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    MEMS Vibration Monitoring: From Acceleration to Velocity

    Transmit LO Leakage (LOL)—An Issue of Zero-IF That Isn’t Making People Laugh Out Loud

    Ultrawideband Digital Predistortion (DPD): The Rewards (Power and Performance) and Challenges of Implementation in Cable Distribution Systems

    Improved DAC Phase Noise Measurements Enable Ultralow Phase Noise DDS Applications

    Mirror, Mirror on the Wall—Understanding Image Rejection and Its Impact on Desired Signals

    Wireless Current Sense Circuit Floats with Sense Resistor

    GaN Breaks Barriers—RF Power Amplifiers Go Wide and High

    Intelligent Video Analytics at the Edge of IoT

    Uncompromising Linearity from the LTC2185 and ADA4927-1

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    51

    10 Massive MIMO and Beamforming: The Signal Processing Behind the 5G Buzzwords

    Volume 51, Number 3, 2017 Your Engineering Resource for Innovative Design

    http://www.analog.com/en/analog-dialogue.html http://www.analog.com/en/index.html http://www.analog.com/en/analog-dialogue.html

  • Analog Dialogue Volume 51 Number 32

    In This Issue

    MEMS Vibration Monitoring: From Acceleration to Velocity MEMS accelerometers have finally reached a point where they are able to measure vibration on a broad set of machine platforms. Recent advances in their capability, along with the many advantages that MEMS accelerometers already had over more traditional vibration sensors (size, weight, cost, shock immunity, ease of use), are motivating the use of MEMS accelerometers in an emerging class of condition-based monitoring (CBM) systems. As a result, many CBM system architects, developers, and even their customers are giving consideration to these types of sensors for the first time.

    5

    Massive MIMO and Beamforming: The Signal Processing Behind the 5G Buzzwords Our thirst for high speed mobile data is insatiable. As we saturate the available RF spectrum in dense urban environments, it’s becoming apparent that there’s a need to increase the efficiency of how we transmit and receive data from wireless base stations.

    Base stations consisting of large numbers of antennas that simultaneously communicate with multiple spatially separated user terminals over the same frequency resource and exploit multipath propagation are one option to achieve this efficiency saving. This technology is often referred to as massive MIMO (multiple-input, multiple-output).

    10

    Orthogonal Perspectives I am using a MEMS inertial measurement unit (IMU) in a self-balancing guidance control system for a personal transportation platform. Can I expect a consumer targeted IMU to eliminate all misalignment errors between each sensor if all of the core sensor elements are on a single piece of silicon?

    15

    Transmit LO Leakage (LOL)—An Issue of Zero-IF That Isn’t Making People Laugh Out Loud Transmit LOL refers to transmit local oscillator leakage. If you are working with RF mixers and have not corrected transmit LOL, this article explains why LOL correction is so important, especially in zero-IF architecture.

    17

    Ultrawideband Digital Predistortion (DPD): The Rewards (Power and Performance) and Challenges of Implementation in Cable Distribu- tion Systems Digital predistortion (DPD) could enhance the efficiency of power amplifiers in our cable infrastructure and more. Time to improve efficiency for the next generation of cable technologies.

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  • Analog Dialogue Volume 51 Number 3 3

    Burned by Low Power? When Lower Current Consumption Can Get You Into Trouble What happens if you are replacing one part with a better (less power consuming) one and forget to check the power supply specifications? This RAQ comes out of a customer experience discussing some unexpected regulator phenomena.

    29

    Improved DAC Phase Noise Measurements Enable Ultralow Phase Noise DDS Applications How can a good high speed or radar system be improved further? Phase noise is one of the critical issues to take care of. Not surprisingly, surrounding components and test setup improvements could make the difference. Peter Delos and Jarrett Liner—system engineers of instrumentation, aerospace, and defense—discuss these topics.

    31

    Mirror, Mirror on the Wall—Understanding Image Rejection and Its Impact on Desired Signals Patrick Wiers introduces you to image rejection. Despite the title, it has nothing to do with what you see in a mirror. Images in the frequency domain should be rejected. The questions are: how to do that with a zero-IF approach? Without the possibility of active or passive filtering? And what is the right choice between the wideband and narrow-band transceivers offered?

