Electronic Design

Test & Measurement: Handhelds

Portable Instruments Have Become A Real Handful
Say the word "handheld," and many of us picture an analog volt-ohm-milliammeter with a set of leads. That's because we've traditionally held meager expectations for instruments we can hold in our hands. We've always thought that handhelds as limited in ability, battery life, and features. But that isn't true any more.

The convergence of many technologies—miniaturization, improvements in active-device performance, advances in batteries, and the extraordinary horsepower in CPUs—are enabling companies that have stayed the course and continue to pursue the marvelous opportunities for developing enhanced handhelds.

Not many others in the T&M cadre are likely to realize the enormous gains in performance and features that handheld designers will realize. Handheld manufacturers are making good use of the latest in battery and CPU innovations, as well as color touchscreens and wired and wireless interfaces. For example, handheld products are burgeoning in applications like physical layer and cable testing.

How large—or better yet, how small—is a handheld? When asked, designers say that if they can get their hand around it or see their hands on both sides, then it's a handheld.

Handheld technology will be on the move, enjoying several significant trends in the year ahead.

Lithium-ion batteries will supplant nickel-metal hydrides and the nicads. Li-ion's ability to provide twice the power at half the weight will dramatically extend operating life between charges and significantly reduce the handheld's overall weight.

Look for handhelds to start sporting memory devices, such as the new 1-Gbit, 2- by 1- by 1/16-in. flash memory cards, which can be simply plugged in. These cards can store hugh amounts of test results. Since this storage is removable, the results can be quite easily transferred between the handheld and other devices equipped with memory-card ports.

Windows CE for handhelds will become more commonplace in handheld devices, dramatically expanding their capabilities and enabling them to do virtually anything a laptop can do.

Expect to see more network troubleshooting gear dressed up in smaller packages. Also, this gear won't need power cords anymore.

Smart handhelds will employ digital-signal processing, supplanting the old dual-slope, analog-to-digital conversion techniques used when digital meter movements were first introduced in handhelds.

Handhelds will play a significant role in hazardous environments because they will be equipped with wireless capability, eliminating the need for a direct connection. Technicians equipped with wireless handhelds will be able to move into the vicinity of a hazard, be it high voltage, high radiation, or otherwise, yet maintain a safe distance. This will be great for checking power factor on high-voltage power lines or measuring voltages, currents, and other electrical and optical parameters.

People are asking for reporting capability. In addition to wireless capability, network interfaces such as Bluetooth, IEEE 802.11b, or IEEE 802.11 will become common on handhelds, allowing users to log into the network. A wireless or wired interface would also provide the handheld access to an ink-jet or laser printer.

Handhelds will be fitted with Ethernet connections. With such an interface, handhelds will assume a number of roles that were never before possible, such as sending instructions to virtually any point in the world accessible over a wired or wireless link. For instance, the instrument could poll sensors of virtually any kind at remote locations worldwide, retrieving voltage and temperature as well as the location and the time the measurement occurred.

Given the current recession, customers for handhelds are more value-conscious than ever. Many users are being called upon to provide their own instruments. Competitive pricing, rather than top-of-the-line performance, is of greatest concern. Though digital instruments have clearly become the prevailing instruments of choice in many domains, look for analog handhelds to continue to play a major role in many price-sensitive applications.

LCD resolutions will continue to improve. Pixels are becoming smaller and more closely spaced, and refresh rates are climbing. Primarily, the demands of mobile phone and PDA designers are driving these improvements. But handheld instrument designers won't overlook such enhancements. They'll be eager to bring these LCD refinements to their products, thereby providing waveform displays that will approach the CRT in quality.

Handhelds Timeline

Simpson Electric Co. introduced the Model 260 VOM, perhaps the most popular VOM ever with over 5 million sold. The current version is the 260-8.

Triplett Corp. debuted the Model 310, the first handheld (palm size) analog multimeter on the market.

John Fluke Mfg. Inc. (now Fluke Corp.) Introduced differential voltmeters, which bring laboratory accuracy to rugged, portable units.

Hewlett-Packard (now Agilent Technologies) introduced the HP 970A probe multimeter, a self-contained, pocket-size instrument that makes high-accuracy voltage measurements.

Fluke's Model 8020A was the first handheld digital multimeter to use analog-digital CMOS and a large-scale LCD.

The latest version of the Fluke ScopeMeter features gigahertz sampling rates, 200-MHz bandwidth, and a color display.

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