Modern Test and Measure: June 2014

June 2014

Interview with

Aart Konynenberg

Manager, Emerging Business Unit Anritsu

Building a Better Test Bench New Oscilloscope User Interfaces

Anritsu’s COMMUNICATION

INSTRUMENTS Pass the Test

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be at the top of your shopping list.

However, if you don’t need a DMM’s AC measurement capabilities and have limited bench or rack space available, a source measure unit (SMU) instrument is a great alternative. An SMU can serve the functions of both the DMM and power supply because it allows simultaneously sourcing voltage and measuring current or vice versa.

Modern Test & Measure

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What levels of resolution and accuracy are appropriate for my applications?

voltage or current measurements may demand greater sensitivity than a DMM can offer, so think about investing in a nanovoltmeter, picoammeter, or electrometer. Another important selection consideration is an instrument’s ability to adapt to new test requirements, which can help prevent premature obsolescence.

CONTENTS

If your application requires a critical degree of resolution, accuracy, and e sensitivity, then certainly allocate yo budget to get the right tools. But mo applications don’t require extremes of either resolution or accuracy and spending money to achieve them sim makes it more difficult to afford essential equipment.

Figure 1. Source Measure Unit (SMU)

Keithley 2450 Advanced

TECH ARTICLE

instruments integrate the capabilities of Touchscreen SourceMeter Every piece of hardware and a precision power supply with those of software on the bench can make a high-performance DMM in a single For one thing, the probe’s lead length will instrument. SMU instruments can a substantial impact on your present some amount of inductive loading to the simultaneously source or sink voltage input ground leads, as shown in an equivalent productivity. Does it offer the circuit diagram of a probe input (Figure 2). The while measuring current, and source or sink ground lead is the primary return path for current current while measuring voltage. They can right interfaces to allow easy that results from the input voltage acting with be used as stand-alone constant voltagethe or probe’s input impedance. The ground lead integration into a benchtop constant current sources, as stand-aloneand input lead’s inductances combine with system with other hardware voltmeters, ammeters, and ohmmeters, the probe’s input capacitance to form a series LC network. That network’s impedance drops and as precision electronic loads. Their high on the bench? Does it Maliniak make it substantially at its resonant frequency, and this

By David performance architecture also allows using effect, known as ground lead corruption, is the Technical Marketing Communication Specialist simple to store data and them as pulse generators, as waveform cause of ringing often seen after the leading Teledyne LeCroy generators, and as automated current- edge of pulses. retrieve it when needed?

The Realities of Oscilloscope Probes Building a Better Test Bench

How can ground lead corruption be allevia One way is to raise the resonant frequency LC network by decreasing the inductance, capacitance, or both. Realistically, because input capacitance is already very low, the o option is to reduce the input inductance. T

achieved by using input and ground leads t are as short as possible.

Capacitive loading can be a difficult nut to as it can affect rise-time, bandwidth, and d measurements. At high frequencies, capac loading can affect the amplitude and wave of measured signals.

voltage (I-V) characterization systems.

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Looking for a good, albeit very expensive, paperweight? Try using an oscilloscope without probes! Probes are often taken for granted, but they are one of the most critical elements of the signal chain in any test scenario.

TECH ARTICLE

Ideally, an oscilloscope probe would make contact with the circuit under test and transmit its signal from the tip of the probe to the instrument’s input with perfect fidelity.

We would like to see the probe exhibit zero

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Input ca

Input

The Realities of Oscilloscope Probes Circuit

attenuation, infinite bandwidth, and linear phase characteristics at all frequencies.

The circuit under test has its particular electrical characteristics for a given signal, which are what we want to measure. Alas, the probe itself is a circuit with its own electrical characteristics.

