By Ann Steffora Mutschler
Electromagnetic interference (EMI) cuts across all application segments, whether it’s aerospace and defense and its various tangents, or in a handset, virtually touching a large majority of engineering teams today.

The reason this issue affects so many engineering groups is because as modulation schemes become ever more complex they become even more sensitive to signal-to-noise ratios. Signals that are significantly lower and weaker to receive are much more susceptible to interference either intentional or unintentional.

“If you look at CDMA technology which really uses old military spread-spectrum technology, essentially you’re trying to pick a very weak signal out from the noise floor using a very elaborate algorithm to do that,” said Erick Olsen, director of marketing for mil/aero at NXP. “On the RF side that signal is still very, very small and so even if you know exactly where to look for it if there is unintentional jamming, which comes in the form of a handset that has wireless LAN. There are other signals roaming around (Zigbee, Bluetooth, etc.), and those signals can unintentionally interfere with that very, very low signal level.”

In the military, that jamming can be intentional. In the consumer world, that jamming is unintentional and sometimes even self-induced.

The aerospace industry, meanwhile, is constantly striving for more efficient “green” aircraft that can travel further using less fuel. “One way to achieve this is by reducing the weight of the aircraft,” said David Johns, vice president of engineering at Computer Simulation Technology. “AG Composite materials are increasingly used instead of aluminum sheet. Such materials typically do not provide the same levels of electromagnetic shielding because their effective electrical conductivity is lower, making the aircraft more susceptible to interference.”

A modern aircraft contains literally miles of cabling, and this can contribute significantly to the overall weight. That weight can be reduced by removing layers of shielding in the cable, or implementing shielding over reduced sections of the cable, but there is inevitably a tradeoff between weight and EMC/EMI shielding performance. The electromagnetic “threats” to aircraft systems include severe currents and fields associated with lightning strikes, electromagnetic pulses (EMP), high-intensity radiated fields (HIRF) from external transmitters and EM noise generated by internal systems such as wireless devices, he said.

In defense applications, there is a requirement for very good control of the spurious, Olsen noted, referring to any signal that is not the intended signal.
“If I’m operating on a UHF communications link between the ground and the air on an aircraft or a long-range radar for tracking inbound attacks, by design I’m only allowed to transmit one specific frequency or within a band of frequencies, and that is very tightly controlled,” he said. “Any energy that is outside of that band is considered spurious or unwanted radiation, so if you put a lot of energy into that unwanted frequency before it actually transmits you are actually wasting a lot of energy. By creating unwanted energy you then have to find a way to filter that out so you are expending energy in the first place in an unwanted RF spectrum, and then you have to add cost to the system to filter it out. So it has an effect on efficiency. If it’s a big ship-borne radar maybe it’s not a big deal, but if you are in an aircraft-borne or in a remote-sensing-type application, every little bit of current or power consumption is a big deal. Then of course adding additional filtering adds weight and complexity so therefore adds cost which is not wanted either,” he continued.

Another impact of EMI is received desensitization. If the RF transmitter is putting out a bunch of unwanted energy, even if it can be filtered out before it gets to the antenna that unwanted energy might be still around on the transmitter. “If your transmitter and receiver are well isolated or protected from this extra energy, that energy bleeds into the RF on the receive side and essentially decreases the signal-to-noise ratio. It makes it harder to pick out that very low signal level from the noise floor as the noise floor now comes up. So you get desensitized, making it harder to make that communication link on a radio or on radar, which makes it harder to pick up a target at a longer distance,” Olsen explained.

Advanced algorithms are used on a lot of multiple tracking radars these days with the advanced phased arrays and Active Electronically Scanned Array radars to detect both the target as well as its characteristics, such as its speed, size and whether it’s a plane or a missile. If the signal is too weak to be fully detected that can pose a significant problem.

One brute force way to deal with this kind of EMI is to shield parts of the system with metal enclosures, adding ferrite beads and other filters to the system. Another option is to transmit at higher power levels. If it is a radar application, an aircraft-borne radar or a land- or sea-based radar, detecting a that is farther away may mean hitting it with more energy so that if there is any jamming the signal is strong enough to overcome that.

Another technique used often in both military and commercial applications, as well as cell phones, is called frequency hopping. As the phone transmits voice or data coming it constantly changes the frequency. This uses very precise timing and a lot of it is GPS-based, so having an accurate GPS timing signal coming from the satellite is a big deal.

EMI in the car
With the ever-increasing amount of electronic content in automobiles today, EMI is a significant concern. Aveek Sarkar, vice president of product engineering and support at Apache Design, observed that too much EMI can cause coupling between subsystem PCBs within the vehicle. “Let’s say you have a printed circuit board, which has the chips that control the airbag, and then there is another printed circuit board that controls the GPS. Let’s say the GPS one is transmitting too much EMI and that couples onto the wires on the board that controls the airbag. That leads to noise and it can prevent the airbag board from operating properly. For that you have to ensure that the compatibility of the devices in the presence of EMI is sufficiently high.”

