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25 Jul

Supply Chain Management Maximizes Sweet Efficiencies

Posted in Uncategorized on 25.07.13

By now, the supply-chain metaphor is a familiar one. It helps us visualize the coordinated flow of goods and information, from raw materials through to the end user.

scmThe supply-chain metaphor also signifies interdependence. If any single link is missing or weak, the supply-chain effort becomes ineffective or may even fail. From a conceptual viewpoint, therefore, it’s hard to say that any one function or link is more important than another. In practice, however, certain functions have an exceptionally strong impact on the success of a company’s supply-chain program.

One of those areas is purchasing. Purchasing professionals are on the “front lines” of supply-chain management. Their position at the top of the chain – linking manufacturer and supplier – is crucial to the success of the manufacturer’s relationship with its customers down the line.

“If you look at supply-chain management from a holistic point of view, purchasing is where the rubber hits the road;’ says Greg Cudahy, associate partner in Andersen Consulting’s Supply Chain Strategy Practice. Not only is purchasing one of the supply chain’s crucial links, he explains, but it also plays a role in achieving one of supply-chain management’s main goals: better cost containment.

Purchasing’s contributions in that area are vital, Cudahy says. He cites the example of the commodity-driven food-processing industry, which has very high materials costs. For most food processors, a 1-to 3-percent reduction in the cost of inbound materials greatly outweighs a 10-percent reduction in logistics costs, he reports.

Reducing costs is right up purchasing’s alley, of course. But the traditional approach of simply negotiating the lowest price for raw materials or components doesn’t fit well with the supply-chain philosophy. That’s because supply-chain efforts always look toward the ultimate customer – something few purchasing professionals are rained to do, says Dr. Larry C. Giunipero, professor of purchasing and marketing at Florida State University in Tallahassee. “Typically, they think of themselves as

just acquiring goods and services,” he says. “They feel they’re too far removed from the customer.”

Giunipero and former colleague Dr. Richard Brand last year surveyed 52 members of the National Association of Purchasing Management (NAPM) about their views on supply-chain management. The researchers found that most respondents defined supply-chain management as either “good relationships with suppliers” or “partnership arrangements with select suppliers.” Giunipero and Brand note that, although these phrases accurately describe some of the respondents’ primary responsibilities, they are far from reflecting the real meaning of supply-chain management. A smaller group saw supply-chain management as optimizing the flow of goods and information from suppliers to the final customer – a view that matches the one held by many logistics professionals.

Respondents also revealed their narrow focus on the supplier-buyer relationship when they rated their suppliers as the most important party in the supply chain. On a scale of 1 to 7, with 7 being very important, they rated suppliers as 6.48. Next in line are final customers, with a ranking of 5.87.

Giunipero finds that last figure to be encouraging, since it seems to indicate a growing awareness of the customer as the ultimate focus of supply-chain management. In the future, it will be critical that purchasing professionals become more customer-focused, he says. “At least right now, they see their contributions to their organizations very narrowly. I hope that will change.” Cooperative Venture

The way to achieve that kind of change is by increasing purchasing’s cooperation with other links in the supply chain, both upstream and down. Progressive companies  are discovering several ways they can put that theory into practice.

Perhaps the greatest contribution purchasing can make to a supply-chain management program is in the area of vendor relations. Andersen Consulting, for one, recommends that companies use the purchasing function to strategically manage suppliers in order to reduce the total cost of owning materials and services. By this, the consultants mean that buyers and suppliers should develop cooperative relationships that reduce costs and improve efficiency with the aim of lowering prices and enhancing margins for both parties.

ibmSome companies – including Bose Corp., IBM Corp., Honeywell Inc., and Allied Signal – are making this a reality by actually bringing carefully selected vendors into their plants or warehouses. This approach is known as JIT II[TM], a concept that originally was developed by former Bose Corp. Director of Purchasing and Logistics Lance Dixon. Under JIT II, vendors have access to production schedules. Based on that and other information, they order raw materials, parts, or components and get

them to the Just-In-Time manufacturing line on time. The benefits for the buyer are significantly lower costs and reduced administrative burdens. The vendor gets higher sales volumes, lower cost of sale, reduced administrative costs, and long-term contracts. Both parties, of course, also benefit from the close relationship that is required to make this joint effort work.

Some buyers and suppliers are taking an even more radical step by jointly examining the supplier’s manufacturing processes and the buyer’s internal administrative  processes to identify and root out duplications, inefficiencies, and other problems that add cost. Giunipero cites the example of the auto manufacturers. Several are  working with their first-tier (direct) suppliers and their second-tier suppliers (the suppliers’ suppliers) to redesign not just products but also the vendors’ manufacturing processes. By doing so, they are finding ways to reduce vendors’ production costs on the condition that both buyer and supplier share in the savings.

Clearly, that’s not a job purchasing professionals can do on their own, and that is leading some companies to develop cross-functional procurement teams, Cudahy notes.

