[Engineering Feature] Radio Interoperability—It's Harder Than It Looks
Emergency management can be difficult enough. Designing the systems that provide seamless communication between personnel presents some equally tough challenges. Fire swept through the hills above the cities of Berkeley and Oakland, Calif., on Oct. 21, 1991. Known as the Tunnel Fire, it destroyed more than 2800 homes and damaged almost 700 more. It also burned some 1500 acres. And while it caused $1.5 billion in damage, its worst toll reverberated in...
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Don Tuite
[Technology Report] Software Rules The Day In Multicore SoC Design
Looking back over the past 10 years or so, semiconductor process technology more or less kept pace with the demand for functionality in large-scale processor-based ICs. When the next-generation set-topbox IC needed more horsepower, a move from, say, a 180-nm process to 130 nm would provide the necessary boost by adding gates and the ability to run faster clocks. But that next-gen chip would still carry a single processor. Things have changed dramatically...
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David Maliniak
[Leapfrog: First Look] SDRAM Chip Set Boldly Goes Where No Man Has Gone Before
When it comes to achieving more memory in the same amount of space, we typically talk about process shrinks, die stacking, multichip packaging, and other techniques. But MetaRAM, a fabless company that recently “de-cloaked,” has shot its new DIMM-based SDRAM torpedoes into the market and scored a direct hit. Web 2.0-type applications are causing bottlenecks in memory usage. Also, processing power is doubling every 18 months while DRAM capacity doubles only...
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Daniel Harris
[Design View / Design Solution] Bridge Architecture Solves Performance, Design, Cost Problems In New Portables
Interconnecting peripherals and mass storage to embedded processors has always been a challenge, but now it’s an even more critical part of designing portable devices. Designers must solve numerous problems, such as power consumption, data speed, and configuration flexibility, while minimizing parts count and cost. One solution that bears consideration is the West Bridge, a fast interface solution that can simplify many embedded portable designs. The...
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Danny Tseng
[Ideas For Design] Circuit Transfers Resistance Value Through Isolation Barrier
The circuit shown in the figure can monitor resistance in a noisy or otherwise hostile environment. A 1:1 transformer provides isolation and a good common-mode rejection ratio (CMRR). The resistance across the secondary winding is reflected to the primary, where it forms a voltage divider with resistor R1 (see the figure). This divider produces a reducedamplitude clock signal that's coupled through C2, rectified by ...
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Leo Sahlsten
[Ideas For Design] Novel Switch Interface Scheme Reduces Microprocessor Pin Count
The most common method for interfacing multiple switches—multiplexing— allows for the connection of (N/2)2 switches with N microcontroller IO lines. The method described below, which has its roots in an LED interface technique commonly known as “Charlieplexing,” makes it possible to interface N*(N – 1) switches with N IO lines. In conventional multiplexing of an N-by- N matrix with 2N IO lines, half of the lines are configured for input and...
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Kartik Joshi
[Ideas For Design] Electronic Birthday Candles “Blow Out” One At A Time
This circuit creates a set of LED-based electronic birthday candles that are just as much fun as blowing out wax candles, but are also reusable, scalable, and even eco-friendly. It uses a thermal sensor that’s maintained at a temperature above the ambient temperature. When you blow air over the sensor, the resistance changes. The circuit detects this change and turns off the eight LEDs. When you stop blowing, all but one of the LEDs turn on. This cycle...
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Abhijeet Deshpande
[POV: Point Of View] High-Speed Serial Data And RF Wireless Dominate Today's T&M
Two key areas of electronics are driving the development of new test and measurement (T&M) instruments—high-speed serial buses and wireless test. Both require very high-frequency capability as well as the ability to support the many standards that are being developed. CIRCUITS AND PACKETS There is a movement in digital design, from parallel bus structures to serial buses at microwave frequencies, with the growing set of T&M...
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Carla Feldman
[Editorial] Turning Buses And Trucks Into Hybrid Vehicles
I recently had a chance to visit Odyne Corp., a sevenyear- old company based in Haupauge, N. Y. It develops plug-in hybrid electric power trains for medium and heavy-duty vehicles. While I was there, I met with its director of engineering, Dana DeMeo. I had worked with Dana when he was in college. His expertise then was in repairing all sorts of electronics equipment for his college buddies. Now, he’s in charge of developing the embedded system that controls the...