The question is how to prevent it. There are certain things that can be done in the design to suppress the noise, but there is only so much de-capacitance that can be put on a package or board to suppress the noise coming out of the chip. “You need to design the chip in a proper manner so that the current is not as leaky, there is enough decap and the noise is not generated,” Sarkar said.

For aerospace applications, engineers are dealing with these issues by designing EMC/EMI protection into the airframe and avionics systems, noted CST’s Johns. “At the airframe level, conducting strips may be applied to composite panels in order to provide a deliberate path for RF current flow, diverting high currents and field strengths away from critical or sensitive equipment. Electromagnetic field simulation is used earlier in design, and more extensively, to determine optimal locations for EMC/EMI protection. Engineers may simulate the EMC performance of the airframe for different structural designs. Broadband shielding effectiveness can be calculated and important effects captured, such as electromagnetic resonances generated by EM waves bouncing across airframe structures or inside compartments/cavities. Ultimately the goal of simulation is to reduce the number of physical tests required to certify or qualify the aircraft for EMC, which is both a time-consuming and costly process.”

Further, simulation can be used to model various “threats” such as lightning strikes and visualize the resulting current distribution induced in the airframe, and can also be used to predict voltages and currents coupled into internal cabling, enabling the impact of removing layers of shielding to be assessed. At the avionics level, filtering may be applied to suppress interference over certain frequency bands and non-linear transient protection devices employed to clamp voltages/currents to acceptable levels. A tradeoff between filtering/transient protection and shielding could be an important design scenario to consider, he pointed out.

“Electromagnetic analysis may be applied in the design of avionics enclosures, printed circuit boards and components, ensuring that they are less susceptible to electromagnetic interference. Simulation models can be parameterized, so that trends in performance for different design options can be easily extracted. Electromagnetic simulation codes can be run on high performance computing systems to speed up the analysis and solve highly complex models. A large model can be decomposed into many smaller pieces and distributed over a computing cluster. The different pieces are solved in parallel and recombined at their boundaries to yield the overall system response,” Johns added.

The bottom line
As with all power-related issues, setting goals at the very beginning about what the intended signal should look like and how to reduce the unintentional energy is critical.
“Understanding the spectral requirements is a starting point for a good, solid design,” NXP’s Olsen concluded.

By Pallab Chatterjee

Security technology and low power typically don’t go together in the same sentence, let alone the same device. All of that is starting to change, though.

With 2% of the world’s energy being consumed by data centers, the new Energy Star guidelines and their associated tax incentives have been driving IT updates and upgrades since 2009 . The security industry is not implementing the guideline in the same manner—their products cannot move to hibernate or sleep states to save power and must be constantly in active mode to provide data protection—but power consumption is becoming much more important.

The traditional IT environment has implemented the TCP/IP stack as a L2-L3 appliance, L4 appliances, L5-L7 appliances or a L4-L7 appliance. Most systems have a number of dedicated hardware appliances performing load balancing, firewalls, Intrusion Protection Systems (IPS), in addition to the server hardware (L5-L7).

The low-power IT solution has been targeted at a conversion to Energy Star Rated multicore mobile processors with DDR3 to reduce the net energy use per U1 appliance or blade at the same throughput. As network bandwidths scale up from 100Mb/s to 1G/ 10G/ 40G/ 100G+, the security appliances have to scale also.  The higher bandwidths produce a new security issue of needing inward-facing security to the server environment to offset theft of data from within, in addition to the traditional outward facing defenses against hackers, malware and viruses.

The security appliances have targeted power conservation in two directions. One approach is to combine functions into a single appliance. The second is to add new high-performance hardware onto already an existing Energy Star chassis.  CrossBeam, for example, has a single appliance that combines 2 outward-facing load balancers (LB), 8 firewalls, 2 IPS, and 2 inward-facing Lbs. This appliance operates with a single line cord function and replaces the 14 other line cord appliances.  It is a single open Linux/Unix core processor that can be easily configured for most applications while providing 10G throughput. The company plans to release a 40G product in the next several weeks, soon to be followed by an 100G+ product.  The 40G unit promises more than 90% power reduction vs. the 14 40G appliance installation. This product is currently FIPS 140/2 compliant.

Netronome has resuscitated the Intel ISX network processor family and ported it to the TSMC 65nm process node. The resulting network flow processor operates in the LB and Firewall functions and provides a 40G-100G solution through either a PCI gen 2 or QPI interface to a standard IA environment. The revised silicon sports 40 cores with 8 threads each for a total of 320 active cores, with on-board thermal management, in a unified L2-L7 appliance. As the product is available etiher as a plug in board or as a socketed network “co-processor,” the Energy Star compliance gets pushed off to the IA-based main processor board with DDR3 memory.  Like the Crossbeam product, it supports open source applications and has built in hardware crypto.

Black Ridge Products has a similar single-function appliance, a First Packet Authentication device that hides the IP address of clients of the appliance from being detected.  The product uses new low-power custom silicon that is integrated into a standard low power U1 1A system Unix system that is Energy Star-approved.