“In the last five to seven years, we’re seeing the idea of cross-functional customer-service teams being applied back up the chain… Procurement teams now are

utilizing that same concept.” One company that has created procurement teams is Union Camp Corp. The company disbanded its corporate purchasing department and replaced it with eight “supplier management teams.” These multi-functional groups plan purchasing strategies, develop specifications, select suppliers, and negotiate price and service levels.

In addition to purchasing, procurement teams often include representatives of engineering, research and development, manufacturing, marketing, and customer service. Cudahy suggests that purchasing professionals, with their existing close relationships with vendors, are in a good position to lead such a team – provided they can leave their bias toward cost control behind.

That’s not to say that cost control is not important, but the procurement team has bigger fish to fry. Joint process re-engineering efforts, Giunipero says, offer such potential benefits as cutting order-cycle times, getting new products to market faster, reducing inventory costs, improving product quality, and increasing reliability of product delivery.

The key to achieving such wide-ranging goals is maintaining a focus on the ultimate customer, he emphasizes.”If your company’s biggest customer is focused on product   quality, then you have to get that into your suppliers’ processes,” he asserts. “If your customer wants timely delivery, then your purchasing system ought to be

focused on that, too. It falls on purchasing to communicate to the suppliers what their customers want.”

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17 Jul

Express Air Shipping Still Innovating

Posted in Uncategorized on 17.07.13

When you have no time to waste – when a package or shipment has to get there today, where can you turn?

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Most of us automatically call one of the door-to-door services like United Parcel Service, Federal Express, RPS, and their competitors. These “integrated carriers,” which own and/or operate their own vehicles and aircraft, often are the right ones for the job. But there are other types of expedited services that sometimes are more suitable and more economical.

One option is to use door-to-door courier services. These companies may be local, regional, national, or even international in scope. They operate the local ground portion of a move and contract out with scheduled airlines or other carriers for the long haul. Expedited trucking services, meanwhile, often are the right choice for large shipments. A number of overnight options are available, and some carriers even offer same-day delivery within a certain geographic range.

A third option – and the one on which this article will focus – is to use the scheduled airlines. All of the major U.S. and Canadian airlines offer some kind of expedited package and cargo services. These services “piggyback” on the scheduled passenger flights, using available belly space to move shipments quickly and cost-effectively. Some provide same-day service, while others are “next-flight” services that may deliver the shipment or package that same day or the following day.

Pick Your Flight

usaThe scheduled airlines play a dual role when it comes to offering domestic and cross-border transportation services, functioning both as retailer and wholesaler. They “wholesale” their space to air-freight forwarders, which in turn sell that space to individual shippers. But they also “retail” directly to shippers for certain types of products.

Same-day/next-flight service is one such retail offering. Although they may differ in the details, most same-day services share some common characteristics. They are airport-to-airport services, so shippers and consignees are responsible for delivering the shipment to the airline and picking it up at destination. (Most airlines also offer door-to-door pickup and delivery with advance notice and at an extra charge.) Some airlines have separate offices or counters for their expedited services, while others handle them at their ticket counters or aircargo facilities.

Same-day and next-flight services usually are flight-specific, and most airlines will refund all or part of the freight charges if a shipment does not move on the flight selected. They offer short cut-ofttimes at the point of origin – sometimes as little as 30 minutes before a flight departs – providing an option for last-minute or emergency shipments.

Shipments also are quickly available for pickup at destination. It’s important to note that for international services, the airlines may only deliver import documents to the consignee within the specified time limit. Although the cargo itself may physically be available at the same time, the airlines may not release the freight until the consignee clears the shipment through customs.

Because these services are so time-sensitive, the airlines must place some restrictions on the products being shipped. Many, for example, will not accept individual packages weighing more than 70 pounds or measuring more than 90 inches (length x width x height). Depending on the airline, the aircraft, and the facilities at origin and destination, there also may be restrictions on carrying hazardous cargo, perishable products, and live animals.

Same-day services are appropriate for a wide variety of products. Among the airlines’ regular customers for expedited services are publishers and printers (which ship proof plates and time-sensitive newspapers and magazines); medical-supply distributors (drugs and specialized medications); medical testing facilities (perishable samples and specimens); television and movie producers (film); hospitals and blood banks (organ transplants, blood); the legal profession (depositions, evidence); and banks (canceled checks).

Many of these and other products move via same-day services because of their short shelf life. Companies that depend on Just-in-Time manufacturing processes also are heavy users of expedited airline services, says Richard L. Denhart, director of priority products for American Airlines. The auto makers, for example, all depend on suppliers to deliver exactly one day’s worth of parts each day. If parts aren’t delivered on time or if they come in but prove to be faulty, the manufacturer must receive replacements that same day, he explains. “If they don’t have them, that will result in a shutdown…and that can cost $120,000 an hour or more.”

