Electronics_For_You_August_2016

August 2016 ContentsINssexute• S••oSSlaotrrladCteeergilnlssicgtTaE/odtlieoeIncnsvtosreoldrnteeicrrissng VOL. 05 | nO. 04 issn-2454-4426Editor : ramesh Chopra Tech FOCus Buyers’ GuideEditorial : Editorial Secretary 22 does Your Car 70 Choosing The Have A driver’s Right Led COBCorrESpondEnCE phone: 011-26810601; E-mail: [email protected] Licence 136 Buyers’ Guide: Fast, Functional And (technical queries: [email protected]) Affordable TabletsSubSCriptionS & : phone: 011-26810601 or 02 or 03 18 Information TechnologymiSSing iSSuES E-mail: [email protected] 139 Do-It-Yourself: How To Protect Your Living With Quantum ComputingbaCk iSSuES, : kits‘n’Spares, new delhi Smartphone’s DatabookS, Cds, phone: 011-26371661, 26371662 28 Power SupplypCbs etc. E-mail: [email protected] Do-It-Yourself Net-Metering In India: Way To A SecurenEwSStand : ph: 011-40596600 Power FuturediStribution E-mail: [email protected] 32 HealthcareadvErtiSEmEntS Electric Brain Stimulation Needs CautionnEw dElhi : ph: 011-26810601 or 02 or 03 38 Satcom(hEad offiCE) E-mail: [email protected] IRNSS: India’s Attempt At Gainingmumbai : ph: 022-24950047, 24928520 Independence From GPS E-mail: [email protected] 44 ManufacturebEngaluru : ph: 080-25260394, 25260023 86 Electronics DIY Tools For Hobbyists And Professionals E-mail: [email protected] Electromagnetic Compatibility: Multi-Layer 90 7×5 LED Matrix Using Arduino PCB Designing (Part 2 of 5) 94 Arduino Based RGB Colour Code GeneratorpunE : ph: 08800295610, 09870682995 96 Home Automation Using Android E-mail: [email protected] 54 Defence Electronics 98 Webcam View Illuminator 100 Low-Cost Quadraphonic Amplifiergujarat: : ph: 079-61344948 Directed Energy Weapons: Less-Lethal Laser 103 Temperature Based Fan Speed Control And E-mail: [email protected] Weapons (Part 5 of 8) Monitoring Using ArduinoChina : power pioneer group inc. 62 Embedded 105 Portable Crystal Tester ph: (86 755) 83729797, (86) 13923802595 106 Arduino Based Programmable Digital Data Display E-mail: [email protected] MCUs And PSoCs In Electronic Toy Applications 108 Raspberry Pi As World Webcam Server 110 Creating Game Using Python Within Ten Minutesjapan : tandem inc., ph: 81-3-3541-4166 76 Test & Measurement E-mail: [email protected] EFY Plus DVD Generating Functions For A Diverse RangeSingaporE : publicitas Singapore pte ltd Of Applications Jaamsim: Simulation Tool Simplifying Complex Systems ......I ph: +65-6836 2272 OpenModelica And The Wonderful World Of Simulation... IV E-mail: [email protected] 82 EFY Plus DVD Xcos: Simulate Hybrid Systems Easily ............................. VIItaiwan : j.k. media, ph: 886-2-87726780 ext. 10 Phenomenal Electronic Design Software To Regulars E-mail: [email protected] Impress The Engineer In You 06 FeedbackunitEd StatES : E & tech media 83 Innovation 08 Q&A ph: +1 860 536 6677 10 Useful Websites E-mail: [email protected] A Smart Packaging Platform For Safe, 12 Tech News Secure Delivery 116 Make in India: Industry Newsprinted, published and owned by ramesh Chopra. printed at international 128 New Productsprint-o-pack ltd, C-4 to C-11, hosiery Complex, phase-ii Extension, noida-201305, 120 Make In India 134 First Lookgautam budh nagar, uttar pradesh, on the first day of each month and published 141 Business Pages Adsfrom d-87/1, okhla industrial area, phase-1, new delhi 110020. Copyright 2016. Market Survey: Catching The Pulse Of 157 Electronics Mart Adsall rights reserved throughout the world. reproduction of any material from The LED Lighting Market 160 Product Categories Index + Attractions During 2016this magazine in any manner without the written permission of the publisher is 161 Advertisers’ Indexprohibited. although every effort is made to ensure accuracy, no responsibility eStylewhatsoever is taken for any loss due to publishing errors. articles that cannot 131 Communication: Today’s Concepts,be used are returned to the authors if accompanied by a self-addressed andsufficiently stamped envelope. but no responsibility is taken for any loss or delay in Tomorrow’s Phonesreturning the material. EfY will not be responsible for any wrong claims made byan advertiser. disputes, if any, will be settled in a new delhi court only. InterviewsSUBSCRIPTION RATES 79 THe inTeRneT OF THinGs: 80 dATA AnALYTiCs: “Let us face it, no one likes cabling” “Trucks use data to figure out how toPeriod Newstand Price You Pay Digital Overseas — shakti Leekha, senior general manager and apply brakes” — Richard Rovner, vice presidentYear (`) (`) (`) Digital Print head - iBMs, Bajaj electricals Ltd - marketing, MathWorks uS$ 15 —two 2400 1800 750 uS$ 5 uS$ 120one 1200 960 280please send payments only in favour of EFY Enterprises Pvt Ltd4 August 2016 | ElEctronics For You plus www.EFYmAg.com



