Piecing together EMC compliance

According to Diesso, “AR products are designed with a long history in EMC. Each product line is developed to differentiate AR from the rest of the market.” He cited several examples: the 700-MHz to 6-GHz bandwidths of the company’s wideband amplifiers, the capability of the FA7000 field analyzer (Figure 1) to characterize signals, and the speed of the FFT-based DER2018 EMI receiver. “We continue to provide the highest power RF and microwave solid-state amplifiers in the marketplace and offer accessories which decrease test time as well as increase measurement accuracy,” he added.

New EMI receiver

Mark Terrien, EMC business manager at Keysight Technologies, said his company focuses on both compliance and precompliance EMI measurement solutions to address emissions testing at every stage of the product development cycle. For compliance testing, the company offers the new N9038A MXE EMI receiver (Figure 2), which conducts measurements in accordance with CISPR 16-1-1 and MIL-STD-461F specifications. “For a complete EMI test solution,” he added, “Keysight Solutions Partners provide a single point of contact to combine the MXE with chambers, antennas, software, value-added integration, probes, and more.” In addition, he said, “The Keysight N/W6141A EMI measurement application on the X-Series signal analyzers performs precompliance measurements and diagnostic evaluation of product designs.”

Terrien cited differences between compliance and precompliance testing. “In EMC compliance testing,” he said, “success depends on moving products through the test queue quickly and efficiently. Keysight offers the standards-compliant N9038A MXE EMI receiver to fully test devices up to 44 GHz with outstanding accuracy of ±0.5 dB at 1 GHz, enabled by an all-digital IF.”

As for precompliance test, he said, “To avoid costly delays that can result from failed compliance testing, product-development engineers can find and fix problems before they enter the test chamber with the N6141A EMI measurement application on the N9030A PXA, N9020A MXA, or N9010A EXA X-Series signal analyzers,” or they can use the W6141A measurement application on the N9000A CXA for a low-cost precompliance test solution.

Keysight products also address debugging and troubleshooting. “The Keysight MXE EMI receiver is a diagnostic signal analyzer, so test engineers can identify the cause of noncompliant emissions and provide clients with advice on how to improve test results,” Terrien said. “The Keysight EMI measurement application can troubleshoot devices that did not pass emissions testing.”

Terrien cited some specific features of the company’s products. “To streamline EMC measurements,” he said, “the Keysight MXE EMI receiver offers capabilities designed for easier identification and evaluation of noncompliant emissions. It has complete sets of commercial and military resolution bandwidths and diagnostic detectors including peak, quasi-peak, EMI average, and rms average, and the built-in library contains commercial and military limit lines.” In addition, he said, engineers can customize their own solutions with the easy-to-use editor.

He said the MXE also features a time-domain scan to reduce overall measurement time, a built-in disturbance analyzer to automate click measurements, a strip-chart function to track and evaluate signal trends vs. time for up to two hours, and an amplitude probability distribution function to prepare for future requirements. In addition, the MXE can monitor the spectrum to make it easier to identify the frequency of peak emissions prior to final measurement.

“In addition to being a fully compliant EMI receiver,” Terrien said, “the MXE also is a diagnostic signal analyzer, so test engineers can identify the cause of noncompliant emissions. Built on an upgradeable platform, the MXE offers an upgradeable CPU, memory, disk drives, and I/O ports as well as the opportunity to add functionality and measurement applications with simple license key upgrades allowing EMC test facilities to keep test assets current and increase instrument longevity.”

Precompliance, debug, and troubleshooting

Rigol Technologies also addresses EMC test. “We realize that almost every design has EMC challenges,” said applications engineer Jason Chonko. “Our goal is to help customers overcome those challenges as quickly and painlessly as possible.” Rigol’s products are primarily used throughout precompliance, debug, and troubleshooting, he added.