When the probe tip meets the circuit under test, their characteristics combine in a way that can affect the measurement results. The probe’s

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Input inductance

input impedance will be introduced into the circuit. All probes present some amount of resistive, capacitive, and inductive loading that must be accounted for.

ground

Figure 1: Teledyne LeCroy's ZS2500 high-impedance active probe

Input resist Ground lead inductance

June 2014

Figure 2: Probe input equivalent circuit

COVER INTERVIEW Interview with Aart Konynenberg

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Manager, Emerging Business Unit, Anritsu

TECH ARTICLE

Building a Better Test Bench

New Oscilloscope User Interfaces

New Oscilloscope User Interfaces

Interview with

Aart Konynenberg

Manager, Emerging Business Unit Anritsu

Anritsu’s COMMUNICATION

INSTRUMENTS Pass the Test

3

Modern Test & Measure

Keithley 2450 Advanced Touchscreen SourceMeter

4

TECH ARTICLE

Building a Better Test Bench Starts with Asking Yourself the Right Questions

By Jonathan Tucker Keithley Instruments, Inc.

A

recent conversation with one of our applications engineers about a call from a customer looking for guidance on equipping a new test bench started me thinking about the decision-making process electrical engineers (EEs) go through in allocating their limited hardware and software budgets. How can they feel confident that they’re using those dollars wisely?

To me, a buyer’s first step should always be to evaluate his or her test and measurement needs as a whole, rather than as a series of discrete buydon’t-buy decisions. The best way to avoid buying an instrument that ends up on a shelf rather than making measurements is to take the time needed to establish all the application’s requirements before browsing through a vendor’s catalog or website or asking a sales rep to call. Essentially, it comes down to asking oneself the right questions.

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Modern Test & Measure

What’s missing from my basic toolbox?

Every EE on the planet needs four basic tools in his or her toolbox: an oscilloscope (to visualize an electrical signal), a digital multimeter or DMM (for general-purpose measurements of DC voltage and current, AC voltage and current, and resistance), a power supply, and a waveform or function generator. Plenty of organizations have extensive equipment pools from which to draw these instruments, but if yours doesn’t, these four need to be at the top of your shopping list.

However, if you don’t need a DMM’s AC measurement capabilities and have limited bench or rack space available, a source measure unit (SMU) instrument is a great alternative. An SMU can serve the functions of both the DMM and power supply because it allows simultaneously sourcing voltage and measuring current or vice versa.

Every piece of hardware and software on the bench can make a substantial impact on your productivity. Does it offer the right interfaces to allow easy integration into a benchtop system with other hardware on the bench? Does it make it simple to store data and retrieve it when needed?

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What kinds of applications am I working on now? What about a few years from now?

For some applications, the basic four instrument types can’t cover all the bases. For example, an SMU is a fourquadrant instrument, so it’s a wise addition for applications that require both sourcing and sinking power, sweep-mode sourcing, load testing, or that demand tight integration between source and measurement (Figure 1). Similarly, extremely low voltage or current measurements may demand greater sensitivity than a DMM can offer, so think about investing in a nanovoltmeter, picoammeter, or electrometer. Another important selection consideration is an instrument’s ability to adapt to new test requirements, which can help prevent premature obsolescence.

Figure 1. Source Measure Unit (SMU) instruments integrate the capabilities of a precision power supply with those of a high-performance DMM in a single instrument. SMU instruments can simultaneously source or sink voltage while measuring current, and source or sink current while measuring voltage. They can be used as stand-alone constant voltage or constant current sources, as stand-alone voltmeters, ammeters, and ohmmeters, and as precision electronic loads. Their high performance architecture also allows using them as pulse generators, as waveform generators, and as automated currentvoltage (I-V) characterization systems.

TECH ARTICLE Will this piece of equipment help me work more productively?

Every piece of hardware and software on the bench can make a substantial impact on your productivity. Does it offer the right interfaces to allow easy integration into a benchtop system with other hardware on the bench? Does it make it simple to store data and retrieve it when needed? Is operation intuitive, or will you constantly need to pull out the manual to use it?

What levels of resolution and accuracy are appropriate for my applications?

If your application requires a critical degree of resolution, accuracy, and even sensitivity, then certainly allocate your budget to get the right tools. But most applications don’t require extremes of either resolution or accuracy and spending money to achieve them simply makes it more difficult to afford essential equipment.

Keithley 2450 Advanced Touchscreen SourceMeter

What kinds of accessories or software do I need to complete my test setup?

