5 Things That Will Drive Test in 2015

Feature articles | January 18, 2015

By eeNews Europe

Wireless
You’ve probably noticed that everything seems to be going wireless. Thus, the deployment of LTE and LTE-A on cellular networks, plus 802.11ac Wi-Fi, Bluetooth Low Energy, and NFC on local networks will drive test activities in 2015.

"eMBMS (evolved Multimedia Broadcast and Multicast Service) is the enabling technology for LTE Broadcast services such as LTE Multicast," said Richard Bellairs, product marketing manager at Anritsu. "Developers of wireless chipsets and devices are in a competitive race to support eMBMS and test equipment must address early development, conformance, acceptance, and regulatory issues. Regression tests, backward compatibility, and other validations must be made to ensure the end-to-end user performance meets specifications."

As cellular and short-range wireless technologies converge, test will be a part of what brings it all together. "Expect to see short-range and low-power technologies such as WLAN, Bluetooth Low Energy, ZigBee, and NFC connect small sensors to devices, said Mark Wallace of Keysight Technologies. "Those connections will create HetNets (Heterogeneous Networks)." The integration of those technologies will require interoperability testing with 3G and 4G (LTE and LTE-Advanced) technologies." Eventually, 5G should bring it all together, but that’s yet to be defined. Wallace added "5G will bring together wireless technologies with networks to provide consumers with access that was once only expected from wired connections."

Everywhere you turn, you hear about our insatiable appetite for mobile data. That appetite will continue to push for more bandwidth than is available. James Kimery, director of Marketing for RF, Communications, and Software Defined Radio (SDR) at National Instruments, notes that technologies coming online will ease the inevitable data crunch. "Wireless service providers plan to furiously upgrade their networks to 4G LTE, LTE-A, and beyond, adopting new innovations including MIMO (multiple input multiple output) and carrier aggregation. But, the current technology trajectory still produces a capacity slope more flat than the demand line. As a result, new wireless technologies that will be part of a 5G network are now in the research stage."

High-speed serial data

All the data that goes to mobile and wired devices comes from datacenters and is then carried over high-speed electrical and optical serial links to and from their destinations. Those links stress the limits of transmitters, receivers, interconnects, PCBs, and anything else along the way. That’s the focus of DesignCon 2015.

100 Gbit/s serial links consisting of 28 Gbit/s and 32 Gbit/s lanes have been the subject of DesignCon for several years. Now, talk of 56 Gbit/s lanes is erupting. The industry has yet to settle on a modulation form (NRZ or PAM4) so right now, both are in development for 56 Gbit/s links. Both of these modulations will be subject to BER (bit-error rate or bit-error ratio) tests.

"BERTS (BER testers) will have to measure at speeds such as 28G/32G, while having the scalability to support higher data rates such as 56G NRZ or 56G PAM4," said Hiroshi Goto, Business Development Manager at Anritsu and a frequent contributor at DesignCon. "BERTS will have to provide pre-emphasis and de-emphasis on multiple channels to conduct cross-talk tests. Engineers will need to inject accurate and repeatable jitter into serial data streams for jitter-tolerance tests."

Not only do data rates increase, but the amplitudes of digital signals decrease, making signal integrity even more of an issue. "These changes are introducing stringent requirements for transmitter, receiver and channel tests. Distortions such as jitter, ISI (intersymbol interference), and noise have to be carefully accounted. Test engineers must be sure they are capturing and measuring the true signals, as opposed to wondering if what they are seeing is just an artifact of the test setup," said Keysight’s Wallace."

Chris Loberg, Senior Technical Marketing Manager at Tektronix noted that researchers are already starting work on 400 Gbit/s and 1 Tbit/s optical links. They will further push the limits of signal margins in eye diagrams and as well as BER performance.

400 Gbit/s fiber-optic network tests are already underway as network providers scramble to find ways to drive more content through their backbones. "Imagine the demand for high-speed networking once Google Fiber and other competitive services begin providing 1 Gbit/s connections to the home," Loberg said. "To meet that need, a new generation of chips, controllers and modules will all need to be characterized and validated."

In addition to characterizing and validating ICs, engineers will need to characterize transmission channels: PCB traces, connectors, cables, and other components. That should drive the need for ever faster oscilloscopes and higher-frequency network analyzers. 2015 could also be the year that optics make a deeper penetration into silicon, PCBs, and cables. Several papers will cover optics at DesignCon 2015 including a panel discussion, Will the Optical Backplane ever happen?

Source: TTM Technologies

Automotive
Wireless and wired serial communications are invading today’s vehicles and are "driving" the need for test. BroadR-Reach Ethernet for cars and MOST150 are two communications technologies moving into today’s cars. As Keysight’s Mark Wallace explained, "New entertainment systems will connect more devices by wireless technologies such as Bluetooth, and WiFi. The embedded cellular technologies are also playing more roles for eCall (car will automatically call an emergency center when a serious accident occurs). Services such as in-car hot spots that convert 3G/4G cellular signals into Wi-Fi, plus location-based advanced navigation services, are coming online."

An automotive communications network. Source: Keysight Technologies

Instrument user interfaces
In Knobs and Buttons Are Toast, Long Live the Pinch, I noted how more powerful PCs, coupled with smartphones and tablets, are changing the way engineers control test equipment. The use of PCs as instrument interfaces, while nothing new, made numerous appearances in 2014, particularly in RF test equipment. Expect more in 2015. Why? Because PCs are powerful enough to relieve test instruments from burdensome signal processing.

The FM broadcast band displayed using persistence mode with the Signal Hound BB60C spectrum analyzer.

"The growing mainstream adoption of PC and tablet-compatible test and measurement instruments is a reflection of a broader trend of software-based things," said Chris Delvizis, senior product manager at National Instruments. "PCs and mobile devices have evolved into centralized platforms that provide a common user interface and interoperability between devices and tasks. For engineers, the interoperability between instrumentation and other tools within their workflow means increased ease-of-use, convenience, and productivity."

Delvizis also noted "Today’s engineers are extremely tech savvy and are entering the workplace having grown up using computing devices." The "tech savvy" engineers are bringing about a change in how engineers gain access to their test instruments. Alan Tong managing director at USB oscilloscope maker Pico Technology noted that, although Windows has been the dominant operating system on engineering benches and for controlling test equipment, there’s a shift in the air. "A reluctance to upgrade to Windows 8 and greater familiarity of alternatives," he said, "is resulting in increasing demands to run design tools and test equipment on multiple platforms such as Linux, Android, and Mac OS X."

I’ll second Tong on the reluctance to adopt Windows 8. Hopefully, Windows 10 will be the worthy successor to Windows 7. Indeed, I bought my first Windows 7 computer in 2014 and will likely buy another one or two this year. I even bought my first Mac in 2014.

Power-integrity problems are usually associated with high-speed digital systems. When devices switch, they draw high instantaneous current that, because of inductance on PCB planes and traces, can pull down a power rail. That’s certainly going to get worse as data rates go ever higher. Steve Sandler, Managing Director at Picotest, will deliver a tutorial at DesignCon 2015 on how power integrity is becoming every electronic designer’s problem.

Not only have signals taken on microwave characteristics, but now power devices can switch that quickly. "GaN IGallium Nitride) power devices can switch at rates of 300 V/ns and it could replace silicon in power devices," said Sandler. The figure below shows that GaN devices can have rise times as short as 20 ps. Having power that switches significantly faster will certainly affect power-supply design plus power-delivery systems.