Not to be left out, NXP has a new series of passive tags that are both EEPROM and mask programmable with code information. These have been moved to a 140nm process that can now operate from 1.8-5V in both contact and contact-less mode.

The trend in power is centered around migration to low power, small geometry processes for the custom security hardware, and supplementing those devices into existing Energy Star appliances or merging multiple devices into single units at higher throughput.

By Ed Sperling

Business seems to be picking up everywhere in the design world, with an emphasis on speed—quicker deals, faster product rollouts and overall time to market—and all of it with an underlying emphasis on low power and tighter power budgets. Could it be that after the recession, everyone is trying to get back on track quickly?

Virage Logic completed the acquisition of NXP’s IP technology and its development team. That comes on the heels of its recent acquisition of ARC. The fact that Virage completed both of these acquisitions in a 12-day period is nothing short of an accounting miracle. And just in case the company didn’t have enough to do, it added a Silicon Browser for post-silicon bring-up and system debug.

Android seems to be getting its share of attention these days. Mentor Graphics introduced an Android Development System for Texas Instrument’s OMAP35x processors. TI’s processors also include ARM Cortex-A8 technology, which puts ARM squarely in the center of this effort, as well, with a heavy push toward better battery life. But will any of this take a bite out of the Apple iPhone?

On the get-things-done-quicker side, Digital Imaging Systems used Synopsys’ Galaxy Custom Designer to achieve first-pass silicon in 22 days. Not all of it was from scratch, of course, but that’s still a very tight timetable.

And Atrenta’s deal with Fujitsu’s Kyushu Network Technologies is aimed at reducing design risks in integration of third-party IP from multiple vendors with different clock domains. Translation: Faster time to market.

Also on the business side, Cadence expanded its design alliance with Toshiba for the consumer and mobile markets.

Intel invested millions of Euros in an Exascale Computing Research in France, as part of Intel Labs Europe. This is the second time in two weeks that Intel has paid out big bucks to appease antitrust regulators. This deal will add 900 new research jobs in Europe. That follows Intel’s settlement with AMD, clearing the way for Intel to go after ARM with its Atom chip.

ARM’s comeback was largely a reiteration of the strength of its ecosystem. It struck up a strategic architectural license agreement with Infineon for advanced security applications and created a solutions center for Android.

By Ed Sperling

The big news of the week is that Intel bared its teeth and declared war on almost everyone in the processing market—from supercomputers to cell phones. Whether Intel is successful in these markets remains to be seen, but its lineup now includes Atom processors, the regular computer processor line, and SoCs that can run x86 code. The big question for many potential competitors is just how low Intel can get its power consumption—and how quickly.

Apparently it’s the season to cut deals with foundries. Mentor Graphics’ low-power technology was included in TSMC’s reference flow 10.0. The deal encompasses everything from the Olympus SoC implementation system to the 0-In CDC tool for verification. So much for the point-tool providers.

SMIC, the Shanghai-based foundry, will be using Virage Logic’s AEON multi-time programmable non-volatile memory for RFID applications. Given the growth in short-range communications, both real and projected, this could prove to be very significant.

Synopsys took the covers off its StarRC Parasitic Extraction Solution for analog/mixed-signal and custom digital design. The rollout is a combination of its Star-RCXT extraction technology with Raphael NXT 3D fast field solver. What’s interesting here is that integration of technologies is becoming far more important for two reasons. First, it makes it much easier for customers to use tools that are integrated. And second, it makes it much harder for smaller players to gain a foothold in the market. Expect to see more of these kinds of announcement.

Actel introduced a catalog of firmware that’s compatible with the IP cores in its embedded processor. This isn’t exactly like the old Sears Roebuck catalog, though. It’s actually an executable program that allows you to configure firmware drivers, hardware abstraction layers and design examples. Welcome to the electronic world.

ARM and NXP launched a rapid prototyping tool set for microcontrollers. ARM also extended its serial-wire debug technology to include multi-chip and multicore debugging with only two pins. This is an update of a mature technology that most of the ARM world already uses, but it’s good to see they’re still working on it.

TSMC is going green, and so are its suppliers—whether they want to or not. The foundry announced a supply chain carbon inventory assistance plan to disclose greenhouse gas emissions. Given the pollution levels across the Taiwan Strait, this certainly can’t hurt.1

TSMC also is looking a little blue—as in Big Blue. The foundry will be churning out Power chips from AppliedMicro based upon the architecture created by IBM (and Apple and Motorola/Freescale).

MIPS inked a deal with Opulan Technologies in Shanghai to provide its 24KEc core to the fixed-network supplier. These kinds of deals are an indication of a full-fledged economic recovery in that part of the world.

Cadence, meanwhile, cut a deal with Linear Technologies for a slew of mixed signal tools. It’s interesting that the analog chipmakers all complain about the tools that are available, but they still buy them. What are we missing?