Instrumentation is typically only one part of the total test solution; leave some room in the budget for accessories like safety test leads, probes, interfaces, switch hardware, text fixtures, and programming environments.

What can I afford to give up without compromising what I need to do?

A good rule of thumb is to spend the bulk of your budget on the capabilities that are the most critical to the work; pull hardware from the equipment pool or find a less expensive solution for the rest. For example, if the work demands the extended sensitivity only a nanovoltmeter or picoammeter can provide, consider economizing with a less costly DMM.

Can I count on the manufacturer to back up its equipment?

You need to factor the reputation of the manufacturer into the decisionmaking process right along with the price. Will you be able to obtain customer support, repairs, calibration a few years down the road? The initial purchase price is only a part of the total cost of ownership. Extended warranties and calibration contracts can reduce longterm maintenance costs while ensuring ongoing performance.

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Modern Test & Measure

The Realities of Oscilloscope Probes

By David Maliniak Technical Marketing Communication Specialist Teledyne LeCroy

Looking for a good, albeit very expensive, paperweight? Try using an oscilloscope without probes! Probes are often taken for granted, but they are one of the most critical elements of the signal chain in any test scenario.

Ideally, an oscilloscope probe would make contact with the circuit under test and transmit its signal from the tip of the probe to the instrument’s input with perfect fidelity.

We would like to see the probe exhibit zero attenuation, infinite bandwidth, and linear phase characteristics at all frequencies.

The circuit under test has its particular electrical characteristics for a given signal, which are what we want to measure. Alas, the probe itself is a circuit with its own electrical characteristics.

When the probe tip meets the circuit under test, their characteristics combine in a way that can affect the measurement results. The probe’s input impedance will be introduced into the circuit. All probes present some amount of resistive, capacitive, and inductive loading that must be accounted for.

8

Figure 1: Teledyne LeCroy's ZS2500 high-impedance active probe

TECH ARTICLE

For one thing, the probe’s lead length will present some amount of inductive loading to the input ground leads, as shown in an equivalent circuit diagram of a probe input (Figure 2). The ground lead is the primary return path for current that results from the input voltage acting with the probe’s input impedance. The ground lead and input lead’s inductances combine with the probe’s input capacitance to form a series LC network. That network’s impedance drops substantially at its resonant frequency, and this effect, known as ground lead corruption, is the cause of ringing often seen after the leading edge of pulses.

How can ground lead corruption be alleviated?

One way is to raise the resonant frequency of the LC network by decreasing the inductance, the capacitance, or both. Realistically, because the input capacitance is already very low, the only option is to reduce the input inductance. This is achieved by using input and ground leads that are as short as possible.

Capacitive loading can be a difficult nut to crack, as it can affect rise-time, bandwidth, and delay measurements. At high frequencies, capacitive loading can affect the amplitude and waveshape of measured signals.

Input inductance Input capacitance

Input

Circuit ground

Input resistance Ground lead inductance

Figure 2: Probe input equivalent circuit

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Modern Test & Measure

New VNA Series Delivers

VALUE and PERFORMANCE in Passive Device Testing Applications

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COVER INTERVIEW

Interview with

Aart Konynenberg Manager, Emerging Business Unit Anritsu

Anritsu

produces advanced test and measurement instruments for communications devices.

Their products are used in design, manufacturing, and maintenance of wired or wireless solutions, radio frequency and microwave solutions and optical solutions, among other data communications applications. Currently, their vector network analyzers (VNA) are attracting attention as low-cost, high-performance solutions for manufacturing applications.

EEWeb spoke with Aart Konynenberg, manager of emerging business at Anritsu, about how his company’s new line of instruments is meeting the need for economical VNAs used with manufacturing applications where cost-of-test is a primary issue.

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Modern Test & Measure Can you tell us about Anritsu’s history in the VNA market?

Why is there a need for economical VNAs at this time?

Anritsu Company’s Microwave Measurement Division (MMD) has been involved in the VNA market since the 1960s. In fact, Wiltron Company—the predecessor to Anritsu MMD—introduced the first true VNA, the swept-frequency model 310, in 1965. A few years later, the VNA was revolutionized with the introduction of the Wiltron 360.