Weighing the Costs

There are many factors shippers should consider when deciding whether to use an airline or a competing expedited service. Cost is one component, of course. Because the express products “piggyback” on passenger flights, the airlines’ costs are fairly low. As a result, pricing can be quite reasonable. Many airlines charge a flat rate for packages of a certain weight. US Airways, for example, charges $62 for packages up to 50 pounds, $83 for packages weighing between 51 and 70 pounds, and $115 for shipments that weight from 71 to 100 pounds.

For shipments that include more than one package, though, it will be less expensive to use a service that is priced on a per-pound or per-kilo basis than one with per-package rates, advises Zodie Cristakos, manager of cargo marketing for Southwest Airlines. Southwest Airlines and Air Canada, for example, both charge on an aggregate weight basis.

Although “walk-in” prices are reasonable, airlines will negotiate rates for regular customers, says Denhart. Companies such as printers that regularly move large volumes often can work out better pricing, he notes.

Because many times shippers are comparing the airlines’ services to door-to-door services offered by couriers and integrated carriers, it’s important to examine total cost, including local pickup and delivery and time spent on managing the move. “You have to decide how involved you want to get in this process,” Denhart says. “If you already have internal infrastructure like a private fleet or messengers, then it can be better to go directly to the airline.” Shippers that don’t have those kinds of resources, however, may find it more economical to work with a freight forwarder, courier, or integrated carrier, he says.

One of the airlines’ strongest selling points for express service is flight frequency, says Tony LeFebvre, express product manager for US Airways. US Airways, for example, has flights leaving every hour between Washington, D.C., and Boston or New York. Southwest Air, meanwhile, offers 38 flights per day between Dallas and Houston, and American Airlines flies more than 20 times daily between Dallas and Chicago. “[The integrators] can’t match our frequency,” he notes.

With the airlines, shippers also know the exact arrival time (barring weather or air-traffic delays, of course). For critical parts or perishable products, that’s of vital importance. “[Our customers] don’t want to know that it will be there sometime tonight. They need to know that it’s on a specific flight and that it will arrive at a specific time,” says Dave Hinderland, national accounts manager for Southwest Airlines.

With emergency or time-sensitive shipments, control also can be an important issue, says Jim Fisher, Air Canada’s manager, customer service-cargo for the United States. Air Canada, for example, has dedicated personnel meet flights and run documents and packages to express offices or counters. Although the integrated carriers conveniently include customs clearance in their price, there are times when it’s better to do it yourself, Fisher believes. “If shippers use their own customs brokers, they have more influence over how things are handled. The brokers are right at the airport and they can run documents over to customs immediately,” he adds.

What’s Right for You?

Though the airlines’ services offer many benefits, choosing the best option for same-day, next-flight, and other expedited services isn’t easy. Couriers, freight forwarders, and integrated carriers all offer competing services that may be more appropriate for some shippers.

In fact, those companies also rely on the scheduled carriers, putting airlines in the uncomfortable position of competing with their own customers. The airline executives interviewed for this story all emphasized that they considered those companies to be their partners and that each group was trying to meet different needs. “Because we fly during daylight hours, the airlines will always control [the same-day] market,” says Denhart of American Airlines. “But the forwarders, couriers, and integrators are our customers, too, and we will never change that relationship.”

What choice the shipper makes depends on time constraints, the level of service needed, and the total cost. Shippers also must consider the cost of not using an expedited service, as in the case of the auto maker faced with a plant shutdown when parts don’t arrive on time. Finally, the carriers say, shippers that regularly require same-day and next-flight service should look at how best to take advantage of what can be a tough situation. Says Denhart: “The creative companies can take it from being an emergency situation to being an enhancement of their product.”

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15 Jul

Tagging Garbage Has Saved Landfill Owners Millions

Posted in Uncategorized on 15.07.13

The “pay as you throw” age is here as variable rate programs continue to gain momentum across the country, with some areas reducing disposal tonnage by 40 percent. More than 1,000 communities are expected to adopt a variable rate program in 1994.

rftAccountability for trash at the collection point is imperative in any variable rate program or pay-by-weight systems. Radio Frequency Identification (RF/ID) technology answers the problems of accountability for such rate programs. Each resident has one or more roll out carts installed with a transponder or “tag” that contains a unique identification number. This number correlates with a profile on the cart customer which is located in the city database. Profiles can contain information such as name, address, size and color of the cart, rate collection and a chronological history of collection and maintenance over a period of time.

A truck equipped with a transponder reader system automatically reads the transponder when the cart is emptied. A date and time is assigned at the instant each cart is read and sent with the ID to the onboard computer, which the stores the daily route data and batch loads it to the city database at the end of the day or the information can be sent via modem the truck to the city database.

