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Communications Test Equipment Evolves In Hard Times

Despite a sluggish economy, communications-centric test-and-measurement equipment continues to get better, faster, and cheaper

By Alex Mendelsohn, Senior Technical Editor

Since the calendar clicked into the new millennium, more than 600 major public companies, with hundreds of billions of dollars in assets, have gone belly up. Over the same period, ten million Americans have lost their jobs. One out of every 69 households filed for bankruptcy last year, and this year's predictions are worse.

What's this got to do with the long- and short-haul communications test industry? In a word: everything.

Consumerism is key to growth, but consumers just aren't wildly spending. Though sales of videophones, MP3 players, and some personal communications widgets are reasonably brisk, the volume just isn't there. Not even so much as one killer application has materialized.

On Wall Street, high-tech investors are holding their cards tight to their vests. Venture capital has all but evaporated.

Technology Marches On

Although the outlook is less than rosy, test equipment makers aren't letting grass grow under their feet. Technology marches on. Product development remains aggressive. A thrust is to lower the cost of test.

"We're expecting a turnaround," avows Tektronix (Beaverton, Oregon) Worldwide Marketing Manager Steve Bannon, "and we'll be ready when the economy recovers. Right now however, we're offering test gear that's cost-effective."

Bannon points to his company's TLA5000 Series logic analyzers. Debuting in July, one of these mid-range box-level 32-channel products is actually priced at an unheard of $9200. Even at that rock bottom price the analyzer touts 500-ps deep-memory timing capability, simultaneously with 125-ps acquisition speed.

Frustrated Plans

Not every pundit is as sanguine as Tek's Bannon. "Test vendors are hard-pressed to sell," note Frost & Sullivan (New York, New York) analysts Jessy Cavazos and Sailaja Tennati. "Their customers are re-evaluating their expansion plans. Network equipment manufacturers and service providers aren't buying right now."

In a report dubbed Opportunity Analysis of the Telecommunication and Data Communication Test Equipment Market, Frost & Sullivan concludes that engineering firms are waiting until capital markets improve. In the light of excess inventories and declining sales, new purchases will be rare.

When profits go up and inventory goes down, things may pick up. Right now though, the compound annual growth rate (CAGR) for the test equipment market is stagnant at just a tenth of a percent. According to Frost & Sullivan, total communications test market revenues did total $2 billion last year, but with a growth rate of a negative 21%.

The economic downturn does have a flip side, however. It's a catalyst for the development of state-of-the-art communications test-and-measurement hardware and software. Automated configuration programs, hardware modularity and reconfigurability, standard operating systems, networking, and user-friendly human interfaces are the rule.

Despite a likely moderate dip in revenues during the short term before any recovery, as Tek's Bannon notes, vendors are dangling a tantalizing array of wares under the noses of potential buyers. What's more, product makers are tackling the issues of cost-of-ownership and upgradability head on. Regardless of these juicy test equipment carrots, Cavazos and Tennati confirm that reduced capital expenditures on the part of OEMs is limiting demand. "Struggling test equipment vendors are pinning their hopes on evolving network technologies for market revival," they conclude.

"With the growing need for test equipment makers to continuously innovate, re-position, and provide modular approaches," they point out, "the demand for testing equipment will pick up as new network technologies evolve."

With a focus on both wired and wireless communications, everybody's waiting for that phase of the recovery. When and if it happens, industry watchers predict that the market for communications test gear could show a reasonably healthy CAGR of 3.5% or more. The convergence of voice, video, and data, and especially the demand for systems to handle increasing Internet and intranet traffic, should fuel demand for new technology-capable test equipment.

Rent, Lease, or Homebrew

Right now though, there's a trend for communications engineering firms to purchase second-hand equipment. Others have opted to develop in-house approaches instead of purchasing. Or, they're making do with existing, and in some cases, obsolete test schemes.