Throughout the years, Anritsu MMD has continued to raise the bar when it comes to VNA technology. A recent example occurred in 2012, when the second-generation VectorStar™ family was introduced. Taking advantage of the engineering expertise that can only come from five decades of experience, Anritsu changed the way VNAs were viewed by removing the conventional limitations engineers had long accepted.

Downward pressure on pricing of consumer electronics such as smart mobile phones is driving the demand for low-cost instrumentation. Mobile phones contain many RF devices that are manufactured and tested to the OEM specification at the lowest possible cost.

Manufacturers track the cost by using the metric test cost per device. The price of the test instrument is a significant component of this metric.

How did you leverage that experience into developing the new ShockLine economical VNAs? “ShockLine VNAs are an ideal solution for manufacturing applications where cost-of-test is the primary issue.”

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ShockLine VNAs leverage Anritsu’s expertise in two well-known areas: low-cost, high-performance, small form-factor RF designs, and frequency scalable non-linear Transmission Line (NLTL) technology. In the past, these two areas of expertise resided in two different product lines. The ShockLine VNAs mark the intersection of these two technologies to bring a new level of price-performance to passive device test environments.

In addition, many applications require just simple S-parameter measurements.

Therefore, customers object to paying for unused features and functionality of current VNAs that have become highly complex and are tedious to operate.

ShockLine VNAs fill a current void in the market by addressing both these market considerations.

How does the new ShockLine VNA family fit into Anritsu’s overall product portfolio and philosophy?

The ShockLine family is an extension of the Anritsu VNA product line that also consists of VectorStar and the VNA Master™ hand-held analyzer series.

The addition of the ShockLine family gives customers greater flexibility when choosing an appropriate solution for their application at various performanceprice points. The VectorStar targets high-performance applications while VNA Master is the VNA of choice for field applications. ShockLine VNAs are an ideal solution for manufacturing applications where cost-of-test is the primary issue.

COVER INTERVIEW Please explain how Anritsu engineers globally collaborate when developing products in general and specifically in designing the ShockLine product family.

NLTL, commonly referred to as shock line technology, forms the basis for the Anritsu high-frequency ShockLine VNAs. The NLTL technology simplifies the internal VNA architecture and reduces the cost while enhancing accuracy and measurement repeatability at high frequencies. Our patented ShockLine technology is a global collaboration, as it was designed and developed in Morgan Hill, CA and manufactured in the Anritsu fabrication facility in Atsugi, Japan.

What market trends are addressed with the ShockLine VNA family?

Wide dynamic range, fast sweep speeds, and full S-parameter and timedomain measurement capabilities make ShockLine VNAs compelling matches for a broad range of customers. They are ideal for testing passive devices such as cables, connectors, filters, and antennas.

Mobile devices, M2M, system integration and core general purpose applications are market segments in need of the priceperformance offered by this VNA family as well.

“The NLTL technology simplifies the internal VNA architecture and reduces the cost while enhancing accuracy and measurement repeatability at high frequencies.”

What are your biggest challenges when addressing the market and how does Anritsu keep pace with the test needs of its customers?

The dynamic nature of the market has opened endless opportunities for Anritsu.

The trick is to focus on opportunities that fit best with the core competencies of the company and where Anritsu can deliver the best value to the customer.

The aforementioned target applications lie in some of the highest growth segments of the economy today. Anritsu keeps pace with technology by working directly with select customers who are market leaders in these particular segments. These relationships help us design test solutions that help engineers do their jobs more effectively and efficiently while improving time to market and lowering cost of test.

“Wide dynamic range, fast sweep speeds, and full S-parameter and time-domain measurement capabilities make ShockLine VNAs compelling matches for a broad range of customers.”