Once the route information is in the main database, productivity criteria may be analyzed. Time and motion studies may be conducted to evaluate truck and driver performance, route assignments, time spent at landfills, transfer stations, maintenance garages and other facilities. Having this information allows a manager to discover inefficiency in the operation. Haulers that own carts and distribute them to their waste customers have found that as many as 10 percent of [the carts] can be unaccounted for over long periods of time or never used after initial distribution. Onboard computers can also record damaged or unused carts along a route.

The Texas Instruments Registration and Identification System (TIRIS) has been installed in almost a million carts in 50 communities. The core of the TIRIS technology is the small, passive (battery-free) transponder attached to the cart. The reader system, which is integrated on the trash truck, sends a low-frequency signal that charges the transponder to enable a return signal with each cart’s unique identification code. The entire process is completed in milliseconds. The read-only transponder contains a factory programmed 64-bit or 20-digit identification code.

Two low-frequency RF/ID system options are available on the market today. Most systems are the full duplex type which is characterized by simultaneous powering of the transponder and transmission of data from the transponder back to the reader. However, since the power and read functions must run simultaneously, the read range of the transponder is reduced. TIRIS uses a half duplex signal that uses sequential powering of the transponder followed by transmission of data to the reader.

Due to the associated cost of implementing RF technology, there has been some initial resistance among the waste industry. To install a $5 transponder on a roll cart and then amortize it over the life of the cart becomes an attractive option given the cost reductions due to increased operating efficiency. Taking five percent from operating costs for a few years will more than pay for the technology and bring waste collection to a higher level.

Once waste haulers and municipal leaders experience the benefits of complete automation there will be no turning back. The RF/ID market in the waste management industry in about to explode as the new competitive edge becomes recognized by all players. profitability will no longer come out of mediocrity in waste operations. As costs continue to rise, new technologies will have to be taken advantage of today to ensure economic and environmental survival in the years to come.

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10 Jul

Designing RF Systems: With The Proper Tools, It’s Easy

Posted in Uncategorized on 10.07.13

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This high degree of integration is especially useful in the manufacture of high-volume products. Items such as cellular and cordless telephones, and wireless LAN equipment benefit from the technology because their product development costs can be spread over hundreds of thousands of units. For instance, Texas Instrument’s TMS320C54x line of DSP ICs have an architecture that has been optimized specifically for use in the baseband sections of wireless terminals and base stations. These low-power (35-100 roW) DSP ICs feature 50 MIPS of processing power. Some also have a hard-wired Viterbi decoding accelerator that reduces a Viterbi “butterfly update” to only four instruction cycles. This addition greatly simplifies channel decoding for applications like GSM handsets and base stations.

Wireless data also is moving into the mainstream, allowing many manufacturers to offer highly integrated solutions. One good example is the SX045 spread-spectrum transceiver, which is offered by American Microsystems Inc., Pocatello, Idaho. Intended for use in wireless LANs which follow the IEEE 802.11 specification, the SX045 contains all the baseband circuitry required for direct sequence spread-spectrum (DSSS) radio. In addition, it performs all radio-control and data-transfer functions of the physical-layer convergence procedure and handles the handshake logic to the physical layer transceiver. A low-cost microcontroller to run the media-access control protocol, a relatively straight-forward modulator/demodulator, and transmitter section are all that’s required for a complete DSSS system.

Above baseband, the move toward integration has been slower, but making substantial advances in the past few years. Achieving integrated RF is not simply a matter of sticking a bunch of fast transistors on a single chip. Some means of matching the impedance between internal elements must still be used. On-chip parasitic effects must be minimized, lest they provide unwanted coupling between different portions of a circuit.

Trench isolation of transistors and careful use of multiple metal layers are only two of the many techniques used to keep crosstalk-induced noise from ruining a chip’s RF performance. Additionally, on-chip passive components are becoming increasingly common on both silicon and GaAs devices. These tiny inductors, capacitors, and resistors are used both for coupling internal devices and for compensating for packaging-induced parasitics on the chip’s inputs and outputs. The same input and output matching networks also are used to raise the RF devices’ impedance to about 50 [ohms], making them less tricky to use.

Integration has done much more than cut the parts count in RF devices. Wireless products using RF ICs often enjoy greatly reduced design times, require much less “tweaking” during unit assembly and testing, and have fewer manufacturing tolerance-induced quality control problems. Both the TQ9143, an integrated 1.4-W, AMPS/TDMA power amplifier from TriQuint Semiconductor, Beaverton, Ore., and the AWT0904, a 35-dBm, GSM/AMPS cellular-band amplifier from Anadigics, Warren, N.J., employ these advanced fabrication techniques. Their on-chip bias and matching networks, and voltage converters significantly reduce the production costs and engineering effort required to produce wireless designs (see Electronic Design, June 24, 1996, p. 87.

Other high-volume applications have led to the development of mixed-signal chips with high levels of digital and analog integration. Functions such as divider networks and control logic can be fabricated on the same chip as voltage-controlled oscillator (VCOs), PLLs, mixers, and even amplifiers. This technique is somewhat easier in the lower-frequency ranges, such as the 49-MHz band used for CB radios, remote-control toys, and cordless telephones.