Feedback Your suggestionsThanks! Corrections Please tell me the procedure for its submission.I am an Indian citizen from In ‘Things You Want to Know’ QA section ofKozhikode presently working as June issue, under Table II, PWM pins of Uno Aanchal Katyaa lecturer in electronics and com- board have been mentioned as 16 instead Through emailmunications at Leibniz Universität, of 6.Hannover, Germany. For the last 35 EFY. You may forward your contribu-years I have been a regular reader Tejeet Magar tion to our editorial secretary on edit-of several electronics magazines [email protected] as per guidelines availablepublished worldwide. But EFY has In ‘Programmable Power Supply With at http://efymag.com/Guidelines_for_admittedly remained close to my TL431’ DIY article published in June issue, EFY_authors.docheart during all these years for two R8 resistor is mentioned as 0.33E, 3Wmain reasons. It comes with the resistor in circuit as well as in parts list. But Weighing sCale ProjeCTfragrance of the land of my country it is wrongly shown as 0.33E, 2W resistor inand every issue comes with content- the PCB layout. Please publish the circuit diagram forrich information on almost every a digital weighing scale.diversified field of latest electron- Arunjo Maliekkalics developments that keep me up Hitesh Nirdoshto date. My sincere thanks to your In ‘LME49710 Based Audio Amplifier’ DIY Through emaileditorial team for all the appreciable article published in June issue, secondarywork they are carrying out. voltage of X1 is wrongly mentioned as 12V EFY. We will try to publish the AC near BR1 in the schematic diagram and mentioned DIY article in one of our I especially like articles on VLSI, component layout instead of 15V AC as forthcoming issues.FPGAs and DIY projects on Raspberry mentioned in the parts list.Pi and Python. The eclectic score of arduino for aTmega32writeups in these articles have been  In ‘Wireless Baby Monitor’ DIY articleadmired by the students of Asian published in June issue, value of inductor In ‘Arduino For ATmega32’ DIY projectorigin here in Hannover. This is my L1 is wrongly mentioned as 1-micro Henry published in June issue, the prototypethird letter to EFY editor, and is espe- in the third column, instead of 0.1-micro image shows FT232. The design shouldcially to salute the work of EFY team. Henry. include FT232 USB-to-TTL converter.Michael Tooley  In ‘Programmable Power Supply With A. AbhayThrough email TL431’ DIY article published in June is- Through email sue, value of capacitor C9 was wronglysolar Charge mentioned as 47µF instead of 100µF in the EFY. USB-to-TTL converter is not partConTroller component layout on page 94. of the project.I am a regular reader of EFY. The DIY  In ‘GSM Based Messaging Using Arduino’ image ProCessingsection is very useful for engineer- DIY article published in June issue, digitaling students. I am working on solar pin 5 of Arduino was wrongly connected to Source code of ‘Image Processingprojects, so would like to know about D3 pin of LCD1 in the component and PCB Using MATLAB’ DIY article publishedthe solar charge controller. Please let layouts. It should be connected to D4 pin in July issue is not available on www.me know of any websites or circuits of LCD1. efymag.com/sourceissue.asp?id=12.published in EFY for reference. Could you please provide me with the A. Samiuddhin correct link?Vignesh VickyThrough email article on http://electronicsforu.com/ Sundar B. electronics-projects/photovoltaic-bat- Through emailEFY. Thanks for the feedback and tery-charge-controllerrequest! ‘Photovoltaic Battery Charge EFY. Thanks for pointing out theController’ DIY project was published arTiCles for efY mistake! We have uploaded thein EFY. You can find the complete source code. I would like to send my project 6 August 2016 | ElEctronics For You based on MSP430G2553 on En- ergia platform, which is a 16-bit programming logic and low-power- consumption microcontroller. www.EFYmAg.com



Q&A Things You WanTed To KnoW!Ques. What is the differ- Application. High-power LEDs are implemented and tested with the helpence betWeen high-poWer used for LED ceiling lights, LED bulbs, of hardware description language andLeds and LoW-poWer Leds? LED streetlights and so on. Whereas, its tools. low-power LEDs are used for LEDpamarthi Kanakaraja panel lights, LED downlights, LED RTL coding. RTL is an acronym tubelights, LED strips and so on. for register-transfer level. It meansans. The differences are as follows: VHDL/Verilog code written based on Q2. What is VLsi design the architecture, how data is trans- Light output. The most important fLoW, Y-chart and design formed and how it is passed fromdifference between low- and high- hierarchY in VLsi sYstems? register to register.power LEDs is the amount of lighteach puts out. Low-power ones emit sachin soni RTL verification. In VLSI design,a few lumens at most—usually in RTL simulation and verification is ansingle figures—although newer white a2. The VLSI design process at various important step, which ensures thator