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Modern Test & Measure

Anritsu Introduces the ShockLine™ VNA Family

“Consisting of three instrument series, ShockLine brings unprecedented levels of price-performance, resulting in two key advantages—lower cost-ofownership and improved throughput.“

Vector network analyzers (VNAS) have been used for passive device testing for years. Many applications have required high-priced, high-performance, and full-featured VNA solutions. However, there are numerous environments that need simple S-parameter and time domain measurements at the lowest possible cost. Unfortunately, engineers have had to use high-end VNAs in these situations, adding unnecessary complexity and expense.

To address these applications, Anritsu has introduced the ShockLine™ VNA family. Consisting of three instrument series, ShockLine brings unprecedented levels of price-performance, resulting in two key advantages—lower cost-ofownership and improved throughput.

Anritsu ShockLine achieves the required measurement capability at the desired price point by incorporating four key design traits: Patented VNA On-A-Chip Architecture – This proprietary design is the foundation of the low-cost microwave and mm-wave frequency instruments.

Measurement Capability – Unlike other VNAs that have unnecessary complex features and functionality, the

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ShockLine VNAs offer simplicity in the form of single-ended and mixed-mode S-parameter measurement capability, including time domain characterization of passive devices.

Small Size – Designed exclusively for passive device test environments, the ShockLine family has a 2U high chassis with no display or keypad, making it easy for the VNA to be integrated into most conventional rack configurations.

Common GUI and SCPI Interface – All ShockLine VNAs have the same intuitive graphical user interface (GUI) and remote-programming interface, which reduces switching costs compared to other models.

COVER INTERVIEW

Anritsu developed three models that satisfy specific passive device test requirements: MS46524A 4-Port VNA Series – Engineers can conduct key tests, including 16 single-ended and mixedmode S-parameter measurements, with the ShockLine MS46524A VNAs. Additionally, time domain measurements are available as an option. Two models– one which covers the 10MHz to 4.5GHz frequency range and a second instrument that extends frequency coverage to 7GHz–are available. The VNAs can test multiband mobile handset components, such as switches and differential SAW filters; verify the performance of RF passive multi-port components, including antennas, duplexers, couplers, isolators, and circulators; and identify signal integrity issues on high-speed digital circuits.

MS46522A 2-Port RF VNA Series – Two models are featured in the ShockLine MS46522A family. One VNA has frequency coverage from 50kHz to 4.5GHz, while the other extends the frequency range to 8.5GHz. A 70 us/

point sweep speed, as well as >110 dB dynamic range and corrected directivity of >42 dB make it ideal for simple and cost-sensitive engineering and educational applications. In addition to full S-parameter measurements, the ShockLine MS46522A VNAs can conduct path-loss characterization of complex systems. Faults in broadband devices can be easily and quickly identified using a time domain with time gating option.

MS46322A 2-Port VNAs – Each VNA in the series features wide dynamic range, fast sweep speed, and full S-parameter and time-domain measurement capability. All six models have low-end frequency of 1MHz with high-end frequencies available at 4/8/14/20/30/40GHz so they can fit into numerous engineering, manufacturing, and university testing environments. The VNAs feature 220 us/pt. sweep speed, >100 dB dynamic range to 40GHz and wide IF bandwidth for fast test times and maximum throughput. With a corrected directivity of >/=42 dB, the Economy ShockLine MS46322A gives users reduced measurement uncertainty and small guard bands.

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TECH ARTICLE

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Modern Test & Measure

By Brig Asay Product Manager High Performance Oscilloscopes Agilent Technologies

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TECH ARTICLE

New Oscilloscope USER INTERFACES

Aim to Make Engineering Easier

O

ne of the last features for oscilloscope vendors to address on their oscilloscopes is their user interfaces. Until nearly 2010, most of the oscilloscope vendors employed user interfaces that were originally designed in the late 1900s. The first Windows-based oscilloscopes were introduced in 1997, and the user interfaces haven’t been overhauled since that time. While they were more modern than the old analog-display oscilloscopes, the user interfaces of the scope companies left quite a bit to be desired.