Motorola Semiconductor, Phoenix, Ariz., is one of the leaders in this area, producing extremely cost-effective chip sets for the very competitive cordless telephone market. One of their latest entries is the MC13110 RF combo IC, a chip that integrates several of the major functions of a cordless telephone into a single IC [ILLUSTRATION FOR FIGURE 1 OMITTED]. Included on the chip are a dual-conversion receiver, a compander, a dual universal PLL, a supply voltage monitor, and a frequency inversion voice scrambler/descrambler security circuit.

Thanks to recent developments, digital technology is no longer limited to baseband applications. Faster analog-to-digital and digital-to-analog converters (ADCs and DACs) are making direct digital synthesis (DDS) of RF signals a possibility for lower-frequency (A-MHz) RF applications. Most converters running above 400 Msamples/s are too bulky and power-hungry for portable applications today, but rapid advances in circuit fabrication will probably see commercially available digital radios passing the GHz threshold before the turn of the century.

These advancements are leading the way for the “software radio,” an all-digital architecture which can be programmed to accommodate any modulation scheme or protocol within its frequency capability. While microphone-to-antenna software radios are not quite a reality today, DSPs are finding their way to the heart of many wireless applications.

While extreme levels of integration can be used for many wireless applications, it is often too costly to implement for all but the commercial products with the highest production volumes.

RF BUILDING BLOCKS

The building-block approach developed by Fujitsu Microelectronics USA, San Jose, Calif., can be used to simplify designs and reduce production costs. Fujitsu has focused on offering its Super Analog component family, a line of smaller, less application-specific integrated “RF building blocks” that can be used in a variety of situations. Currently, their lineup includes the MB5401 integrated low-noise amplifier/mixer, the MB5402 dual low-noise amplifier, and the MB5403 two-stage medium-power amplifier. With a maximum operating frequency of 1.1 GHz, they can simplify both cellular and wireless data applications.

Although current technology does not allow us to apply true functional block-oriented ASIC design techniques to RF circuits yet, Fujitsu does offer a unique “RF Macrocell” technology for speeding up the design process. Known as the Versi-TILE process, it allows designers to work with preengineered bipolar or biCMOS “frames”. The frames contain arrays of transistors, capacitors, and resistors that can be placed on a chip and connected to each other or other frames via two or three metalization layers. There also is a library of predesigned “tiles” which include prescalers, VCOs, buffer amplifiers, and PLLs.

Using the building-block approach, designers can go from supplying a preliminary block diagram to receiving working silicon in eight to twelve weeks. In addition to offering rapid turnaround, Versi-TILE has demonstrated a better than 90% first-pass success rate, based on over 100 designs. If a transition to higher-volume production is desired, the Versi-TILE circuit can be turned into an optimized full-custom design in under six months.

Although these sophisticated chip-level solutions make life much easier, they still can be tricky to use. While component count is sharply reduced, the selection and placement of passives, as well as pc-board layout, are all quite critical. To save designers the task of reinventing the wheel, many RF circuit manufacturers now are offering preengineered reference designs which can be used, at no cost, that can form the heart of a wireless product. In many cases, software for both DSPs and microcontrollers is also supplied. This advantage makes product design a matter of providing packaging, power supply, and custom features that allow for product differentiation.

At its simplest, a reference design includes a components list, schematic, and in the case of an RF device, the all-important pc-board layout artwork. M/A-COM Inc., Lowell, Mass., makes it easy to design its AM52-0001 power amplifier by putting together an evaluation kit containing application notes, a finished 4-layer pc board, all recommended surface-mount passives, RF connectors, and a dc multi-pin connector. Also included in the designers kit is a floppy disk with device performance data and a DXF pc-board layout file [ILLUSTRATION FOR FIGURE 2 OMITTED].

In extremely high-volume markets, chip manufacturers will go to great lengths to make their product easy to use. Analog Devices Inc., Norwood, Mass., has gone so far as to offer a completely certified design for its AD20msp410 GSM cellular telephone chip set. The three-chip solution includes a complete software package that performs all Layer-1 GSM functions. There’s optional software to implement Layers 2 and 3, as well as an application-layer tool kit for developing user interfaces and additional product features. Although it does not sell assembled units itself, Analog Devices went to the trouble of developing a complete cellular telephone design. The design has ETSI type approval, EMI/RFI, and spectral content. Using the preapproved design allows manufacturers bring their products to market in the shortest time possible by eliminating months of compliance testing.

