Connected devices mandate RF, power test

Hall added, “NI uniquely targets the entire value chain of wireless devices—from prototyping the wireless standard to final production test of the end device. In fact, in the same timeframe that test engineers are using PXI to test 4G RFICs and completed mobile devices, leading researchers are using NI software-defined radio technologies to prototype for the next generation of wireless or 5G.”

Hall elaborated on NI’s platform-based approach, which applies a common measurement science across a product’s life cycle. “Particularly for RFIC test, the use of a common platform greatly improves issues with measurement correlation and reduces time to market,” he said. “With NI’s platform, engineers developing RFICs can use the same PXI products from R&D through manufacturing test. In this scenario, the NI vector signal transceiver and measurement software that an engineer might use in the R&D lab are identical to the hardware and software inside the STS used for high-speed production test.”

From lab to maintenance

Keysight Technologies products extend from the lab to beyond manufacturing. Martha Zemede, 5G and IoT outbound marketing lead for the Wireless Cross-Divisional Initiative, said, “Keysight provides a broad range of tools that accelerates a product’s progression from the lab to the production floor and, when needed, on to installation and maintenance. Our offering includes design and simulation software as well as standalone instrumentation, wireless test sets, and modular instruments.”

She added. “Two of our most recent solutions and configurations that are well suited to the development and manufacturing of IoT devices are the M9420A VXT PXIe vector transceiver and the E6640A EXM wireless test set.”

She described the M9420A VXT PXIe vector transceiver as “… a fast, flexible solution for testing connected devices from product development to design validation to manufacturing. The modular form factor delivers the measurement speed and flexibility necessary to create custom solutions that can reduce an entire rack of traditional test equipment into a single, 4U chassis with the additional advantage of the speed that PXI provides.”

The EXM wireless test set is a one-box unit for testing connected devices. “In IoT, the economics of design validation and high-volume manufacturing demand a consistent understanding of device performance from early prototype evaluation to manufacturing,” Zemede said. “The EXM offers the ultimate in scalability and port density as well as the broadest multiformat coverage for cost-effective testing of IoT devices.”

Zemede is responsible for end-to-end marketing programs and works closely with marketing stakeholders across Keysight’s product and software divisions as well as regional marketing organizations.

Anritsu serves connected-devices applications in the area of test design, development, product test, conformance, factory test, and repair, according to Jay Torgerson, Anritsu business development manager for the Internet of Things. “We offer a full line of test equipment for the cellular, Bluetooth, WLAN, and Zigbee technologies,” he said.

He added, “Anritsu’s portfolio of IoT test solutions includes the MT8870A universal wireless test set, the MS2830A spectrum/signal analyzer, the MT8852B Bluetooth test set, the MD8475A signaling tester, the MT8820C and MT8821C radio communication analyzers, and the MD8430A/RTD signaling tester.”

“Our broad portfolio of test solutions allows Anritsu to support all stages of the IoT life cycle from R&D and characterization through manufacturing all the way to repair,” Torgerson said. “The measurement support correlation comes from the consistent accuracy of all the measurements. Therefore, if the same measurement was taken on different equipment, it will give a similar result.”

Physical-layer test

Matt Maxwell, product marketing engineer for the source analyzer product line at Tektronix, said the company offers the RSA306 USB spectrum analyzer running with SignalVu-PC software. The instrument, he said, covers RF measurements for physical-layer testing of ZigBee, Bluetooth, and WLAN devices and serves as a general-purpose real-time spectrum analyzer. “The RSA306 has a breakthrough form factor,” he said. “Weighing about 1.2 pounds, it is a full-featured spectrum analyzer the size of a paperback book. SignalVu-PC is the Windows-based software that controls and powers the RSA306 when connected to a PC. Unlike other low-cost spectrum analyzers, SignalVu-PC software offers full featured spectrum and signal analysis features, including wireless standards applications, vector signal analysis, and more.”

He continued that the instrument plus software combination “… can give R&D engineers working on semiconductors or subassemblies a highly portable spectrum analyzer to use at their desks instead of in the lab or to take with them to check manufacturing line issues.” For designers working on complete products, he said, the RSA306 can provide a quick check to verify the product is working properly and has a good chance of passing final EMI compliance.” Tektronix, he said, targets “… the needs of Internet of Things testing across the food chain,” adding that the company offers higher performance real-time spectrum analyzers for semiconductor designers and manufacturers.

In addition to general-purpose signal generators and analyzers, Rohde & Schwarz offers the R&S CMW wideband radio communication tester, which, Emarievbe said, provides universal, efficient tests for all modern mobile radio standards, serving development, validation, high-volume production, and service/repair. The R&S CMW500 version, he said, is the universal test platform for RF integration and protocol development while the R&S CMW290 functional radio communication tester is the cost-effective compact version of the CMW500. And in addition, he said, the R&S CMW270 wireless connectivity tester “… is a cost-effective alternative for development, production, and service focused on noncellular wireless standards. It offers features comparable to those of the R&S CMW500 supporting Bluetooth, WLAN, and broadcast technologies.”