Renting test equipment is also popular. Although outright purchase of communications test gear ensures that you'll get the latest and greatest technology, renting---especially month-by-month---can keep cash outlays to a minimum. The cost of periodic re-calibration is also sidestepped in some cases, as that's typically an integral part of a rental deal.

If your needs are longer term, and you want the newest test equipment, leasing---with an option to buy later---may be more viable. Leasing can also let you get your hands on that whiz-bang $50,000 storage scope that you've absolutely got to have to properly see those eye diagrams and evaluate jitter noise factor.

Standards Set The Pace

In spite of penny-pinched OEM budgets, evolving definitions for high-bandwidth applications and protocols is compelling test equipment makers to develop new communications test products. The goal is to give OEMs cost-effective test equipment they can use during debug cycles, for functional tests, and to ensure that products are compliant with standards.

For wired communications, vendors are slating new products for an alphabet soup of emerging and converging technologies. These include the likes of xDSL (digital subscriber line) Internet access gear and optical dense wavelength division multiplexing systems, as well as next-generation Synchronous Optical Network/Synchronous Digital Hierarchy (SONET/SDH) equipment.

Other evolutionary technologies include Gigabit Ethernet (10GbE), Gbit Fibre Channel (10GFE), and Voice over Internet Protocol (VoIP). The emergence of Resilient Packet Ring (RPR), and Asynchronous Transfer Mode over Multi-Protocol Label Switching (ATMoMPLS) is also fueling the development of new types of test equipment in anticipation of a general industry up-tick.

Lanes of I/O

High-speed serial technologies abound in the datacomm domain as well. Gbit/s serializer and de-serializer (SerDes) chips are being designed-in to establish parallel "lanes" of lightning fast serial I/O for board-to-board and chip-to-chip communications.

Even as system developers adopt serial datastream technologies such as 480-Mbit/s Universal Serial Bus (USB) v2.0, InfiniBand, and Fibre Channel, additional PC-centric technologies are vying for prominence. These include the likes of PCI Express, Serial ATA, RapidIO, and DVI. Other high performance approaches are in the wings, such as 10 Gbit Attachment Unit Interface for copper and fiber (10GBE-XAUI and 10GFC-XAUI).

Validation and pass/fail analog compliance testing are just a few of the elements for successful OEM implementation of these copper and optical technologies. Affordability is another. A new test tool from FcBay (Foster City, Calif.) is an example of a moderate cost system that can be used by designers and technicians, as well as system integrators crafting Fibre Channel systems. It costs as little as $9800.

Priced at about $9800, FcBay's Fibre Channel analyzer provides a Windows-based analog-like display that visually meters system parameters.

FcBay's Model FCB-2020-xL is a portable Windows-hosted multi-channel instrument. It captures and analyzes Fibre Channel traffic, supporting both 1-Gbit/s and 2-Gbit/s implementations. It also provides hot-pluggable interfaces for copper as well as multi- and single-mode optical waveguides.

The FCB-2020-xL lets you simultaneously analyze four Fibre Channel ports in realtime, and trigger on user-defined patterns up to 32 words deep. The box will also trigger on low-level errors such as illegal codes, CRC and running disparity errors, or loss of sync or signal.

Communicating over USB, FcBay's system is equipped with large capture buffers and an FPGA-based data-processing engine. "The hardware handles frame triggering, payload filtering, and realtime statistics while the analyzer is in record mode," explains company founder Peter Bolech. "Trace searching and post-processing occurs while the analyzer is in its display mode."

Vital Jitter Tests

At the physical layer, signal amplitude, timing and, especially, jitter measurements, are critical at Gbit speeds. As such, equipment suppliers are offering low-jitter noise-floor oscilloscopes, supporting a variety of communications clock recovery schemes, and with special eye pattern mask features.

Some scopes measure jitter noise factor over many acquisition cycles. Others, such as Tektronix's scopes equipped with the company's RT-Eye analysis software, build an eye pattern from just one acquisition cycle, with DSP used to recover the clock and align the pattern.

