Communication Electronics

The huge communications applications area continues to have a plethora of innovative new products. We have found interesting evolving wireless specifications, low-cost wireless methods, high-speed backplane connectors, GbE server solutions, automotive communications, 10 G PHY performance, and test systems to verify it all.

ZigBee specification updateThe ZigBee Alliance (www.zigbee.org) has announced new features for the network architecture’s specification, giving more choices to manufacturers. The ZigBee Feature Set was published in 2006. An expanded set of features known as ZigBee Pro has features for larger networks, offering more management, flexibility, and performance choices.

It includes support for fragmentation (the ability to divide longer messages and enabling of interaction with other protocols and systems), frequency agility that allows networks dynamically change channels should interference occur, automated device address management for large networks with added network group addressing, and enhanced secure wireless commissioning capabilities. ZigBee uses self-organizing and self-healing mesh networking to enable robust communications over the globally available 2.4-GHz frequency, with 868/915-MHz technology available in select countries.

ZigBee and MiWi protocols IEEE 802.15.4 is often used in reference to the ZigBee standard, but the standard just uses IEEE 802.15.4 as the physical medium for wireless networking. 802.15.4 specifies three frequency bands designated for use in industrial, scientific, and medical applications: 868 MHz, 915 MHz, and 2.4 GHz. There are several protocols that use the specification—among them ZigBee protocol is probably the best known, but it is still in its infancy in terms of widespread deployment. Other protocols do exist, such as the MiWi protocol from Microchip Technology (search.microchip.com).

The ZigBee protocol mandates interoperability, which is one of its best features. The typical ZigBee protocol stacks for network coordinators range in size from 64 to 96 Kbytes and require a substantial amount of RAM and nonvolatile memory to store routing information. Applications that don’t require the interoperability or large network size offered by the ZigBee protocol can use the MiWi protocol, which provides the capability of supporting over 1,000 nodes and point-to-point, star, and limited-mesh topologies. Its protocol stack is only 20 Kbytes for a coordinator and 4 Kbytes for an end device. With costs near the sub-$2 dollar range for the transceiver and options for small software stacks that enable the use of very-low-cost microcontrollers, adding IEEE 802.15.4 wireless capabilities to products can be done for a price appropriate to some cost-sensitive embedded applications.

High-speed connectorsDistributor Newark (www.newark.com) is now stocking the I-Trac backplane connector system from Molex. The I-Trac is said to feature superior impedance control, lower cross-talk and higher overall bandwidth. It enables high-speed data rates scalable from 2 to beyond 12.5 Gbits/s, supporting the next-generation server, storage, telecommunications and data networking applications. It also features the same part numbers for both standard and orthogonal architectures by allowing the rotation of the headers 90 on one side of the midplane. Network control boardWIN Enterprises (www.win-ent.com) has announced the MB-09015, a network control board with dual Intel Xeon processors and ten GbE LAN Ports. The dual-socketed board is designed for network security and other demanding enterprise network applications, including anti-spam, antivirus, load balancing, firewall and Unified Threat Management. It has a E7520 chipset that supports FSB 800 MHz and Extended Memory 64-bit Technology. Up to 16 gigabytes of DDR2 system memory can be supported. PCI-Express technology provides a total system bandwidth of up to 32 Gbits/s. Automotive communications allianceSTMicroelectronics (www.st.com) and Automotive Communications Systems recently announced plans to jointly develop communications ICs for Vehicle and Infrastructure Integration (VII). The VII initiative is investigating the potential safety benefits of car-to-car and car-to-roadside high-speed communications. If successful, the automotive OEMs would roll out on-board equipment on all new vehicles sold in North America and the Federal Government will install infrastructure on major roadways. ACS, headquartered in Ann Arbor, MI, has a patent pending on a vehicle-to-vehicle and vehicle-to-infrastructure communications architecture which address three of the major challenges facing the VII initiative: statistically determinant channel access necessary for safety systems, robust communications in a multipath environment, and precision vehicle location within 1-ft resolution. 10GBASE-T PHY testingSolarflare Communications (www.solarflare.com) has successfully completed conformance/interoperability tests of their 10GBASE-T PHY on a worst-case, 105-m link in the University of New Hampshire Interoperability Lab. The test demonstrated that one implementation can work not only on a typical cabling link or channel, but also on the worst-case channel specified by the 10GBASE-T unshielded twisted-pair cabling standard.

While the IEEE 802.3an standard sets 100 meters as an objective for operation on unshielded twisted-pair cabling, conformance to the standard is only achieved by meeting all of the protocol implementation conformance statements (PICS), including operation on worst-case channels specified in terms of cabling link or channel impairments. The demonstration PHYs successfully interoperated on a 100-m, four-connector channel with 4.0 dB of insertion loss margin.

Communication test systemsSaid to be the first one-platform protocol emulation and conformance test solution for Ethernet Operations, Administration and Maintenance (E-OAM, as defined in IEEE 802.1ag and ITU-T Y.1731), N2X N5581A and N5585A multiservices test solutions from Agilent Technologies (www.agilent.com) test a Carrier Ethernet device’s protocol implementation against many thousands of similar emulated devices, enabling CFM scalability characterization without a test-bed of thousands of real devices. The complementary N2X N5718A CFM conformance test suite validates device compliance to IEEE 802.1ag, draft 8.

The MG37020A microwave signal generator from Anritsu (www.anritsu.com) integrates RF hardware, enhanced computing, and digital interfaces to achieve frequency switching speed of 100 µs per point an order of magnitude faster than comparable YIG-based signal generators – while maintaining low phase noise of typically 101 dBc/Hz at 10-kHz offset from 10 GHz.

The AzCert Wi-Fi 802.11n Certification Test Suite from Azimuth Systems (www.azimuthsystems.com) fully automates the complex and time-consuming Wi-Fi Alliance 802.11n draft 2.0 certification test plan. All tests are controlled and configured by the company’s Director II test executive, which allows the entire series of over 100 test cases to be run together or incrementally.

An all-in-one solution for vehicle distance radar or aerospace and defense applications, the ZVA-Z110 mm-wave converters from Rohde & Schwarz (www.rohde-schwarz.com) add the 75 to 110-GHz (W band) frequency range to the company’s high-end network analyzers. Four-port network analyzers do not require an additional external generator, which reduces measurement times. ■