    36

    Wireless Current Sense Circuit Floats with Sense Resistor In our premiere LTC article, Kris Lokere introduces a wireless current sense circuit that floats with sense resistors. An interesting concept—isolation without using traditional optocouplers or inductive or capacitive barriers? Curious? The secret is called SmartMesh® IP network. You will also see how well Analog Devices and Linear Technology’s products fit together in a combined solution.

    41

    Accelerometer Tilt Measure Over Temperature and in the Presence of Vibration As you know, we live on the Earth with 1 g acceleration toward the planet. An accelerometer with its sensing element oriented in this direction will measure 1 g. Tilt the sensor 90° and the output becomes 0 g. Everything between the tilt is related to the sine and cosine of the angle. But add in the factor of temperature and vibration, and are you still able to measure it with good enough accuracy? See what Christopher Murphy has to say.

    43

    GaN Breaks Barriers—RF Power Amplifiers Go Wide and High Keith Benson discusses new approaches with GaN in power amplifier designs. He looks at products that demonstrate the possibilities of GaN technology, including covering wide bandwidths and providing high power and efficiency.

    45

  • Analog Dialogue Volume 51 Number 34

    In This Issue

    Intelligent Video Analytics at the Edge of IoT Tyle Jesiel introduces us to SNAP sensors working in combination with our Blackfin® technology—a mix of logarithmic imaging and node analytics in the Internet of Things (IoT). By bringing in-depth video processing and analytics to the node, it will be possible to dramatically reduce the amount of data transmission into the cloud.

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    Uncompromising Linearity from the LTC2185 and ADA4927-1 I hope you had a chance to read our article from the August issue featuring products from Linear Technology and Analog Devices. We continue the series this month with the combination of a precision op amp with great linearity driving a precision 16-bit ADC, which compliments the linear requirements for excellent ac performance applications.

    51

    A Low Power, Low Cost, Differential Input to a Single-Ended Output Amplifier A low power, low cost, differential input to a single-ended output amplifier from Jordyn Rombola and Chan Trau is the topic of this RAQ. This article asks: How often do you need a ground referenced signal after a differential transmission of that signal? Using a differential to a single-ended application, the differential amplifier rejects the common-mode voltage and the remaining voltage is amplified and presented on the amplifier output as a single-ended voltage.

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    Analog Dialogue is a technical magazine created and published by Analog Devices. It provides in-depth design

    related information on products, applications, technology,

    software, and system solutions for analog, digital, and

    mixed-signal processing. Published continuously for

    50 years—starting in 1967—it is produced as a monthly

    online edition and as a printable quarterly journal featuring

    article collections. For history buffs, the Analog Dialogue archive includes all issues, starting with Volume 1, Number 1,

    and four special anniversary editions. To access articles,

    the archive, the journal, design resources, and to subscribe,

    visit the Analog Dialogue homepage, analogdialogue.com.

    Bernhard Siegel, Editor Bernhard became editor of Analog Dialogue in March 2017, when the preceding editor, Jim Surber, decided to retire. Bernhard has been with Analog Devices for over 25 years, starting at the ADI

    Munich office in Germany.

    Bernhard has worked in various engineering roles including sales, field applications, and product engineering, as well as in technical support and marketing roles.

    Residing near Munich, Germany, Bernhard enjoys spending time with his family and playing trombone and euphonium in both a brass band and a symphony orchestra.

    You can reach him at bernhard.siegel@analog.com.

    http://www.analog.com/en/analog-dialogue.html http://www.analog.com/en/analog-dialogue.html mailto:bernhard.siegel%40analog.com?subject=

  • Analog Dialogue Volume 51 Number 3 5

    MEMS Vibration Monitoring: From Acceleration to Velocity By Mark Looney

    Share on

    a(t) = APK × sin(ωv × t)

    Arms = APK √2

    fv = ωv 2�

    (1)

    In most CBM applications, the vibration on a machine platform is often going to have more complex spectral signature than the model in Equation 1, but this model provides a nice starting point in the discovery process, as it identifies two common vibration attributes that CBM systems often t

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