXImc are already being demon-strated. For example, at this year’s NIWeek [August 3–5, Austin, TX], we featured a working PXImc system with four interconnected servers at-
taining 50 GFLOPS and 600-Mbyte/s sustained data rates.
Q. What trends do you see in PXI for the coming years?A. Beyond the new computing capa-bilities enabled with PXImc, we will continue to see higher-performance RF measurement capabilities. This is evi-dent in the new multichannel architec-tures enabled by PXI and as modules reach new frequency ranges. You will also see new levels of instrument pro-grammability as users will be able to go beyond the driver level and recon-figure the instrument’s FPGA to meet their exact measurement need.
Q. How do new emerging standards such as AXIe fit in?A. AXIe borrows many elements from PXI, which further validates PXI’s architecture, but it is hard to see just where AXIe will fit. The trend in instruments is toward smaller form factors and lower power, because as technology evolves, we’re getting more into less space while using less power. While some applications may need the large size that AXIe offers, we still see PXI remaining the dominant standard for automated test.
PXISA is keeping up the momentumBy Richard A. Quinnell, Contributing Technical Editor
Matthew FriedmanBoard Member, pXIsAsenior product Manager,National Instruments
38 Guest Commentary: one success story drives another
38 Highlights: NI, Geotest intro-duce new products
40 PXI RF development shifts focus
InsIde this report
PXI T e s T R e p o R T
38 November 2010 • PX I TesT RePoRT w w w . t m w o r l d . c o m
g u e s T c o M M e N T A R y
the ability of a product or a family of products to main-tain sales levels during an economic downturn is a
good indication about the strength of an industry in gen-eral and about a product family in particular. Being able to grow market share during an economic downturn, as PXI has done, is even more impressive and rarely happens.
Plus, with the projected future compound annual growth rate of greater than 17% that Frost & Sullivan predicted in December 2008, PXI remains on track to grow its test-and-measurement market position.
These market trends bode well for both current and future PXI customers as well as PXI suppli-ers. The success of PXI motivates PXI suppliers to invest more in R&D and as a result, there are better, faster, and more cost-effective products. These additional products and capabilities lead to more applications for PXI and better ways to address applications and markets already being served by PXI. The result is more customer suc-cess stories, which is why the PXI market segment has continued to grow.
The Autotestcon 2010 conference (September 13–16, Orlando, FL) was a testimony to the success of PXI in
general and PXI customers and applications in particular. With more than 25 exhibitors demonstrating PXI products or systems, combined with the introduction of many new PXI products, including high-performance digital I/O and microwave products, and the addition of Agilent Technolo-gies as the newest sponsor member of the PXISA (PXI Systems Alliance), PXI continued to demonstrate its mar-ket appeal and strength.
The conference also reinforced PXI’s breadth of capa-bilities by featuring a variety of PXI-based systems that addressed applications from the flight line to the depot. Continued development and introduction of new PXI prod-ucts for digital, RF, microwave, and lightwave applications has positioned PXI well for not just the mil-aero market but also for a range of other markets including the auto-motive, communications, industrial, and semiconductor market segments.
With continued market growth, and product innovation, it’s no surprise that both suppliers and users continue to adopt PXI as their platform of choice for test-and-measure-ment, data-acquisition, and process-control applications.
Loofie Gutterman is president and co-founder of Geotest—Marvin Test Systems.
PXI: One success story drives anotherBy Loofie Gutterman, Geotest—Marvin Test Systems
NI debuts switching systemDesigned for automated test systems with large numbers of channels, the NI SwitchBlock for PXI integrates with NI Switch Executive switch-man-agement software to provide a stream-lined option for switch configuration, routing, programming, and mainte-nance. NI SwitchBlock also includes NI Switch Health Center software, which automatically runs onboard di-agnostics that verify relay continuity and display relay count information.
The NI SwitchBlock comprises an expandable carrier that occupies four PXI slots and accommodates up to six relay cards. Engineers can use the car-rier’s integrated high-voltage analog bus to internally expand the relay cards into large matrices, with more than 2000 crosspoints in a single car-
rier. They can further expand these matrices with an NI SwitchBlock ex-pansion bridge, which extends a carri-er’s analog bus to additional carriers. Engineers can combine up to four car-riers to create internally routed matri-ces with as many as 8832 crosspoints in a single PXI chassis. www.ni.com.
Geotest expands FPGA capabilitiesGeotest’s FPGA-based GX3500 Flex-DIO 3U PXI cards, which can accom-modate custom or standard expansion boards that plug in directly as mezza-nine cards and do not require an addi-tional PXI slot, can now be configured with the company’s new GX3501, GX3509, GX3510, and GX3540 logic interface boards, which provide multi-channel interfaces for LVTTL, differ-ential TTL, MLVDS (multipoint-low-voltage differential signaling), and ECL (emitter-coupled logic) families,
respectively. The GX3501, GX3509, and GX3510 feature 80 I/O channels that are independently configurable as an input or output. The GX3540 fea-tures 20-input and 20-output ECL channels with a selectable termination to –2V or –5.2V.