These scopes also demand wideband probes for non-intrusive tapping of both single-ended and differential transmission lines. Buses communicating at very high speeds can't tolerate probes with very much capacitive reactance, so scope makers are supplying probing schemes with just picofarads of parasitic capacitance.

Bandwidth to the Probe Tip

Johnnie Hancock, Oscilloscope Product Manager at Agilent Technologies (Colorado Springs, Colo.), points to his company's InfiniiMax probes. These complement the company's Infiniium line of digital storage oscilloscopes.

Agilent's low-C oscilloscope probes can tap differential signals on GHz-speed signal lines.

Hancock emphasizes how a limited-bandwidth probe can cramp the performance of a high-bandwidth scope. He also explains how some active-probes exhibit in-band resonances that can distort signals. "A resonant condition can load down a circuit under test if the probe acts as a low impedance," he notes.

"Some active probes can only achieve their specified bandwidth in conjunction with fixtures that are designed into a target system. But, it's impractical to expect that you'll know in advance where you'll need to make a measurement. You may not know where to put a permanent probe connector or fixture attachment point on a circuit board when you're doing PCB layout."

A controlled-impedance balanced transmission-line probe exhibits a flat frequency response, eliminating resonant loading. Captured traces reveal the effect of a probe's input-impedance on a 1.2-GHz clock signal. The upper trace shows the effect of probe loading. The lower trace reveals negligible loading. Traces courtesy Agilent Technologies.

In line with Hancock's remarks, Agilent's controlled-impedance transmission-line probes exhibit essentially flat frequency-responses, and virtually no loading. "They let you use an oscilloscope's entire bandwidth," contends Hancock, "without being limited to measuring only low-impedance 50-ohm transmission lines, or using passive-resistive voltage dividers that can introduce errors of their own or load a circuit down."

Acquiring High-Speed Signals

Agilent is only one company competing for mind share in today's meager marketplace. At least a dozen other T&M companies are offering high-speed scopes and signal analyzers designed for looking at fast edges and high-speed signals.

Oscilloscope maker LeCroy (Chestnut Ridge, New York), for one, recently launched two new scopes for communications applications. "There's no end in sight to the need for faster data communications," avows Tom Reslewic, the company's president and CEO. "As data rates increase, EEs must have the capability to analyze increasingly complicated signals."

With 1-GHz and 3-GHz bandwidths, LeCroy's WavePro 7100 and WavePro 7300 instruments rely on patented software, state-of-the-art silicon-germanium (SiGe) amplifiers and A/D converters, plus a unique signal-path processing architecture the company calls X-Stream Technology.

The latter is also used in the company's SDA Series realtime serial digital analyzers to process eye patterns. X-Stream lets you insert customized, proprietary, or even classified measurement algorithms directly into a scope's signal processing path.

X-Stream Technology is key to providing high throughput on long data arrays. The front end of an X-Stream Technology system may start with the output of a 20 Gsample/s A/D converter on each channel, for example. Since each data sample is eight bits, a stream of 20 Gbytes/s is generated. Each of four channels streams this data in realtime into CMOS memory that accepts up to 48 million points of acquisition.

This data is then packetized and transferred in a streaming mode using dual data buses on the instrument's CPU board. At that point, the operating system optimizes the possibility that analysis algorithms and data packets are simultaneously resident in cache so that ultra-fast calculations can be performed. Moreover, the technique works so that a long complex waveform can be processed while the next signal is flowing through the front-end of the streaming architecture.

The system's algorithms enable data packets, and the analysis routines for performing measurements on those packets, to be simultaneously resident in cache. LeCroy claims this permits analysis to be conducted on the packetized data at rates that are ten to 100 times faster than earlier techniques that relied on moving data to a microprocessor from RAM.