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Joseph Desposito
[Pease Porridge] Bob's Mailbox
HELLO BOB, A note concerning electric cars and plugin hybrids: Consider that politics has little to do with engineering and/or science. It only pays lip service at those altars. So, somebody has to do serious planning for the immediate future. I’ve been working on some serious battery-charger designs. One of our planners (an engineer) did some research in good old California. We learned that your utility companies have ...
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Bob Pease
[TechView: Analog & Power] Single Chip Digitizes High-Side Power Measurements
Single Chip Digitizes High-Side Power Measurements In-circuit power measurements frequently involve a currentsense amplifier or a hot-swap controller and an analog-todigital converter (ADC). Optimally, the current sensing is done on the high side of the load to avoid false grounds. But one problem with that approach is the presence of a high common-mode voltage on the amplifier input. Another is the typical ADC’s limited input voltage range. In addition, the cost of...
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Don Tuite
[TechView: Analog & Power] Monolithic Ultrasound AFEs Usurp Multiple Chips In New Designs
There are now two sources of analog front ends (AFEs) for ultrasound applications. Texas Instruments is sampling the AFE5805, the first member of a future family for portable to high-end ultrasound diagnostic equipment. Last year, Analog Devices introduced the AD9271 for the same market. Functionally similar, both are octal devices that incorporate a lownoise amplifier, variable gain amplifier (VGA), anti-aliasing filter, and 12-bit analog-to-digital...
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Don Tuite
[TechView: Communications] Superior Dispersion Compensation Paves The Way For 40- And 100-Gbit/s Fiber Transmission
The primary limiting factor in transmitting very high data rates on fiber-optic cable is signal dispersion. Dispersion is the lengthening of a pulse over distance due to the variation of the speed of light through the fiber at different wavelengths. Also called chromatic dispersion, it can be minimized but not eliminated. However, designers can compensate for it. Dispersion is holding back the deployment of 40- and 100-Gbit/s fiber transmission systems. As Internet traffic grows and...
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Louis E. Frenzel
[TechView: EDA] Design Flow Halves Development Time For Mixed-Technology PCBs
Once found chiefly in the military and aerospace domains, printed-circuit boards (PCBs) with a mélange of analog, digital, and RF circuitry are now everywhere. In fact, the wireless telecom and consumer sectors are embracing them wholeheartedly. But that doesn’t mean they’ve gotten any easier to design. Mixed-technology PCBs are only growing in density and complexity, encompassing more layers than ever, multiple power domains, and greater sensitivity...
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David Maliniak
[Engineering Essentials] Storage Must Prepare For The Zettabyte Universe
Remember when bubble memory was the top storage technology? Then along came the faster, cheaper, and higherdensity hard-disk drive (HDD). Of course, bubble memory replaced core memory. One example of the latter was the Apollo Guidance Computer, which incorporated the read-only core rope memory (it resembled a rope of woven copper wire). The Apollo 11 lunar mission in July 1969 used 36 kwords of core rope memory ROM with a cycle time of 11.7 µs to...
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Daniel Harris
[EEPN In Electronic Design] Please Touch! Explore The Evolving World Of Touchscreen Technology
You’ve probably encountered some faulty touchscreens that required multiple touches, applying more pressure each time, just to register an entry. That’s because early resistive touchscreen technologies were environmentally unstable and subject to a variety of wearout mechanisms. Today’s touchscreens, however, are a joy to use. Their technology underpins attractive and responsive interfaces that are easy to modify for additional functionality. Modifications...
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Hal Philipp
[EEPN In Electronic Design] Unique Technology Boosts Image Quality Of Low-Cost Cameras
Two key areas of electronics are driving the development of new test and measurement (T&M) instruments—high-speed serial buses and wireless test. Both require very high-frequency capability as well as the ability to support the many standards that are being developed. CIRCUITS AND PACKETS There is a movement in digital design, from parallel bus structures to serial buses at microwave frequencies, with the growing set of T&M...
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Mat Dirjish
[Lab Bench] A Visionary Passes, But The Dream Survives
The recent death of sciencefiction author Arthur C. Clarke has been noted widely by the conventional press. But I wanted to take the time to reflect on his impact on our industry. Clarke joins the ranks of sci-fi writers like Isaac Asimov and Robert Heinlein, whose dreams remain alive because of their books. I’d bet only a few of you haven’t read at least one of his short stories or novels. Shades of the HAL 9000 supercomputer from his 2001: A...
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William Wong