In another case, National Semiconductor, Santa Clara, Calif., is helping electronics manufacturers compete in the highly lucrative market of DECT 1.9-GHz digital cordless telephones by offering a fully developed, type-approved reference design for a full-featured handset and base station. The CompleteDECT solution boasts an advanced RF section with high sensitivity, built-in antenna diversity, ten dialing memories, a 500-m range, a paging function, a 70+ hour standby time, and a 7-hour talk time. Along with a working evaluation unit, the solution includes schematics, parts-lists, pc-board specifications (including Gerber files), shielding specifications, timing diagrams, memory maps, plus test and tuning procedures.

DECT’s simpler cousin, the North American 49-MHz/900-MHz cordless telephone is another market where both cost and time-to-market are critical issues. Recognizing this, Zilog Inc., Campbell, Calif., has developed the ZPhone reference design, a turnkey solution for digital spread-spectrum cordless telephones. Based on its Z87000 and Z87010 baseband chips, and an RF section designed by L.S. Research, Ceadarburg, Wis., the ZPhone design allows manufacturers to produce a product with extended range and high voice quality. The ZPhone is expected to retail for under $140. Both reference designs and complete evaluation kits are available from Zilog.

Harris Semiconductor, Melbourne, Fla., has applied the same formula to its PRISM wireless LAN product line. Recognizing that the IEEE 802.11 wireless LAN standard is a complex, moving target to design products around, Harris has made its 2.4-GHz, 2-Mbit/s, DSSS wireless data system as easy as possible to implement [ILLUSTRATION FOR FIGURE 3 OMITTED]. In addition to a complete reference design, the PRISM chipset’s designers also offer an evaluation kit for prototyping and product development. It consists of two preassembled open-frame PCMCIA transceiver evaluation cards, the PRISM chipset, an industry-standard media-access controller (MAC), RF connectors, PCMCIA extender cards, single-user firmware licenses, diagnostics software, and documentation. If 802.11 compliance is not required, the PRISM system can serve as a platform for the development of customized radios with wider spreading codes and faster data rates which can go as high as 4 Mbits/s.

For one-of-a-kind or low-volume designs, it often pays to completely eliminate all RF engineering by purchasing a complete radio subsystem from another manufacturer, and embedding it in the product. For example, Proxim Inc., Mountain View, Calif., produces the WaveLAN2 product line which allows engineers to integrate a complete wireless LAN subsystem within their products, with a minimum of space, power, or design-time impacts. The unit’s type II PCMCIA card-sized radio data unit is self-contained, requiring only a PCMCIA interface and an antenna connection. RangeLAN cards can be connected conventionally, through an external PCMCIA slot, or embedded within the bowels of its host system. The card’s microminiature coaxial connector, located on its edge, permits an antenna to be attached directly or run to a remote mounting point via a connecting cable. Power consumption (300 mA during transmit) is one of the lowest in the industry, a plus for battery-powered portable applications.

SMARTER DESIGN SOFTWARE

rfdsRF design software has existed for nearly as long as computers, but it hasn’t matured at the same rate as its digital cousin. Some of the lag time is due to the lower demand for wireless systems, but the lion’s share belongs to the richer set of problems faced by the RF engineer.

Traditionally, Spice and various flavors of harmonic-balance analysis were used to analyze circuit designs. Spice-type programs can be very accurate for single-frequency operation, but become cumbersome when attempting to model transient behaviors. Additionally, Spice tends to choke on the non-linear noise response in components such as mixers, amplifiers, and downconverters.

Harmonic-balance software also has been used for highly accurate modeling of RF systems. One drawback with the software is that the simulation load grows exponentially with the number of components or frequencies involved. The result is that modeling non-linear components (which produce lots of harmonics), or circuits with much more than 20 devices, can tax even the most powerful workstation.

While these simple tools can be used to design today’s complex RF systems, it resembles constructing a small computer using stone knives and bear skins. Since design and analysis tools have lagged behind, engineers have relied on brassboard prototypes and other trial-and-error techniques. Of course, this meant at least two or three (and often more) passes were needed to get a design sufficiently debugged for production. It can be time consuming and costly enough for board-level designs, but the 12 to 15 months and three to five spins required for moderately complex RF ICs is nearly intolerable for the development of commercial wireless products.

Over the past few years, RF design software has finally begun to mature, and RF design practices have begun to change with it. Modern RF system design practice typically begins with using system-level behavior modeling tools. These tools are used to model a proposed circuit’s general characteristics, and permit engineers to analyze architectural choices. They could include different schemes for segmenting digital and analog functions. They also could look at the effect of various coding and error-correction algorithms upon the circuit’s overall noise and power characteristics.

A LAYERED APPROACH

Once the overall architecture is nailed down, individual portions of the circuit can be designed using software which works at the device level. After a circuit has been captured, it can be run through a new generation of circuit simulators that operate in the frequency domain. This process makes the analysis of a circuit’s response to complex modulation schemes a much less difficult task. Additionally, new advances in EM simulation allow modeling of the physical characteristics of a circuit, such as package-induced parasitics and the complex impedance generated by circuit board or chip-level interconnect traces [ILLUSTRATION FOR FIGURE 4 OMITTED].