As a user, you can also create custom measurements using packages such as The MathWorks' (Natick, Mass.) popular MatLab package, or other packages such as Mathcad, Excel spreadsheets, or VisualBASIC scripts. Using these, you can insert math functions or parameter measurements directly into the processing stream. This lets you generate histograms, parameter tracks, FFT (fast Fourier transform), or persistence displays even when doing customized analysis.

On the hardware side, the SiGe-equipped WavePro boxes tout 10-Gsample/s sampling rates on each of four channels. That's sufficient to acquire up to 24 million points in a 4-channel mode, or the whopping 48 million points using dual channels. With deep memory and 10:1 over-sampling, it's clear that these instruments can meet the demands imposed by ultra-fast datacomm technologies.

Like many of their competitors, LeCroy's boxes come bundled with human-oriented software to enhance datastream analysis. A jitter analysis package, for example, lets you measure a variety of high-speed timing parameters, including period, width, and cycle-to-cycle characteristics. In the LeCroy scopes, jitter findings are presented as statistics, histograms, or time-domain tracks.

LeCroy also offers a version of the popular Amherst Associates jitter program. This option relies on one of its WavePro scope's ultra-stable hardware, with its 5-ppm clocking stability and a 1-ps jitter noise floor.

Like LeCroy's oscilloscopes, some other manufacturer's scopes also let you run FFTs to get frequency-domain spectral views of a signal's jitter source. An FFT can let you look for things such as harmonic content.

Such products illustrate how vendors are meeting communications test challenges head on. These products can acquire signals at Gbit speeds as they trigger on things such as packet attributes, while filtering and searching large acquired data sets. These instruments then display their voluminous findings in a human-oriented manner.

Mixed Signals

Mixed-signal and RF analysis is also an element of successful communications equipment design. Agilent's Infiniium family of 600-MHz to 1-GHz mixed-signal oscilloscopes, for example, target designers working with communications systems that mix signal types and speeds. The Agilent 54830-Series Infiniium scopes let you trigger on, and view, up to 20 time-aligned signals on one instrument.

What's more, Agilent's deep memory approach enables observation of long serial data streams with high resolution. The company's scopes can find details buried in high-speed waveforms. With its long time-capture feature, Agilent's 58430D Infiniium scope, for example, can help debug systems by letting you see details in complex modulated signals. You can even discover anomalies in the absence of a known or good trigger event.

There's also a USB v2.0 option that enables pre-compliance testing of earlier low-speed as well as full-speed USB devices; the scopes actually run certified USB scripts using MatLab. Communication mask testing options are also available to ensure that designs conform to other industry standards. Agilent's 54854A and 54855A scopes, both 20-Gsample/s instruments, also run a version of Microsoft Windows operating system, as do a preponderance of new instruments offered by almost every T&M vendor these days.

Agilent's '854A and '855A, for example, permit you to launch third-party applications. You can run software packages such as Excel spreadsheets, or engineering applications such as National Instruments' (Austin, Texas) LabVIEW, Agilent's VEE, or The MathWorks' MatLab.

You can also configure an Infiniium scope with Web connectivity. Web-ready scopes like Agilent's let you do things such as send an e-mail on a trigger condition, or drive the instrument remotely through your favorite browser.

When equipped with a $4000 jitter analysis option, both the '854A and the '855A can make cycle-to-cycle jitter measurements, too, as well as measure n-cycle and period jitter. The software also lets you measure time-interval errors and setup-and-hold times, creating clearly decipherable histograms, spectrum, and trend displays.

Some instruments can also help reduce cost of ownership by integrating functions associated with other instruments. Some Infiniiums, for example, pack integrated 16-channel logic timing analyzer functions.

The Wireless Rage

Industry pundits also optimistically point to the wireless arena, where developments and standards definitions continue unabated, too. Even as IEEE-802.11n variants garner attention at the WiFi center stage at 2.4-GHz and 5-GHz, Bluetooth and ZigBee demand their share of developers' attention.

