Keithley 4200 semiconductor characterisation system
Keithley 4200 semiconductor characterisation system

JUNE 2009: The need for test and measurement (T&M) is across industries. Whether in automotive or manufacturing plants, engineers and scientists need flexible, cost-effective solutions for test, control and design to ensure quality, safety and the most advanced products.

T&M devices are required during the lifecycle of any product, beginning from the design phase to the development phase and later in the production phase. For example, while designing a receiver module, a signal generator is used to provide the necessary signals in order to stimulate a response from the receiver. A spectrum analyser is often used in this setup as the reference receiver, and the results from the test receiver and spectrum analyser are compared. Using these results the design of the test receiver is constantly modified.

One major challenge faced by test engineers is to stay ahead of the technology curve. That is, in order to test the product it is imperative for them to have extensive knowledge of the subject. Given the transient nature of technology, it becomes a real challenge for the test engineers to keep abreast with the new developments and address these applications in an ever-expanding domain.

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Major applications in this digital age
Radical advances in digital technology are forging a globally networked society, bringing huge changes to the electronics industry. Computers, consumer electronics and mobile devices are merging into one always-connected, networked realm, changing the way we communicate, work, play and travel by reshaping our relationship with the world around us.

There are five major application areas in the new digital age for T&M devices: digital RF, high-speed serial data, digital video technologies, embedded system technologies and next-generation network.

Challenges before engineers
The digital-age applications pose many challenges to test engineers. One major challenge is to make the underlying complexity of the next-generation technologies appear simple. This can be achieved through improved functionality, ease of use, greater performance and seamless interoperability.

Digital RF challenge. Digital RF introduces new problems, including runt pulses and broadband transients that cannot be seen with conventional tools. The time spent troubleshooting these problems has a direct impact on the products’ time to market. These problems are often DSP-related, and may not be easily repeatable. If the problem only occurs once a day, being able to capture the state of the device-under-test (DUT) the first time it happens can literally take days to find the root cause.

Engineers need to find spurious signals across a broad frequency range, and these signals are getting smaller and moving faster than ever before. Once the signals are found, they need to get to root cause as soon as possible. To do this, it is necessary to pinpoint the problem in the DUT. Being able to correlate data taken at the time of a failure at multiple points in the design, in multiple domains, is essential to providing rapid insight.

Types of T&M devices

Broadly, the T&M products can be classified into products for general-purpose test and measurement; video test, measurement and monitoring; and communication diagnostics and network management.

The general-purpose test products include oscilloscopes, logic analysers, signal sources and spectrum analysers. Oscilloscopes are the primary general-purpose electronic debug tools. Logic analysers are debug tools used by design engineers to capture, display and analyse streams of digital data that occur simultaneously over many channels. Signal sources are general-purpose stimulus products primarily used in the design and manufacturing of electronic components, sub-assemblies and end products in a wide variety of industries. Spectrum analysers are primarily used in the design and manufacture of electronic components, sub-assemblies and end products that utilise digital RF technology.

Video measurement equipment are used to ensure delivery of the best possible video experience to the viewer, either through traditional analogue television, or through digital terrestrial, satellite, cable or broadband services. These include waveform monitors, video signal generators and compressed digital video test products. They are used in video equipment design and manufacturing, video content production, and video transmission and distribution.
Similarly, network management and diagnostic tools enable network equipment manufacturers and operators to develop, deploy, and manage mobile and fixed-line networks. Network management tools provide continuous performance management to optimise the service performance of an entire communications network. Diagnostic tools test and monitor the signaling protocols in next-generation communication networks and services.

Finally, their budget hasn’t changed. They can buy a spectrum analyser/VSA combination device, or an RTSA, but not both. All the functions of a high-performance spectrum analyser and vector signal analyser must be included in their troubleshooting and characterisation tool.