Vitali Penso, an applications engineer at Wireless Telecom Group, said his company provides RF peak power meters and RF/analog AWGN noise generators that can test semiconductor devices, subassemblies/PCBs, and complete products. The instruments can be used at all stages, he said, including R&D, characterization, and manufacturing test. “Our USB RF Peak Power Sensors offer benchtop performance so are suitable for R&D,” he said. “They are small, low cost, and remotely programmable for manufacturing and field applications.” He noted that a function trademarked “Real Time Power Processing” (patent pending) performs 100,000 triggered pulse measurements per second, which he called the fastest in the industry.

Penso added that the company’s “… AWGN noise generators are used in R&D and characterization mainly but can be used in manufacturing test as well.” These Noisecom-branded products, he said, provide noise-generation solutions from the component (diode) level, extending to full automated instruments for BER vs. Eb/No (energy per bit/noise spectral density) testing.

LitePoint also makes test systems for both lab use and manufacturing test. Chris Ziomek, general manager of LitePoint’s Design Test Division, cites as an example the LitePoint zSeries RFIC chipset test system for the lab, which can test LTE devices as well as ones meeting connectivity standards such as the various versions of Wi-Fi.

Ziomek noted that while relatively few companies focus on making cellphone devices, many will be building connected IoT devices, and their designers may be implementing wireless connectivity for the first time. Many will buy a pretested RF module that may have been tested on LitePoint equipment, but others may want to do more—perform their own tests to make sure the RF capability continues to work when integrated into a toaster, for example. To serve all users, he said, “LitePoint has the technology and knowhow to continue into the IoT space.”

Low-power requirements

Low-power performance is a critical aspect of connected-device operation. Hall at NI explained, “DC power consumption has become an increasingly critical issue for modern mobile devices. As a result, RFIC characterization now involves characterization of both RF and DC characteristics. NI addresses these measurement challenges through a broad array of programmable power supplies and source measurement units (SMUs). With these instruments, engineers use both DC and RF measurements to measure device efficiency in a wide range of operating modes.”

Robert Green, senior market development manager for the Keithley product line at Tektronix, cited several specific products his company offers that can help engineers design low-power products and determine power consumption in each operating state. Those products include the new touchscreen 2450 SMU, which can measure low currents to below pA levels; the Series 2280S power supplies, which provide 0.02% voltage setting accuracy; the Model 2281S-20-6 precision DC power supply and battery simulator, which can dynamically simulate a battery’s output during the charge and discharge cycle; and the DMM7510 graphical sampling digital multimeter.

The multimeter and battery simulator, he said, together “… enable the complete characterization of a device’s power-consumption profile in all of an IoT device’s operating states from the sleep modes, to standby modes, to the active and transmit modes. The DMM7510 has an 18-bit, 1-MS/s digitizer and a 27-M measurement memory to capture complex load current waveforms such as the pulse-like load current waveform generated when the IoT device transitions into its transmit mode.”

Keysight, too, addresses IoT device power measurements. “The N6781A SMU with the N6705B DC power analyzer enables designers to accurately measure ‘sleep’ currents of tens of microamps and range up to wireless transmit currents of a couple of amps in a single measurement pass,” Zemede said. “A patented technology in the SMU provides an unprecedented ~28 bits of dynamic range, giving designers new insight into their dynamic energy requirements to maximize battery life of their IoT device.”

In addition, she said, the VXT can be used with a Keysight N6781A SMU to provide the necessary current/power-drain measurements to correlate tests with operating modes. She added that including a Keysight digital stimulus/response PXI module in the chassis with the VXT allows you to send digital RFFE commands and make timing measurements relative to those commands. “The stimulus/response module is optimized for on-the-fly command changes to test the limits of a device,” she said.

Other companies offer power measurement solutions for IoT applications as well. Torgerson at Anritsu said the MD8430A signaling tester was part of a demonstration at CTIA Super Mobility 2015 that showed the ultra-low power consumption enabled by the LTE Cat. 0 power-saving mode. “This world-first demonstration indicated LTE Cat. 0 technology is ready for deployment into IoT devices,” he said.

And Emarievbe at Rohde & Schwarz said the R&S CMW test platform can perform, document, and evaluate many types of complex user-experience tests under simulated, yet realistic conditions. One test scenario, he said, could involve correlation between current drain and signaling or IP activities. “Specific signaling trigger events as well as IP activity trigger events from the R&S CMW500 built-in IP analysis are displayed in a current drain diagram,” he explained.

Conclusion

Connected and IoT devices present unique combinations of measurement challenges that the companies mentioned in this article are prepared to address. For example, Zemede at Keysight said the company is well positioned to offer customers a variety of products and form factors, all running a common core set of measurement applications. “Whether you want a standard box instrument with built-in keyboard and display, a full PXI custom chassis that you can fill with the modules you want, or a one-box tester focused exactly on your problem, we offer all of those form factors running a common set of X-Series applications,” she said.

Hall at NI said, “One of the key characteristics of NI’s solutions for wireless and semiconductor test is the incredible integration between the tools for all facets of the product life cycle and value chain. This deep level of integration … allows our customers to bring products to market much faster.”

Zemede concluded, “As the number of deployed IoT devices expands into the billions, the capability to ensure absolutely reliable connectivity will become essential. Creating seamless connectivity across the entire ecosystem—devices, infrastructure, cloud, remote applications, post-processing, services—starts with the capability to create better designs, utilize increasingly realistic simulations, and perform meaningful and cost-effective testing.”