Sure, it's no news that the adoption of Bluetooth short-range wireless in the unlicensed 2.4-GHz ISM (Industrial, Scientific, Medical) band is slow. It's not just the depressed business environment either. Regardless of hype, Bluetooth just hasn't caught on with consumers.

Yet, in spite of that, Bluetooth proponents cry "damn the torpedoes," as they press ahead. In fact, the Bluetooth Special Interest Group is slated to ratify v1.2 of the spec before year's end. That's not surprising when you look at the membership list of the Bluetooth club. The SIG Big Boys include the likes of Microsoft, Nokia, Ericsson, 3Com, Lucent, IBM, Intel, Motorola, and Toshiba, plus 2500 other SIG participants.

No wonder large T&M companies, as well as smaller firms, such as Computer Access Technology Corp. (Santa Clara, Calif.), are releasing v1.2 BlueTooth test products. CATC's Tracer/Trainer system, for example, is now a top-of-the-line extension to the company's Merlin Bluetooth analyzer family.

CATC's latest analyzer provides the capabilities of the company's earlier Bluetooth design and verification systems, plus lots of new features. The product now melds a protocol analyzer and an exerciser into a single box that CATC calls its Universal Protocol Analyzer System. When equipped with appropriate plug-in modules, the UPAS comprises an integrated environment for testing as well as verification. Significantly, it provides an upgrade path to future releases of the Bluetooth spec.

Another company that's hot on Bluetooth is Japan-based Advantest. Its North American sales entity, Advantest America Measuring Solutions (Santa Clara, Calif.), just launched a new feature-rich RF communications tester. Advantest is known for its automatic test equipment, primarily offering ATE for semiconductor testing of logic, memory, mixed-signal and RF devices. Its new Model R4870 Bluetooth test set is a bit of a departure for the company, representing a bench-level piece of communications test equipment.

The R4870's testing can also be automated. With its ability to do Bluetooth loopback testing using an embedded host interface that handshakes with a PC across nothing more than an RS-232 serial line, the R4870 can check things such as receiver sensitivity and bit error rate (BER).

The R4870 can also exercise higher levels of the Bluetooth protocol. It implements so-called Blue Unit Test Cases, which are part of the Bluetooth SIG standards for evaluating interoperability. The system accommodates this by executing a connection, which is a sure way to feel confident that a product-under-test is working properly. Finally, the Advantest box can communicate with other test equipment in a rack, in an IEEE-488 General Purpose Interface Bus (GPIB) environment.

Cellphones Are Everywhere

In spite of deployment lethargy, 2.5G, 3G, and even fourth generation (4G) cellular technologies are under development, and international standards bodies are hammering out the details. Just this month Japan-based NTT DoCoMo announced the formation of DoCoMo Communications Laboratories Beijing Co. Ltd. The company's goal is to develop 4G cellphones, and beyond. The subsidiary is already capitalized at more than $5 million, and will be operational before year's end.

Tektronix' newest digital-cellular radio analyzer combines features you'd expect in a conventional RF spectrum analyzer, but adds dedicated Layer 1 digital modulation test features. Tek's WCA200A displays W-CDMA up- and downlinks, as well as nonstandard signals.

There's also lots of R&D focusing on other wideband digital transmission schemes for delivering everything from broadcast radio to Internet access. Communications test equipment makers are addressing the near-future needs of OEMs adopting and integrating these RF technologies, regardless of whether the protocols are finalized or not. As product complexity increases, verification at the baseband level is increasingly important, as much of the intelligence in transceiver design resides at baseband these days.

Verifying performance at early stages of an RF-based design is more compelling than ever for OEMs that want to avoid costly rework after system integration. OEMs can choose from myriad products related to RF testing, evaluation, and conformance.

Products include cellular protocol simulators, multi-path signal simulators, handheld analyzers, LCR meters, BER meters, RF power meters, spectrum analyzers, and modulation analyzers, to name just a few.