Geotest has also introduced the GX3671 video generator board, which is based on the GX3500. The GX3671 supports the generation of 640x480 images for VGA, composite-video (NTSC and PAL), and S-video formats with 30 bits of color resolu-tion. In addition, the user has full ac-cess to the module’s FPGA core and can modify the video generator’s pa-rameters or create custom video sig-nals for video display or video proces-sor applications. The GX3671 is sup-plied with a video-interface module that supports a variety of video cables. Software for the module includes tools for importing and loading bitmap im-ages into the module’s video RAM. www.geotestinc.com.
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40 November 2010 • PX I TesT RePoRT w w w . t m w o r l d . c o m
At first, engineers wondered whether or not PXI could even
tackle RF testing. Then, it became just a question of what noise and frequency performance PXI could achieve. Now, the only questions are more like “how many channels do you want?”
“When the industry first came out with RF instruments in PXI,” said David Hall, RF product manager at National Instruments, “the naysayers pointed to electronic noise as a problem.”
Equally pessimistic assessments abounded about operating frequencies, bandwidth, and even the ability to fit useful functionality into the space con-straints of a PXI module. But all that has changed.
“There is no doubt that the industry has proven the feasibility of RF and microwave instruments in PXI,” said Larry DesJardin, GM of modular product operations at Agilent Technol-ogies. “In some areas, like noise and spurious-free dynamic range, PXI of-fers better specifications than that of many box instruments.”
Much of the drive to improve PXI’s RF performance, as well as the tech-nology that supported its implementa-tion, came from the wireless commu-nications industry. “The needs of wire-less LAN, WiMAX, MIMO, 3G, and LTE all pushed technology to new lev-els,” said Barry Hack, PXI product specialist at Aeroflex.
NI’s Hall also noted that innova-tions in the communications industry have led to smaller RF components, making it easier for vendors to imple-ment RF capability within the space constraints of PXI modules.
Thus, from simply being a rising contender in the RF arena a few years ago (Ref. 1), PXI has emerged as a dominant technology in RF test. A new emphasis on PXI from traditional box-instrument vendor Agilent Tech-nologies highlights this elevated stat-ure. The company released more than 40 new PXI products—many for
RF—at this year’s Autotestcon in Or-lando, FL, and has also upgraded its membership in the PXISA (PXI Sys-tems Alliance) to full Sponsor status.
RF specs meet current needsThe currently available RF products in PXI would astound those original nay-sayers. Pickering Interfaces has micro-wave switch modules with bandwidths to 65 GHz. Phase Matrix and Agilent both offer downconverters capable of operating at frequencies to 26.5 GHz. Agilent also offers a 1-GHz IF digitizer, a 3-GHz-to-10-GHz local oscillator, and other modules that combine with soft-ware to form the M9392A VSA (vector signal analyzer) with frequency coverage from 50 MHz to 26.5 GHz (Figure 1).
Noting that the technology needs that propelled PXI to achieve higher frequency and greater bandwidth are being met by the latest generations of PXI hardware, Aeroflex’s Hack com-mented that future developments in PXI may shift toward addressing other sys-tem attributes. “That is, of course, until another technology comes along with new demands,” he added.
One of the areas likely to see in-creased attention in PXI RF is channel density, according to NI’s Hall. “Today’s wireless handsets have multiple sig-nals—Bluetooth, GPS, WLAN, and so on—all on a single antenna,” he said, “so there is an increasing need for things like eight-port VNAs [vector net-work analyzers].”
Such needs are shifting PXI RF development from pure performance toward a focus on increasing the num-ber of ports and the density of chan-nels on modules. NI’s recently released PXIe-5630 6-GHz, two-port VNA, for instance, occupies only two slots (Fig-ure 2). Agilent has recently demon-strated a four-channel, phase-coherent microwave downconverter in a three-slot package.
To increase PXI channel capacity at the system level, as well as to improve
configurability, Agilent has introduced an 18-slot all-hybrid chassis. “Mixed cages are constrained in what you can do,” said DesJardin. “Eliminating the positioning constraints of those mixed-hybrid chassis can help simplify micro-wave RF, especially where cable loca-tions are critical. In some cases, a mixed chassis doesn’t have the right number and positioning of hybrid slots for the needed configuration.”
Channel limits loomThere may be a fundamental limit on how dense PXI channels and ports can become, however. “Moore’s Law is allowing us to get denser and denser,” said DesJardin, “but the tradeoff is increased power consump-tion on modules. The shielding needed for RF means that circuits are essen-tially enclosed in aluminum blocks, so we need low-power designs and very effective cooling.”