This three-level approach offers many advantages. It permits engineers to make better system-level decisions by quickly exploring more design options before committing to a particular architecture. After detailed design begins, accurate circuit simulation helps reduce the amount of costly and time-consuming trial and error required to debug the design once its actually built (see “Past and future: The new world of RF design,” p, 52).

There are several commercially available RF design software packages which can be tailored to suit many different types of products. The Cadence/Alta group, Sunnyvale, Calif., offers a suite of RF design tools that support both system-level and device-level design and simulation. The software from Alta is used primarily for high-level system definition and analysis, while the Cadence package is focused towards detailed, device- and board-level circuit design and analysis.

At the system level, Alta’s EnWave package is a complete solution, created to specifically address the needs of designers working with wireless communications systems. Some of these systems include PCS, wireless LANs, advanced messaging, satellite communications, and digital cellular standards such as IS-95, IS-136, and GSM. Based on Alta’s core simulation technology, the EnWave package includes application-tuned libraries containing hundreds of algorithmic elements that simulate filters, codecs, amplifiers, modulators, mixers, and all the other elements of wireless systems. The package’s RF library allows designers to model distortions and nonlinearities in systems, to permit rapid trade-off analysis.

Alta’s recently introduced Spectre package also adds the capability to perform whole-chip simulations, including non-linear components. This advance is expected to help cut the number of chip-spins required to produce a working product.

Once a first-cut design is complete, it can be transferred for more detailed fine-tuning within the Cadence environment. While files are not directly transferable between the two systems today, work is underway to develop a seamless interface between the macro and micro design packages.

One of the other major players in the field is HP EEsof. They offer a well-integrated array of RF design tools which include simulation software, element libraries, and device modeling systems. Recently, a new suite of RFIC design tools were released with the intent of shortening the design cycle for RF subsystems. It uses multiple simulation technologies combined with highly accurate device models and efficient optimization algorithms. Even the mechanical properties of the semiconductor chips can be modeled to provide analysis of every aspect of a product’s design.

HP EEsof’s basic suite of RF design tools includes a linear simulator, a non-linear simulator, transient and convolution simulators, a statistical design package, a custom element development kit, and a Spice netlist translator able to import Berkley 2G6, PSPICE, and HSPICE netlists. Linkages to HP’s mechanical design packages and electromagnetic simulation software are available to perform accurate chip- or board-level design and analysis.

CONCLUSIONS

We can expect that wireless applications will be a rapidly expanding market well into the 21st century, and that the demand for engineers with RF familiarity will continue to be high. Fortunately, today’s design tools and products are making it easier than any time since the discovery of the spark gap transmitter to add wireless capability to your next product. While reference design-based RF subsystems take some of the “fun” out of product development, they give the overworked engineer an opportunity to add value to a product by adding functions and features in more visible locations.

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01 Jul

RFID More And More Key For Transport Companies

Posted in Uncategorized on 01.07.13

Radio-frequency tags have become a must for the nation’s rail operations. Now, motor carriers are discovering plenty of uses for tags both on the road and in the yard.

rfA few years ago, radio-frequency (RF) tags or transponders were used only in the rail industry and then, only as a means of tracking rail-cars. Today, however, tags have begun to catch on in the trucking industry, where private fleets and for-hire carriers alike are testing tags to speed up highway inspections and customs clearance and to identify equipment and loads.

Although only a few companies are experimenting with these devices right now, many industry experts believe tags will soon see widespread use. In the near future, they predict, tags will become as commonplace as bar codes when it comes to automatic-identification equipment used in distribution. “This technology is going to [revolutionize] the way some people manage their fleets,” predicts Jim Mathis, a vice president of engineering at trucking software maker Industrial Computer Systems in Evergreen, Colo.

Tale of the Tag

What is an RF tag? Basically, the tag consists of an antenna and microcircuit for data storage. The antenna can transmit the stored information – such as a trailer ID – via radio waves to a reader. Because radio waves are used, a tag reader does not require a direct line of sight to capture and decode information stored on the device.

The tags themselves come in two basic types – passive or active. Passive tags rely on energy from the reader to initiate communication. Active tags, on the other hand, use internal power to send signals to the reader.

Until recently, RF tags could only transmit data to a reader over a short range – often no more than 10 feet. Newer tags have ranges up to 300 feet. Similarly, whereas earlier versions had limited memory for data storage, tags today can have as much as 500 kilobytes of memory, depending on the model. Even with memory and range improvements, tags remain expensive. A top-of-the-line active tag today runs $50 or higher. Tag readers can cost as much as $15,000 apiece.