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Embedded system design challenge. Today, we see a vast array of complex electronic circuits, or embedded system designs, in a wide range of applications—from low-cost to high-performance. The design engineers creating these embedded systems are faced with many of the same design challenges.

Today’s designs often feature many different elements, including microcontrollers or field-programmable gate arrays (FPGAs), serial and parallel buses, analogue-to-digital converters (ADCs), digital-to-analogue converters (DACs) and power supplies, all in a single design. This creates debug challenges for the design engineers.

Designers must monitor a wide range of signals to troubleshoot system-level problems. They may need to trace data flow through their device, requiring them to look at several buses and time-correlate data packets. Or, they may need to troubleshoot a mixed-signal element like an ADC or DAC with both digital and analogue signals. Or, they may need to look at the modulation characteristics of their pulse width modulator. Looking at crosstalk between signals would be another example.

Troubleshooting complex embedded system designs often requires looking at several signals at one time. Tracing data flow through a design may require looking at two 3-wire buses. Troubleshooting an ADC may require looking at an 8-bit parallel bus and an analogue signal. These complex designs often require more than the four channels available on a traditional oscilloscope.

Challenges before test engineers
• Cycle or test time. A whole lot of time is consumed setting up the entire test procedure and creating the test bench
• Verification between design and setup fault
• Fast technological advancements/fast obsolescence
• Cost of equipment/returns on test investments
• User-friendliness/ease-of-use
Some new approaches to tests
• An automated test environment which reduces test times. Users just need to select the particular test and the whole process is taken care by the T&M equipment
• Modular, scalable, software-defined T&M equipment
• One-box solutions with multiple T&M feature sets
• Easy to operate/understand user interface

Designers also need more than just signal visualisation. Serial and parallel buses have become pervasive across applications. In a recent product research, it was found that about 60 per cent of scope users are currently integrating serial buses in their designs. And, about 50 per cent are including parallel buses. The interesting part was that these percentages held true across oscilloscope performance levels—from less than 300 MHz to 2 GHz.

Efficient debug of serial and parallel buses requires automated trigger, decode and search for serial packet content or parallel data. Otherwise, the design engineers are forced to manually decode their signal and to figure out how to trigger on signal characteristics, not data values. Both are time-consuming and frustrating tasks.

Digital video challenge. Digital TV has enabled a series of new delivery mechanisms. The traditional mechanisms of cable, satellite and terrestrial all still exist but are being upgraded to support the delivery of DTV. New delivery mechanisms such as IP for IPTV, the public Internet for streamed video and DVB-H are enabling new broadcasters.

The increasing availability of digital standard-definition and high-definition systems has led to a proliferation of video display formats. Each of these formats has increasing quality and increasing bandwidth requirements. The new video formats for HD TV have driven the need for video to be delivered at higher and higher bit rates. This is similar to the issues with advancing serial data rates.

The architecture of DTV systems has caused a shift away from pure signal integrity measurements to a need to ensure that not only is the signal good but the content contained in the signal is also correct.

Next-generation network. With the convergence of voice, data and video into the latest-generation IP multi-service mobile and fixed networks, the requirements for monitoring and testing networks and elements are becoming more complex every day.

When developing a new network element or testing live network, customers need to be able to troubleshoot any problem and correct it as quickly as possible. With the increasing data rates and amount of information exchanged through the network, the chances for error are greater than ever as are the consequences for their business of a poor service delivery.

The entire telecommunications industry is in a constant state of transition—always moving forward with greater technological discoveries. The customers need a comprehensive unified assurance line that provides integrated, end-to-end monitoring solutions for active troubleshooting, provisioning as well as automated service quality monitoring.

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Wireless/telecom engineers are faced with more signal bandwidth occupied by complex digital modulation schemes and complex antenna arrangements. Here buzzwords like WiMAX, LTE with OFDM and MIMO architecture are example challenges for T&M equipment providers.