blue ones can be slightly brighter. your design is logically correct andA typical 3W high-power LED, on the levels is usually evolutionary in nature. without timing errors. Various simula-other hand, has a light flux of over 150 First, the initial design is prepared and tion tools like ModelSim or synopsyslumens and some very high-end ones tested against all requirements. tools can be used for verification.can exceed 1000 lumens. Y-chart, first introduced by D. Ga- Synthesis. At this stage the design Heat sensitivity. Heat sensitiv- jski, represents a complete VLSI design gets physical, which means that RTLity is not a problem with low-power flow used for most logic chips using is converted into some design inLEDs, but modern high-power ones design activities on three different axes terms of logic gates, which drive theuse a much higher current. Hundreds that resemble the letter Y. circuit and architecture.of milliamps is normal; some go over1A. Even with their high efficiency, a Y-chart mainly consists of three Back-end. After synthesis, thelot more heat is produced, and unless domains: behavioural, structural and final design is handed over to the ICproperly managed, it is likely that the geometrical layout. Each domain can be manufacturer.LEDs could fail pretty quickly—usually divided into levels of abstraction, usingwithin seconds. concentric rings. At the top level (outer Tape-out and foundry. This step ring), we consider the architecture of is part of the backend where the final High-power LEDs will always be the chip, and at lower levels (inner result of first five steps, that is fron-mounted on some kind of heat-sink for rings) we refine the design into detailed tend, is provided to the manufacturerthis reason. Often it is simply the cas- implementation. in the form of a photomask. Then, theing of the device these are in, like the manufacturer performs wafer process-body of a flashlight. LED light bulbs In VLSI design flow, various ab- ing, testing, packaging, etc to test theusually have a large heat-sink built into stractions of design are behavioural, physical IC. Finally, when all require-the base. logic, circuit and mask layout. Here, ments are met, the design is sent for verification of the design plays a very mass production. Power consumption. A 1W to 3W important role in every step during theLED is usually used for high-power LED design process as given below. The design hierarchy in VLSI islights. Low-power LED lights adopt based on divide-and-conquer tech-SMD LEDs, which mainly include SMD System specification. Specifica- nique. In this, the task is divided5050 0.2W each, SMD 3258 0.06W tions always come first. At this stage, into smaller tasks so that the designeach, SMD 3014 0.01W each, SMD 5630, designing specifications as per the reaches the simplest level and manu-0.5W each and SMD 5730 0.5W each. market requirement is done; these facturing becomes easier. You may describe the functionality, interface refer following link for details: Cost. The cost of high-power LEDs and architecture of the digital IC to www.tutorialspoint.com/vlsi_design_is higher than of low-power LEDs. First, be designed. digital_system.htmthe cost itself is high. Second, high-power LEDs require an aluminium heat- Architecture. With the help of Answers compiled by EFY senior application engineer,sink, while low-power ones only need the specification sheet, the target IC’s Nidhi Kathuria. Letters and questions for publicationan ordinary circuit board. Low-power architecture is decided and a layout for may be addressed to Editor, Electronics For You,LED could also dissipate heat naturally. the same is designed using EDA tools. D-87/1, Okhla Industrial Area, Phase 1, New Delhi In the next step, this architecture is 110020 (e-mail: [email protected]) and should include name and address of the sender8 August 2016 | ElEctronics For You www.EFYmAg.com



UsefUl Websites ElEctronic dEsign automationDesigning PCBs and ICs has always been challenging. To make the task easier, electronic design automation (EDA) tools are used. This month we have for you resources that will help you make the most of EDA tools Compiled by nira j sahay nptel.ac.in kicad-pcb.org edaplayground.comNational Programme on Technology KiCad is an open source EDA Playground gives Enhanced Learning (NPTEL), a software suite for EDA. The engineers immediate hands-on programs handle schematic exposure on how to simulateproject funded by Ministry of Human capture and PCB layout with SystemVerilog, Verilog, VHDL, Resource Development (MHRD), C++/SystemC and other HDLs. Gerber output. The suite All you need is a Web browser. was first conceived in 1999 to pave runs on Windows, Linux and the way for introducing multimedia OS X, and is licensed under The goal is to accelerate the and Web technologies to enhance learning of design/testbench GNU GPL v3. The website development with easier code- the