According to Chonko, “Our main EMC offering is centered around our spectrum analyzers. The DSA800 family is our most recent platform. Models in this family are available in 1.5-GHz, 3.2-GHz, and 7.5-GHz max frequency, and all can accommodate tracking generators and EMC-focused software upgrades.” He added, “Our spectrum analyzers feature an easy-to-use software tool, the EMI Test System, that allows users to set up scans, set limit lines, and ease precompliance data collection.” The analyzers (Figure 3) also feature an optional EMI firmware upgrade (DSA800-EMI) that enables FCC bandwidth selection, EMI filtering, and a quasi-peak detector.

In addition, Chonko said, the company offers RF signal sources like the DSG3000 series, arbitrary waveform generators like the DG1000Z and DG5000 series, and oscilloscopes that range from 50 MHz to 1 GHz.

Tektronix also provides instruments for EMC test. According to Matt Maxwell, product manager for spectrum analyzers, the RSA306 spectrum analyzer with SignalVu-PC, the RSA5100B spectrum analyzer, and the MDO4000B mixed-domain oscilloscope can all be used in EMI diagnostics applications. MDO4000B Series product manager Lisa Beiker added, “The MDO4000 series combines the functionality of a spectrum analyzer with a mixed-signal oscilloscope. This integration enables the unique capability to time-correlate spectrum analysis with analog and digital signals, so problems can be isolated more precisely and faster than with conventional tools.”

Maxwell said the spectrum analyzers can serve in precompliance test, debugging, and troubleshooting while Beiker said the MDO4000B can minimize the time it takes to find sources of interference when debugging and troubleshooting EMI issues. Both agree on this point: “We find customers across many segments with similar problems in consumer wireless, medical, aerospace, and automotive applications.”

Maxwell noted that the real-time capabilities of the RSA306 and the RSA5100B have been useful for EMI diagnostics and troubleshooting, allowing engineers to find signals that other analyzers and most traditional EMI receivers miss. “This feature on the RSA306 is particularly interesting because it allows for quick troubleshooting,” he said. “Because of very fast processing, the spectrum display updates very quickly.” He said the real-time spectrum is shown as a color bitmap representing hundreds or thousands of FFTs, resulting in a display that includes infrequently occurring events. “These are the very kind of events that can cause headaches when a design is sent to an EMI compliance lab—tracking down and fixing issues that can cause testing failures can be very time-consuming and expensive. Real-time technology can help uncover these signals.”

He cited several features of Tektronix spectrum analyzers, including continuously variable RBW and span settings as well as real-time triggers on signal density. “Also,” he said, “only Tektronix offers displays like DPX Zero Span, which gives up to a 50,000 waveforms-per-second update on a traditional Zero Span display for more insights.” He added that the way the RSA5100B and SignalVu are set up makes it easy to connect different domains and observe signal behavior over time. “This last feature can be very helpful as it could, for example, let you correlate time, frequency, and other domains with markers that automatically link across multiple displays,” he added.

Finally, he said, both the RSA306 and RSA5100B support CISPR +Peak detection, and both can use the MIL-STD filters, which can be useful in precompliance, diagnostics, and troubleshooting. In addition, the RSA5100B supports a CIPSR quasi-peak detector, which can be helpful in EMI precompliance.

Beiker elaborated on the MDO4000, whose time-correlation function facilitates fast and precise EMI troubleshooting. “In troubleshooting EMI, the engineer needs to physically locate the problem (such as transient emission) and then electrically identify the source of the problem so it can be fixed,” she said. “The MDO4000 combines an oscilloscope, spectrum analyzer, logic analyzer, and protocol analyzer in one box. A single trigger controls all of the inputs on the MDO4000—the four analog channel oscilloscope inputs, the 16 logic channel inputs, and the spectrum analyzer input. A single acquisition can contain a seamless time capture of the signal activity on all of these inputs.”

As a result, engineers can observe activity of all the signals simultaneously on one time-correlated display (Figure 4). “With the spectrum analyzer, the user can zero in on the EMI problem,” Beiker said. “Using the universal trigger and capture of all inputs, the user can study the time-domain characteristics of the RF signal as well as surrounding signals on the circuit board to quickly and more precisely isolate problems. The MDO4000 has the versatility and power to provide a complete system view of coincident events in your device.”