Semiconductors. Sizing and scaling pose temperature and self-heating challenges for semiconductor customers, which are tightly linked with demands from research customers. Of course, power consumption plays crucial role, while constantly reducing supply currents. On the contrary is the increasing demand for higher ampere and volt ratings.

What T&M manufacturers have on offer?
The new-age challenges can be met through improved functionality, ease of use, greater performance and seamless interoperability. T&M companies play a critical role in advancing progress on all these fronts. Typically, test engineers face the challenges of reducing development time and costs, increasing productivity, and reducing maintenance and upgradation costs. By combining powerful, flexible software such as National Instruments’ LabVIEW with modular hardware, test engineers can easily build flexible, scalable and customisable solutions that allow them to reduce development time, save costs, increase efficiency and productivity, and design higher-quality products. With this graphical programming environment, they can rapidly and cost-effectively interface with measurement and control hardware, analyse data, share results and distribute systems.

New-generation T&M and monitoring tools help engineers accelerate the performance of computing and networking through high-speed serial technologies; apply digital RF technologies to create flexible wireless networks and mobile devices; incorporate embedded systems that are becoming pervasive; and facilitate the rapid proliferation of high-quality video through multiple digital formats and channels.
For instance, Tektronix claims to have come up with a new generation of measurement tools including the world’s fastest, most capable oscilloscopes, logic analysers for real-time digital systems analysis, the world’s first real-time spectrum analysers capable of visualising a live RF spectrum revealing signal anomalies, the fastest arbitrary signal sources to test design margins, mixed-signal oscilloscopes useful for embedded designs, the most complete set of video solutions (from content production to automated content quality control, and monitoring of video transmissions to ensure the best possible viewing experience), and network diagnostic and management solutions that cover fixed, mobile, IP and converged multi-service networks.

As the bandwidths used are increasing, the T&M instruments should be capable of handling high-bandwidth applications. Most of the customers in the telecom sector work on multiple technologies at a time, so the T&M instruments have to provide the facility to upgrade and install new options easily. These also need to be equipped with a selection of interfaces like GPIB LAN and USB to facilitate connection with other instruments; e.g., for remote control.

Wireless/telecom solutions need software-defined-radio (SDR) architecture with typical signal bandwidth of 40 MHz and modular instruments supporting multiple input/multiple output (MIMO) configurations, hence putting different RF sources and analysers tightly synchronised together. Of course, all this needs to be supported with a powerful GUI and user software.

Keithley offers vector signal analysers 2800-series and vector signal generators 2900-series with signal bandwidth of 40 MHz (80 MHz), ranging up to 6 GHz. Both instruments are configurable in MIMO systems up to 8-by-8 (eight analysers and eight generators). A powerful software package for signal generation, analysis and simulation complements the offering.

Agilent U1253A true-RMS OLED multimeter
Agilent U1253A true-RMS OLED multimeter

For semiconductors, the major challenges are integrated pulsing, while eliminating self-heating effects, a wide dynamic measurement range from femto-amperes to 10’s of amperes and similar dynamic measurement ranges for voltages.

Keithley has developed Source Meter 2600A Series, which supports pulsing with range of different ampere and volt ratings. Or, the 4200-SCS semiconductor characterisation system, which supports pulsing, with integrated scope and capacitance-voltage measurement function. All instruments can be integrated under a powerful GUI called ‘advanced characterisation suit.’

Good Will Instrument has announced powerful and affordable GDS-1000A series DSOs featuring 1GSa/s sampling and 2M point memory. The family of three includes the members of 60MHz, 100MHz and 150MHz bandwidth, respectively. Without a tedious menu tree to deal with 2M point memory waveform, GDS-1000A gives a user-friendly operation procedure to expand any part of the waveform and display it in detail on the screen. Just use the horizontal position knob to move the zoom range sideways, and time base knob to change the zoom range. Press ‘window zoom’ and the expanded waveform is there.

