Wednesday, January 14, 2009

Analog Dialogue Scavenger Hunt

Match each of the following clues with an article published in Analog Dialogue during 2008. The clues are intended to be somewhat obscure. For example, if the clue was "Don Adams meets Kermit the Frog," the correct answer would be Smart Metering Technology Promotes Energy Efficiency for a Greener World, keying on the words smart and green. A list of all articles published in 2008 has been included for your convenience.

One randomly chosen entrant will receive a Celestron SkyScout Personal Planetarium, which uses Analog Devices accelerometers to locate and identify objects in the sky, plus eternal recognition on Analog Diablog.

Please submit all entries to
by Monday, February 2, 2009.


A. Some maids don't do them

B. This armor pushes buttons

C. What was Kirchhoff's previous law?

D. Can you hear me now?

E. Not a retinal scan

F. Catch an octopus

G. Time for a low-cost antacid

H. Superfund site

I. Think about rabbits

J. Synchronize watches

K. A good ruler

L. IP for better remote controls

M. Leftovers again?

N. Rein in the leaders

O. Trading stolen goods

P. They need to be saved

Q. Is it loud in here?

R. More than one necklace

S. In-situ updates

T. Open your heart

U. Try these hot dogs

V. Now we're cooking with gas. Not!

W. Set that output straight

X. Stay on track


1. Analog Front End for Femto Base Stations Brings Wireless Connectivity Home

Imagine a device that can provide high-quality cellular reception within your home, allowing you and your family unlimited voice and data usage for a low monthly fee. A femto base station, usually referred to as a femtocell, provides all that and more. This small wireless device, which improves local wireless coverage when placed in a home or office, is poised to dramatically change the wireless infrastructure landscape.

2. Considering Multipliers, Part 1 [The Wit and Wisdom of Dr. Leif-7]

Multipliers exploiting translinear loops, current-mirrors, current conveyors, and linear gm cells continue to be indispensable more than sixty years since the very first fully monolithic ICs were fabricated in 1967. In this futuristic tale, Drs. Newton Leif and Niku Chen discuss multiplier topologies, uses, and history. Leif also provides some hints as to how neurons, which are translinear, behave exactly like bipolar junction transistors.

3. Design, Simulate, and Document Proprietary Wireless Systems

The broad acceptance of standards developed for short range wireless connectivity has been one of the notable features of the semiconductor market in the past few years. These standards include Bluetooth, various flavors of Wi-Fi, ZigBee, and new emerging standards, such as Wibree/Bluetooth ULP and Ultra Wideband. The available wireless standards are not always the best fit for the application's requirements, however.

4. Maintaining Public Railways with Lower Cost and Improved Safety

A new, systematic maintenance approach now makes it possible to measure, locate, and fix rail- and tramway defects when they appear. Mature railway-engineering know-how and cutting edge technologies—including Blackfin processors and graphical system design techniques—combine to improve and optimize public transportation. This can result in longer operation lifetimes for rails, improving economy and reliability.

5. Impedance Measurement Monitors Blood Coagulation

Blood coagulation is a complex process by which clots are formed to end bleeding at an injured site. During heart-bypass surgery, blood is diverted to a heart-lung machine. An anticoagulant is administered during surgery—followed by a rapid reversal. This article describes a coagulation monitor that provides rapid, automated data—aiding patient safety, workflow, and decision making—and leading to improved outcomes.

6. Fingerprint Sensor and Blackfin Processor Enhance Biometric Identification

The need for effective, efficient security is manifest in today's world. Individuals must be identified to allow or prohibit access to secure areas—or to enable them to use a computer. Biometric signatures identify individuals by measuring unique physical and behavioral characteristics using: a sensor, feature extraction, pattern matching, and decision making—allowing a user's claimed identity to be authenticated or rejected.

7. Noise Figure and Logarithmic Amplifiers [The Wit and Wisdom of Dr. Leif—6]

Log amps are uniquely equipped as RF measurement elements at frequencies from near-dc up to 12 GHz because of their wide dynamic range, temperature stability, excellent log conformance, and ease of use—with measurements provided directly in decibels. Noise figure is a valuable metric when log amps are used in the signal path, as it indicates the system's ability to extract information in the presence of noise.

8. Understanding Hot-Swap Controllers: Hot-Swap Circuit Design Example

High-availability systems, such as servers, network switches, redundant-array-of-independent-disk(RAID) storage, and other forms of communications infrastructure must be designed for near-zero downtime throughout their useful life. Components that fail or need updating must be replaced without interrupting the rest of the system. This process, known as hot-swapping or hot-plugging, requires a hot-swap controller.

9. Discrete- and Integrated Control of Power Amplifiers in Base Stations

In wireless base stations, the power amplifier dominates the performance in terms of power dissipation, linearity, efficiency, and cost. Monitoring and controlling the PA makes it possible to maximize the output power while achieving optimum linearity and efficiency. This article discusses the elements of a monitoring-and-control solution for the PA using discrete components—and describes an integrated solution.

10. Cooking Inductively: ADI iCoupler Technology Isolates Hob and User Interface

Easy-to-use inductive cooking surfaces (hobs) are significantly safer, without flames or other direct heat sources on the hob. They have better overall performance, including faster heating time, and are gaining acceptance by consumers as they are becoming more affordable. Designing the circuitry that drives the inductive plate to heat metal pots requires an understanding of a wide variety of physical principles and techniques.