learning of basic science and has tutorials and software sharing and simpler access to engineering concepts. The website for different platforms for EDA tools and libraries. On the has a few good tutorials on EDA. downloading. It also has site you can share your code forums that are run by KiCad and simulation results with ahttp://nptel.ac.in/course.php?disciplineId=106 users for the general KiCad Web link. It is perfect for Web community to ask questions forum discussions or emails and EDaCafe.com is great for asking questions or and help each other. EDACafe.com serves the sharing knowledge. informational and business-to- http://kicad-pcb.org business needs of the professional www.edaplayground.com/home electronic design community. The geda-project.org site’s target audience is system This is the home for gEDA project, designers and managers. You can www.geda-project.org which was started because of find everything related to EDA, be the lack of free EDA tools for POSIX systems, with the primary it NEWS or details of events purpose of advancing the state or tutorials here. of free hardware or open source hardware. gEDA project is www10.edacafe.com/resource/ developing a full GPL’d suite and Resource-Categories-EDA-Tutorials/10046/ toolkit of EDA tools. It also offers all packages for download that are category.html needed to install and run gEDA on different platforms. 10 August 2016 | ElEctronics For You www.EFYmAg.com



Tech News Technology UpdaTesWorld’s first 1000-core processorThe microchip with 1000-processor cores is thought to be the fastest designed in a Scientists have unveiled the world’s firstuniversity lab (Image courtesy: www.ucdavis.edu) 1000-processor microchip, called KiloCore, which is capable of working through 1.78 trillion instructions every second. Each of those 1000 processors can run independent- ly, which makes the chip suited to intensive tasks like encryption and weather forecast- ing. With some low-energy engineering, it can be powered by only one AA battery. Because each processor can turn on and shut down independently of the others, it is about 100 times more efficient at executing instructions than today’s laptops, according to the researchers who developed it at University of California, Davis, USA, and IBM. Today’s top-end smartphones have quad- or octa-core processors in them, so this is more than a 100-fold increase in terms of the number of cores. The more the cores, the more tasks you can get through simultaneously. While that does not make much of a difference for things like Facebook or Spotify, it can significantly boost supercomputer-level processing.World’s fastest supercomputer is made in ChinaSunway TaihuLight, the world’s fastest supercomputer, At its peak, the supercomputer can perform around 93,000 trillion calculationsis entirely made in China and does not rely on American per second (Image courtesy: www.bbc.com)processors. Instead, it relies on the locally-made Shen-Wei processor and custom interconnect called SunwayNetwork. The supercomputer establishes Chinese domi-nance on supercomputing technology. Sunway TaihuLight is currently functional atNational Supercomputing Center at Wuxi nearShanghai, China. Its primary job is to help withtop-notch engineering and research in climate andweather-related calculations, advanced biological andgeological research and in manufacturing and BigData analytics. SW26010 is a 260-core microchip that cranks a littleover three teraflops. TaihuLight has one such processorin each of the 40,960 nodes, allowing the machine toreach 125-peak petaflops. Linpack mark leaves out acouple of petaflops to mark 93 petaflops performance.12 August 2016 | ElEctronics For You www.EFYmAg.com



Tech News China’s underwater great wall of robots China is designing a manned deep-sea space station to hunt for mineral resources in South China Sea, according to a Bloomberg report. The said underwater wall essentially14 August 2016 | ElEctronics For You A fleet of unmanned vehicles, namely sea drones, would be part of the underwater wall defence system (Image courtesy: www.seeker.com) refers to a network of floating and submerged sensors de- signed to detect enemy submarines, involving underwater robots and drones. The proposed location is significant because South China Sea is a highly-disputed area these days among China and its neighbours, especially Vietnam and The Philippines. The oceanic base would be built as deep as 3000 metres (9800-feet) below the surface, and would be inhabited by a full-time crew. Robots that can assemble telescopes in Space Scientists, including one of Indian origin, have designed an extremely large telescope that can be assembled by a robot in Space to help enhance the ability of astronomers to peer deep into the cosmos. Ground based telescopes are limited by atmospheric effects and by their fixed location on the Earth. Space based telescopes do not have those disadvantages but have other limits such as overall launch vehicle volume and mass capacity. Design of a modular Space telescope that overcomes restrictions on volume and mass may allow telescope components to be launched incrementally, enabling the design and deployment of extremely-large Space telescopes. The robotically-assembled modular Space telescope (RAMST), designed by Nicolas Lee and colleagues at California Institute of Technology, USA, and NASA’s Jet Propulsion Laboratory, USA, in the USA, focuses primarily on a robotic system that perform tasks in which astronaut fatigue would be a problem. www.EFYmAg.com