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Modern Test & Measure

T

he new user interface revolution began in 2008 when LeCroy introduced their 7Zi oscilloscope with a new user interface. For LeCroy, their user interface has been a strength since this introduction. Rohde and Schwartz introduced an oscilloscope shortly thereafter, which boasted of a new, better user interface. Finally in 2014, Agilent has overhauled their user interface and Tektronix promises that a new user interface is coming in the future. Why have the vendors all of the sudden begun to care about the user interface? The answer is very simple, the better the user interface, the better the data can be displayed, and the easier it is to analyze very complex data. Easier analysis of complex data, makes it possible for engineers and designers to get their jobs done faster.

“The better the user interface, the better the data can be displayed, and the easier it is to analyze very complex data.�

Figure 1.

New oscilloscope user interfaces provide complex analysis that was previously only done on a PC.

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Improvements in Data Display While a new user interface is good, oscilloscope users still want the best signal integrity, and so maximizing the signal to noise ratio of their measurement is always of utmost importance.

As measurements and displayed data continue to become more complicated it has become increasingly important to avoid overlaying the data (see figure 1). With only one display, this means minimizing the signals to see more data on screen (see figure 2). Oscilloscope vendors have solved this problem with grids inside of their displays.

LeCroy was the first oscilloscope vendor to provide sixteen grids, which each provided their own signal-to-noise ratio. Agilent has now answered this with sixteen grids of its own. With sixteen grids, individual data can be displayed vertically or horizontally without having to sacrifice signal to noise ratio. More importantly it gives users more flexibility in how data is seen (see figure 3).

TECH ARTICLE

Figure 2.

Overlaying waveforms to maximize SNR results in further complicating already complicated problems.

Figure 3.

16 grids makes it possible to analyze very complex signals.

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Modern Test & Measure

As a natural extension of having sixteen grids, users demanded to display measurement data across multiple monitors and see different data on the second monitor than what they see on their oscilloscope display. Again with its overhauled user interface LeCroy was the first to give the user the ability to choose which grid would be displayed in the additional monitor or the oscilloscope display.

Finally, users could take advantage of the flexibility in data display provided by Microsoft Windows. By displaying data on multiple displays, a user could really see data multiple signals and actually discern individual signals. LeCroy’s innovation was the first step in displaying data. Agilent has now improved this capability by providing “waveform areas.”

Waveform areas are essentially the data display of its previous user interface, but now Agilent oscilloscope users have eight waveform areas (see figure 4).

Each waveform has up to sixteen grids of data. This means that conceivably a user could see 128 grids of data with the new Agilent user interface. Waveform areas are also completely flexible. Each waveform area can be adjusted to the size that the user chooses (previously the grids and displays were always fixed to the size of the monitor or display). By using waveform areas, users can now see very complex data in the way that they want to see it. In the near future, expect that other vendors will follow the waveform area model provided by Agilent, giving oscilloscope users much more flexibility in their displayed data.

Math Capability As visualization improves, the ability to analyze more data transforms from a luxury to a must

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for engineers. One of the key tools for engineers is functions, which are tools that do math live on waveforms. Functions can be as simple as inverting the waveform and as complex as fast Fourier transforms (FFTs) with live views of peaks and spectral power. Previously scope companies would provide a maximum of four functions with limited capability. Tektronix was the first company to really innovate on the math function front.

Tektronix provided equation editor, which will apply any math equation on any waveform, where the equation can be as complicated as needed. Equation editor provided much more flexibility to users as it allowed them to work complicated functions while maximizing the use of four functions.

LeCroy and Agilent have both countered with the ability to do sixteen functions. With the ability to do sixteen functions, both scope companies allow for users to apply math such as a function on a function on a function, and so on. For instance a user could invert a waveform, then magnify it, then add it to another waveform, then differentiate it, and finally run an FFT on it. Each function can then be displayed in its own individual grid and, in the case of Agilent, can be undocked and moved to an entirely separate display. The advantage of using multiple functions is that engineers can now make multiple measurements on each function. Also having sixteen functions means that engineers can easily make multiple different functions based off a first function. Equation editor is unable to do this, which is the reason that LeCroy and Agilent chose this route (see figure 5).

TECH ARTICLE Figure 4.

Waveform areas provide full screen displays of data; each can have up to 16 grids.

Figure 5.