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Yokogawa claims to be the only company in the world to provide 8-channel, 500MHz DSOs. Its WT200 series digital power meters measure low powers, making them suitable for sub-watt applications like solar, LED panel, automotive, robotics, fuel-cell and space technologies.

Significant trends
As the global economic climate places additional constraints on budgets, test engineers are challenged to identify ways to test devices more efficiently than ever before. National Instruments has identified three trends—software-defined instrumentation, parallel processing technologies and new methods for wireless and semiconductor test—that will significantly improve the efficiency of test and measurement systems in 2009. These trends help engineers develop faster and more flexible automated test systems while reducing their overall cost of test, and companies worldwide and from all industry segments are seeing significant benefits from applying these methods and technologies.

Engineers are using software-defined instrumentation to achieve new levels of measurement performance and lower test costs by applying the latest technological advancements such as multicore processing and FPGAs in their test systems to meet the demands of new application areas such as wireless and protocol-aware test. The quick return on investment from these benefits is contributing significantly to the mainstream adoption of software-defined instrumentation.

Major contributors to this report
1. Klaus Leutbecher, managing director-Europe/India, Keithley Instruments
2. Jayaram Pillai, managing director for India, Russia & Arabia, National Instruments
3. Yatish Mohan, managing director and head, Rohde-Schwarz
4. Naresh Narasimhan, country marketing manager, Tektronix India
5. Gautam Awasthi, general manager-marketing, Electronics Measurement Group, Agilent Technologies
6. Vasudev Tantry, general manager, Anritsu India Branch Office
7. Sandeep Sharma, DGM-operations, The Tinsley Group Ltd (India)
8. R. Thirumalaisami, head of test and measurement for Yokogawa test & measuring products, Yokogawa India
9. Anil G. Chowta, director, FALCON
10. Thomas Lin, application engineer-marketing department, Good Will Instrument Co.
11. Rajan Arora, team leader (testing), Barco Electronics Systems
12. Zakir Hussain, CEO-Instruments Division, Glorious Electronics
13. Wayne Kerr Electronics

By making test and measurement devices software based one can do a lot more with them than otherwise. Software adds innumerable advantages such as flexibility, customisability, scalability, re-use, ease of use, low maintenance, faster development, reduced time-to-market, and all this contributes to reducing engineering costs in many different ways. More and more features and capabilities are being added by upgrading the device software rather than the hardware. This helps in keeping the costs down.

Consistent hardware and software concept. The reuse of the tester hardware, tester software and test routines in all phases of the development process—from the first software module test to the conformance tests and regression tests, as well as for optimising performance, delivers optimum results.

Better test coverage through automation. Most tests can be fully automated if necessary. This approach allows users to perform a large number of tests for the various versions of the mobile phone software. This increases test throughput.

Multitechnology solution. With mobile phones supporting several technologies on a single device, it is desirable that the testing equipment also support multiple technologies on a single box.

The future
For most of the general-purpose measurements the old instruments work just fine. But for testing new applications, which place a stringent requirement on such parameters as power, bandwidth and speed, the design engineers will need to upgrade to new instruments.

A migration is expected from older T&M technologies to newer and more advanced technologies. One example is LXI or LAN extension for instrumentation slowly replacing GPIB or general-purpose instrumentation bus. There is a natural application space for new instruments, e.g., semiconductor technologies, nano and organic materials, solar cells and MEMS to name a few.

Companies will move towards availing T&M services rather than purchase of T&M. Most of the T&M manufacturers are not geared up to meet this requirement as this would require a major shift in their policy of approach to the market.

If we talk about sales and marketing of T&M instruments, the concept of mall-like experience is being introduced by T&M providers like Glorious Electronics. Unlike the typical ‘instruments-selling shops’ where the client is supposed to have already made a choice, or is purely guided by the ‘lowest cost’ syndrome without understanding the application or need, here he is guided and provided with a demonstration if necessary.


The author is a deputy editor at EFY

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