Generators and amplifiers

Other companies with recent product introductions, as covered in our January issue, include ETS-Lindgren and Instruments for Industry (IFI). The latter, a unit of AMETEK Compliance Test Solutions through AMETEK’s acquisition of IFI parent company Teseq, recently debuted a dual-mode, solid-state amplifier that combines continuous and pulse operating modes. The new S31-500-900P amplifier has been optimized for performing 600-V/m radar pulse radiated immunity testing in the 0.8-GHz to 3.1-GHz band.¹ The amplifier has a 500-W continuous rating along with the capability to deliver more than 900 W in the pulse mode.

Suitable for labs and many automotive OEMs, the S31-500-900P supports tests in accordance with specifications set by Ford and General Motors and followed by other manufacturers. The unit offers a peak power rating that allows it to generate a 600-V/m test with either high-gain, narrowband antennas or a single wideband antenna. When used with narrowband antennas, the S31-500-900P has sufficient power to allow overtesting or provide greater coverage of the EUT to reduce testing time.

For its part, ETS-Lindgren unveiled its EMField Generator, which the company describes as integrating separate components into a compact, modular, and efficient testing tool. The company noted that for decades radiated immunity testing has been performed using bulky RF power amplifiers, and immunity systems have been inherently inefficient, losing up to half of their power to heat, cable loss, couplers, and other hardware components. Until now, engineers have had to compensate for these losses by increasing the size of the amplifiers.

“We have challenged the traditional assumption that delivering a higher field strength requires more power, and we are bringing a game-changing technology to the market,” said Bryan Sayler, senior vice president of ETS-Lindgren. “For labs looking to test in the 1-GHz to 6-GHz range, the EMField Generator provides a highly efficient and portable alternative to the traditional amplifier and antenna configuration.”

The EMField Generator combines amplifiers, directional couplers, power meters, and an antenna array into one simplified design.

In related news, Rohde & Schwarz announced that it has expanded its R&S OSP modular platform for wiring RF test equipment and DUTs (Figure 5). The company said the modular R&S OSP gives test engineers in production facilities, test labs, and R&D departments a range of options for quickly setting up RF wiring configurations and controlling them manually or via a computer. A new I/O module makes it possible to control external equipment via differential lines. It offers 16 differential RS-422 outputs and four analog output voltages for controlling antenna systems, for instance.

Two new transfer relay modules (DPDT) each have two SMA or N relays, making it easier to implement cross-wiring between two RF paths. Also new is a nonterminated octuple changeover relay (SP8T). In addition, Rohde & Schwarz has complemented the universal SPDT and SP6T monostable relay modules with bistable versions. And power sensors in the R&S NRP-Z family now can be integrated into the R&S OSP, enabling users to set up compact configurations for power measurements. The company said that its application-specific modules make the open switch and control platform suitable for setting up EMC and over-the-air test systems.

Planning for the EMC Symposium

At the upcoming EMC Symposium, AR is likely to highlight its line of amplifiers. “One main area of emphasis is the highest power RF and microwave solid-state amplifiers on the market,” Diesso said. In addition, the company’s MultiStar products, including the MT06000 MultiTone tester,  the FA7000 field analyzer, the DER2018 FFT-based EMI receiver, and the 200-W solid-state class A 700-MHz to 6-GHz amplifier as well as improvements in emcware will be demonstrated.

Terrien at Keysight said, “We’ll have all of our compliance and precompliance products at the symposium, and we will be highlighting our new 3.6-GHz MXE EMI receiver model and real-time diagnostic capability available on our precompliance instruments.” And Chonko at Rigol said, “We will be featuring the DSA875-TG 7.5-GHz spectrum analyzer and the DSG3060 RF signal source.”

Reference

1. Nelson, R., “Vendors target conducted, radiated immunity,” EE-Evaluation Engineering, January 2015, p. 27.