With up to 16 functions, real-time oscilloscopes make it possible to analyze very complex data.

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Modern Test & Measure

Real-Time Eye Analysis

Other Capabilities

A crucial measurement of waveform goodness is the real-time eye. To look at real-time eyes, all the vendors require additional software tools; however, most come equipped as “Digital Signal Analyzers� which have real-time eye analysis as a standard feature. By placing a waveform into real-time eye mode, oscilloscope users can see margins in their design. Real-time eye analysis has been limited to only looking at a single lane or a single real-time eye at once. Real-time eye analysis also was limited to essentially just making eye height and width measurements (see figure 6).

In addition to functions, waveform areas, and realtime eyes, oscilloscope companies have added much more analysis to their oscilloscopes. Users can now make up to 16 gated measurements (see figure 7).

Again the aforementioned limits have now changed with the new user interfaces. With its new user interface, Agilent will allow a user to look at a realtime eye of any signal of the oscilloscope (Agilent defines signals as channels, functions, equalized waveforms, etc.). Each real-time eye can have its own measurements and its own time base. Using the magnify function allows for users to look at multiple views of the same waveform. For instance, a user could look at both transition bits and nontransition bits at the same time. Users can then analyze and measure each of the individual eyes.

For an oscilloscope to view a real-time eye it must recover the clock of the signal. Real-time scopes use software clock recovery, allowing the other channels to be used for data. LeCroy recently introduced the ability to recover multiple clock-data rates and settings while analyzing multiple real-time eyes.

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A gated measurement is simply a selected portion of the waveform. The use of gates used to be a measurement only needed for disk-drive analysis, but has since grown to be widely used. For example, you can gate on a burst of data inside an entire acquisition and then recover the real-time eye of only the bursty data using a gated function For technologies such as double data rate (DDR), this opens up entirely new ways to look at data.

For RF measurements, with recent user interface improvements, oscilloscopes have added the ability to do amplitude modulation or envelope mode.

Engineers can create the envelope, measure it, smooth it out, and even run an FFT from the created envelope.

Oscilloscope will recover a clock for the data and can separate jitter into random and deterministic components. LeCroy has added the ability to do this on up to four lanes at once. All vendors will now equalize a signal and de-embed fixtures and cables. Recently Agilent even added the ability to characterize insertion loss of a fixture or channel in its repertoire.

TECH ARTICLE Figure 6.

Real-time eye display of the waveform.

Figure 7.

Measurement gates allow for users to look at multiple instances of a waveform simultaneously.

25

Modern Test & Measure

Conclusion With the introductions of new user interfaces, oscilloscope vendors have made it easier to analyze data, making engineers more productive. More advanced user interfaces make it possible to do less analysis on PCs and more analysis on the oscilloscope itself. However, oscilloscope vendors are also allowing their interfaces to run on a PC to free their oscilloscopes for other uses. Oscilloscope users need to take advantage of key features such as waveform areas, multiple functions, real-time eyes, and many other powerful features to maximize the oscilloscopes potential. Of course the one downside with all the slicing of data is that oscilloscopes must have a strong processor to handle the influx of data. Over the next several years, oscilloscope companies will continue to put more analysis on their instruments, and engineers will further benefit from these features.

“In the near future, expect that other vendors will follow the waveform area model provided by Agilent, giving oscilloscope users much more flexibility in their displayed data.”

26

Brig Asay Product Manager High Performance Oscilloscopes Oscilloscope Product Division Electronic Measurements Group Agilent Technologies Brig Asay manages product planning and strategic marketing for Agilent’s high performance oscilloscope business.

Brig joined Agilent Technologies in 2005 as a Technical Support Engineer. During his time with Agilent, he has held the following positions: • Marketing Operations Manager; he oversaw the marketing budget and managed the technical support and learning products teams.

• Technical Support Engineer; he helped solve numerous customer problems.

Previous to Agilent, Brig worked at Micron Technologies, Inc. as a Test Engineer. Brig graduated with an MBA from Northwest Nazarene University and BS Electrical Engineering from the University of Wyoming. He is a published technical author.

TECH ARTICLE

27

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