Despite those drawbacks, the market for radio-frequency identification equipment has grown in recent years. A 1996 Frost and Sullivan report estimated that 1995 revenues for radio-frequency identification device (RFID) technology reached $138.1 million. In part, the steady growth can be attributed to the use of tags to enable electronic toll collection. Vehicles equipped with tags can speed past readers on toll roads, expediting traffic flow while still allowing authorities to collect user fees.

rfidIn the area of commercial transportation, RFID technology was first used in the rail industry. Transmission range isn’t an issue there because readers can be placed alongside the train track in close proximity to passing railcars. As cars speed by, the readers capture information from the tag, noting the time, car location, and direction of travel. In fact, this technology provides the basis for car-location messages used by shippers to track freight.

Right now, some 3.5 million tags made by Dallas-based Amtech are deployed in the rail and intermodal industry. Truck-related applications are forthcoming, an Amtech spokesman says. The company has just begun testing a tag for use as part of a preventative-maintenance program. The new “odometer and identification” tag will relay the time, date, and vehicle’s odometer reading to a host computer. This information then can be used to initiate maintenance at specified mileage intervals.

Yard Work

Beside using tags to keep maintenance records, a number of companies are developing tags to help manage tractors and trailers at a terminal yard. A Virginia-based company, Randtec Inc., has developed a tag with a 128,000-byte memory and a general reading range of 300 feet. Food distributor Atlantic Food Services Inc. in Manassas, Va., worked with Randtec this spring to test the product for yard management. A dozen of Atlantic Food’s trailers were outfitted with Randtec tags and a sensor was installed at the yard gate and on dock doors at the food distributor’s warehouse.

If the sensors do their job of reading the trailer tags, the company will be able to note automatically which trailers arrive or depart from its yard and when they do so. “Our trailer-to-tractor ratio is real tight,” explains David Bunk, transportation manager for Atlantic Food. “The technology allows us to know what trailers are coming in and at what time of day. We can keep a tighter rein on the fleet than someone walking around with a clipboard and piece of paper.”

Savi Technology Inc. of Mountain View, Calif., is likewise developing a tag for truck-fleet yard management. Slated for rollout later this year is a system that creates an electronic record to monitor the movements of tractors, trailers, and even dollies. The tags used in the yard-management system have a range of up to six feet and a memory of 12 bytes.

Skipping the Scales

One of the most innovative applications of tags in the trucking industry is taking place in the western United States. Here, trucks are using tags to bypass weigh stations, where state officials normally stop vehicles to check for compliance with highway regulations. In California, where the program got under way in June 1995, state officials certify trucking companies for participation in the “PrePass” clearance system based on the carrier’s safety record. Once they are equipped with RF tags for vehicle identification, trucks in the program can skip highway weigh stations altogether.

The program, which is operated by a non-profit corporation called Help Inc. based in Phoenix, Ariz., uses transponders and readers manufactured by Hughes Transportation Management Systems in Fullerton, Calif. The Hughes tags have a range that extends up to 300 feet. A computer database developed by Lockheed Martin correlates the individual tag ID information to a specific truck and company.

At the moment, Help Inc. buys the transponders from Hughes and issues them free to participating motor carriers. It then collects a 99-cent fee each time a truck bypasses a weigh station. Walt Keeney, president of the motor carrier Food Express Inc. in Arcadia, Calif., says the time savings justify the cost. “A long-haul driver can only drive 10 hours a day [under federal driving rules],” says Keeney. “If a driver doesn’t have to stop at weigh stations [during the work day], you’ve just [saved] 40 or 50 minutes.”

The PrePass program is quickly expanding beyond California. The program now is under way in New Mexico and Wyoming, and Arizona will offer the program at certain sites later this year.

Eliminating Border Lines

In addition to their role at the weigh station, tags soon could play a major role in expediting the movement of freight across U.S. borders. A number of federal agencies, including the Treasury Department and Department of Transportation, are experimenting with tags to facilitate pre-clearance of cargo at the Mexican and Canadian boundaries. Officials are using Hughes tags for tests on the Mexican border and a transponder made by Mark IV Industries Inc. for tests on the Canadian border.

Similar in concept to the weigh-station bypass program, pre-clearance will allow selected trucks to sail through customs checkpoints. Trucks in the program will be equipped with a transponder that contains a vehicle identification number. When the truck approaches a border-crossing point, a reader will detect its ID and transmit that identification to a computer system that already has received Customs information on its freight. “The system will pull up on the inspector’s screen the info on the cargo and driver,” explains Robert Ehinger, director of International Trade Data Systems in the U.S. Treasury Department. “The system will even include a picture of the driver’s face for verification.”

Tracking the Tags

Despite their vast potential in this area, radio-frequency tags won’t be confined to trucking and rail applications in the future. Another tag maker, Micron, says it’s working on supply-chain applications that will make it possible for companies to mark boxes and pallets for tracking all the way through the distribution channel.

Most industry experts agree that the future for radio-frequency tags is bright. As the word spreads about the benefits of this technology, logistics managers pressed to find new ways to rev up the movement of goods through the distribution channel will surely consider adding tags to their teams.

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