11. Analog/Digital-Converter Clock Optimization: A Test Engineering Perspective

The entire system-clock signal chain must be understood in order to achieve optimal performance from an A/D converter. It can be discouraging to find that a circuit's accuracy is clock-jitter limited, as this problem could have been prevented during the design phase. Decreased clock jitter can be achieved through frequency division, filtering, use of an improved clock source, and proper choice of auxiliary hardware.

12. High Side Current Sensing: Difference Amplifier vs. Current-Sense Amplifier

Accurate high-side current sensing is necessary in applications such as motor control, solenoid control, and power management. In these applications, monitoring the current on the high side permits improved diagnostic capabilities and maintains the integrity of the ground path by avoiding the introduction of shunt resistance. The sensing circuitry must reject high common-mode voltages, while providing high gain and high accuracy.

13. 8-channel data-acquisition system

The principal factors that affect data acquisition systems are: speed, accuracy, power dissipation, package size, and component cost, with varying factors becoming critical depending upon the application. A single op amp can be used to drive the ADC in an 8-channel data-acquisition system, reducing the cost and size of the overall system.

14. Multi-Voltage JTAG Chain

As low-power, handheld devices become more prevalent, printed circuit boards with a mixture of 5-V, 3.3-V, 2.5-V, and 1.8-V devices have become common, making the design of a JTAG chain challenging. The designer must determine both the operating voltage and the order to place devices that operate at different voltages. This article provides some tips and techniques for making a robust design.

15. Residual Noise Measurement Extracts DUT Noise from External Sources

Residual phase noise measurement cancels the effect of power supplies, input clocks, or other external noise sources. This article highlights the attributes of the residual phase noise setup and demonstrates how additive phase noise can be used to identify the source of noise-related issues.

16. Implementing In-Application Programming on the ADuC702x

The ADuC702x Precision Analog Micro-controller provides a serial downloader for loading an assembled program into on-chip memory, but this requires a user to manually tie a pin low during reset or power on. In-application programming allows upgrades without touching the board. This article provides an easy method for upgrading programs.

17. Adding Test Capability to a Window Comparator

It probably wasn't too long after comparators were invented that someone thought to put two of them together to make a window comparator. This article shows how to add an externally controlled test function to a window comparator in order to test whether the circuit is working properly or not.

18. Protecting Off-Amps

The best reason to be an applications engineer is the wide variety of customers, applications, circuits, and questions encountered, all of which provide daily opportunities to learn something new. Each year I receive several questions regarding the kind of performance users might expect from our amplifiers when their power supply is off. I like to refer to these amplifiers as "off-amps."

19. Linear Variable Differential Transformers

The linear variable differential transformer is an accurate and reliable method for measuring linear distance. LVDTs are position-to-electrical sensors whose output is proportional to the position of
a movable magnetic core, which moves linearly inside a transformer. LVDTs find uses in machine-tools, robotics, avionics, and computerized manufacturing.

20. Open-Loop Calibration Techniques for Digital-to-Analog Converters

In principle, you give a digital input to a DAC and it provides an accurate output. In reality, the accuracy of the output voltage is subject to gain and offset errors from the DAC and other components in the signal chain. The system designer must compensate for these errors in order to get an accurate output voltage.

21. AC Shield Enhances Remote Capacitive Sensing

The principle of a user touch causing a capacitance change to activate a switch is well understood, but implementing a PCB sensor design with proper shielding and routing poses a challenge. Analog Devices provide a complete capacitive-sensing solution, including controller, evaluation tools, sensor design libraries, and software for the host microcontroller.

22. Inexpensive High-Speed Amplifiers Make Flexible Clock Buffers

Consumer electronics, which tends to be lower frequency and less demanding than typical clock buffering applications, can use inexpensive high-speed op amps as an alternative to traditional clock buffers. High-speed amplifiers are less expensive than traditional clock buffers, yet can accommodate a wide range of designs.

23. The Contaminator of Signals: HF Common-Mode-Generated Errors

High-frequency common mode exists everywhere. When people are working, high-frequency trash is being generated. Its presence may be recognized by the mysterious errors it generates, but these errors are frequently blamed on thermal effects that almost never exist. Even transducers and their excitation supplies are subject to this error source.

24. BIST for Analog Weenies

Built-in self-test (BIST), once reserved for complex digital chips, can now be found in devices with relatively small amounts of digital content. The move to fine-line process geometries has enabled data converters to include BIST functionality. This allows hierarchical test strategies to be implemented, providing a powerful feature for enhancing system reliability.

Dan Sheingold - Editor
Scott Wayne - Publisher and Managing Editor

Tuesday, January 06, 2009

Equalization and Pre-Emphasis Enable Use of 30-m Cat-5 UTP Cable

The use of the category-5 unshielded twisted-pair cable has grown due to
its respectable performance and low cost. Currently being used for
keyboard-video-mouse networking, this type of cable provides an
inexpensive solution for connecting HDTV components when long-distance
connectivity is required.

Low-Cost Video Multiplexing Using High-Speed Amplifiers

The large number of video sources connected to a single display makes
video switching a requirement in home and automotive entertainment
systems. In the home, the set-top box, DVR, VCR, DVD player, video game,
and PC all feed one display. In cars, the rearview camera, DVD player,
navigation system, and auxiliary devices all feed the display.

Smart Metering Technology Promotes Energy Efficiency for a Greener World

We’re all familiar with the electricity meter in the garage or basement.
We may even have looked at it once or twice to phone an up-to-date
reading to the utility company in place of an estimate. Thanks to
technology, a quiet revolution is taking place inside this innocuous
looking meter. This article describes how automatic meter reading and
the smart grid can help improve energy efficiency and reduce carbon