The Willtek Communications 9100 Series handheld spectrum analyzer, priced well below $10,000, extends the upper frequency range of this breed of nomadic instrumentation to 4 GHz.

Agilent Technologies, for example, has just rolled out what it bills as the industry's first spectrum analyzer that provides an 80-MHz window of demodulation bandwidth. The company's Model PSA-80BW touts an 8-second capture memory, too. That's useful for observing spectra associated with multi-carrier power amplifiers (MCPAs) and communications satellite signals, as well as more esoteric systems such as radars.

The extremely wide bandwidth and long capture period of the PSA-80BW promises thorough signal characterization as well as digital predistortion, or DPD, measurements. The PSA-80BW provides up to 20-GHz frequency coverage, 0.1-dB amplitude flatness, and 0.7-degree phase flatness. In addition to specs like those, the instrument offers an optional 1.2 Gbyte (768 Msample) capture memory to ensure full bandwidth capture at the instrument's maximum sample rate.

A key selling point is that the PSA-80BW wide-bandwidth vector spectrum analyzer essentially sidesteps the need to design your own wideband test equipment. Agilent makes the case for focusing on next-generation RF design for products, not designing test suite hardware and software.

Factory Floor Connectivity

OEMs are also seeking cost-effective test equipment that can be used for functional and compliance testing in production. Increasingly, OEMs want test equipment for both laboratory work and the factory floor. Networking is key. For vendors, connectivity is now a hot selling point.

In an annual survey conducted by test equipment maker Keithley Instruments (Cleveland, Ohio), OEMs reported that they're no longer relying on simple RS-232 connectivity, or even the venerable IEEE-488 GPIB as much as they did in the past. In its poll, Keithley found that the number of implementers choosing GPIB dropped from 53% to 42% in a single year.

Keithley reports show that even IEEE-1394 FireWire is growing in significance as a test automation protocol of choice. As GPIB wanes, high-speed Ethernet, and especially plug-and-play USB is growing in popularity. The use of USB for placing test equipment on a network is also dramatically increasing.

In addition to plug-and-play simplicity, OEMs are looking for better, and bug-free, test software. "Workforces have been slashed," contends Agilent R&D Planning Manager Dave Karlin. "Broader demands on existing engineering staff means that, in some cases, non-engineering people are being asked to perform traditional engineering roles. But test system set-up requires instrument base knowledge and sometimes lots of intellectual property.

"Most T&M users heretofore relied on T&M-specific software and I/O technologies. As a result, EEs developing applications to control test equipment were using languages and development environments unique to the industry. This contrasts with the computer world, where general-purpose standard programming languages are used.

"The use of T&M-specific I/O has made the process of connecting T&M instruments expensive, time-consuming and frustrating," adds Karlin. "The widespread use of proprietary T&M software and hardware complicates the creation of new test systems."

Addressing that conundrum, Agilent is rolling out what it calls a test automation kit. Priced at less than $2000, the company claims the kit will expedite the connection and verification of disparate test equipment (albeit for low-frequency applications), including T&M components from vendors other than Agilent.

An alternative to the popular rack-and-stack architecture used for most test suites, Agilent's test automation kit includes a USB/GPIB converter pod for I/O connections. The converter eliminates the need to install a GPIB card into a host PC controller.

The kit's Test Express software loads drivers, and identifies and configures typical test systems in environments running Agilent VEE, Microsoft C, Excel, VisualBASIC6 and VB Net, and National Instruments' LabVIEW. A special USB/GPIB converter module gives you plug-and-play I/O, with no need to disassemble a PC to get at its PCI bus slots.

"What used to take two to three weeks to set up, can now be done by a technician in an hour or so," claims Karlin. "The Test Automation Kit also includes a test module to enable quick verification of a test system."

Wares like these make it clear that despite the severe downturn, T&M product development remains aggressive. The industry consensus is that users and vendors will both profit as soon as the economic picture gets healthier.

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