Hack noted that the need for shield-ing and isolation may also place physi-cal limits on how dense PXI RF mod-ules become. “There comes a point where you cannot compromise,” he said, and he added that connectors place constraints on what a PXI RF module can contain. “There is a limit on how many connectors can be use-fully employed on the front panel. Too many, and it becomes difficult to torque up the mating connector.”
But increasing channel density and capacity are not the only directions PXI RF development can follow. NI’s Hall, for instance, sees lower costs as a key goal. “As chips for WiFi and other wire-less networks became less expensive,
PXI RF development shifts focusBy Richard A. Quinnell, Contributing Technical Editor
Fig. 1 Agilent’s recent push into pXI, including the release of the M9392A 26.5-gHz VsA, confirms that pXI has proven itself as an RF test technology. Cour tesy o f Ag i len t Techno log ies .
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they have found applications in other technologies, such as smart utility me-ters,” he said. “That means there are a lot more engineers who need to per-form RF testing, and they are going to want lower-cost instruments.”
The cost reductions will arise in part from the modularity inherent in PXI, the benefits of which are one of the
fundamental messages of PXI, accord-ing to Hack. “Pay for what you need, not for what you get in the box.” As an example, Hack pointed to the test of dynamic frequency selection in wireless routers. “With PXI, it [dynamic-fre-quency-selection test] becomes a single eight-slot hand-carried test solution. The equivalent in GPIB or LXI would
Fig. 2 The rise of multichannel and multiport capabilities, such as from this two-port VNA from National Instruments, represents the next di-rection for pXI RF development. Cour tesy o f Na t iona l Ins t ruments .
need at least six different pieces of equipment commanding a price around three times that of the PXI solution.”
Processing power risesAnother trend in PXI RF, especially with growing availability of FPGA boards for PXI (Ref. 2), is increasing processing power. “Signal processing is of great importance in RF,” said Hall, “and PXI is bringing more and more processing to test that was not avail-able to the traditional RF engineer. The peer-to-peer streaming available with PXI Express, for instance, lets you use an RF instrument as though it had its own onboard FPGA, allowing such functions as real-time spectrum analyz-ers and on-the-fly demodulation.” Hack pointed out that, unlike with box in-struments, this processing power is under the user’s control, not the test equipment manufacturer’s.
Enhanced processing power is an area where PXI RF is likely to consis-tently stay a step ahead of box instru-ments. “Box instruments tend to have processors inside with compute power that is typically two or more years old,” said Hack. “They launch with the same processing power they had when they were first being developed. PXI instru-ments can launch with whatever pro-cessing power is available today.”
PXI RF is also staying ahead of box instruments in addressing new applica-tion needs. Streaming digitized RF sig-
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nals to storage, for instance, has been available for many years according to Hack. “What’s happened with PXI,” he said, “is that those type systems have been miniaturized further than benchtop equipment could have ever taken them, with field portable sys-tems replacing vehicle-mounted sys-tems of the past.” Such size reduction, he added, can be a driving factor for adoption of RF streaming in military and intelligence applications.
Boxes retain some advantagesBox instruments do retain an advantage over PXI for RF, according to Agilent’s DesJardin, in their ease-of-use on the bench, especially when engineers need to make pure parametric measurements. Here, the flexibility that PXI offers cre-ates an obstacle, as it requires users to configure the system and load a pro-gram before running a test. Box instru-ments, DesJardin pointed out, are ready to be used as soon as they power up.
While PXI is continually making advances in the simplification of such configuration and programming, these needs can still be a barrier for many test engineers. “Customers quite often need significant support to understand and grasp the concepts behind this advanced technology,” said Hack. “I still get asked for the GPIB address of PXI instruments.”
Vendors are, however, increasingly providing such support in terms of de-velopment tools and software packages for RF test capability. Agilent’s new M9392A VSA, for instance, has the support of the company’s 89601A VSA software package, providing users with immediate access to both general-pur-pose and standards-based demodulation and signal-analysis functions. When Aeroflex released the 3061 multiport RF combiner earlier this year, the com-pany also updated its WLAN Measure-ment Suite software to take advantage of the combiner’s MIMO capabilities.
The increasing software support as well as the achievement of performance levels that satisfy the needs of communi-cations test has placed PXI RF on an equal footing with box instruments for most applications. And where box in-struments still offer a technical edge, PXI is almost certain to quickly follow. “There is nothing in traditional instru-mentation that cannot be done in PXI,” said NI’s Hall, “and the transfer of tech-nology from box to PXI is accelerating.”
With performance no longer a major issue, then, PXI RF developers are free to focus their development efforts on characteristics such as cost, channel density, and system capacity.
REFERENCEs1. Quinnell, Richard A., “PXI makes inroads into RF test.” PXI Test Report, Test & Measurement World, November 2007. www.tmworld.com/2007_11.
2. Quinnell, Richard A., “User-configurable FPGA mod-ules boost PXI system versatility,” PXI Test Report, Test & Measurement World, May 2010. www.tmworld.com/2010_05.