Robot that walks like a humanA bipedal robot can now walk using a heel-toe motion thatcopies human locomotion more closely than flat-footedrobot walkers can. By rocking its feet forward from theheel and pushing off at thetoe, DURUS robot imitates thewalking motion of people,making it more energy-efficientand better at navigating uneventerrain, according to ChristianHubicki, postdoctoral fellowin robotics at Georgia Instituteof Technology and one ofthe researchers who helpedDURUS walk.The humanoid robotDURUS was designedcollaboratively by theresearch non-profit SRIInternational and Georgia DURUS, the Robo-Walker (ImageTech’s Advanced Mechanical courtesy: www.news.gatech.edu)Bipedal Experimental Robotics(AMBER) Lab. An earlier DURUS design was modified toaccommodate the new manner of walking, enabled bya novel mathematical algorithm that adjusts the robot’smomentum and balance, one step at a time.Tiny camera that can be injectedinto the brainResearchers at University of Stuttgart, Germany, have devel-oped a tiny camera that could be used in medicine, securitymonitoring and for miniature robots. They have used 3D-printing methods to build the camera’s three lenses layer-by-layer. This technique represents a paradigm shift in theThe compound lens is just 100 micrometres (0.1 millimetres or 0.004 inches) ElEctronics For You | August 2016 15wide, and 120 micrometres with its casing (Image courtesy: www.phys.org)www.EFYmAg.com

Tech Newsmanufacture of small cameras, according to the reasearchers. Engineered sand to cool The result is a compound lens just 0.1-millimetre electronic deviceswide, which only took a few hours to design, manufacture A USA based researcher has devised a new type of sand thatand test. It can focus on images from a distance of three can provide improved cooling for power-hungry electronic de-millimetres, and relay these down the length of a 1.7-metre vices. Baratunde Cola, associate professor at Georgia Instituteoptical fibre that it is attached to. of Technology, USA, has devised silicon-dioxide nanoparticles coated with a high-dielectric-constant polymer that could be The whole system fits comfortably into the needle used potentially for heat dissipation from power electronics,of a standard syringe, allowing it to be injected into the LEDs and other applications with high heat fluxes.human body, or even the brain. From there it can act as anendoscope, giving doctors the ability to examine the inside According to the findings, the silicon-dioxide does notof the body directly. do the cooling itself and the unique surface properties of the coated nano-scale material conducts heat at potentiallyBacteria-powered batteries higher efficiency than existing heat-sink materials. Using thefor smartphones collective surface electromagnetic effect of the nanoparticles, thermal conductivity can increase 20-fold, allowing it toA team of scientists from Oxford University, UK, has shown dissipate heat much faster.how the natural movement of bacteria could be harnessed toassemble and power microscopic windfarms or other man- The researchers have used ethylene glycol, a fluidmade micromachines such as smartphone components. commonly used in vehicle antifreeze, as a heat-dissipation material that, at the same time, does not conduct electricity. The study used computer simulations to demonstratethat the chaotic swarming effect of dense active matter Humans, robots work in harmonysuch as bacteria can be organised to turn cylindrical rotors at Ford Cologne factoryand provide a steady power source. Most factory robots do not have the ability to stop or subtly These biologically-driven power plants could someday adjust their motion, so anyone who gets in the way is atbecome microscopic engines for tiny, man-made devices risk of injury. Ford has found a way around this problem,that are self-assembled and self-powered—everything from and is putting humans side-by-side with robots in its Co-optical switches to smartphone microphones. logne factory to validate its approach.Octopus-like smart adhesive sensors Ford assembly-line staff in Europe is working hand-in-hand with collaborative robots, known as co-bots, to fit shock absorbers to Fiesta carsA team of researchers from South Korea has developed a (Image courtesy: https://media.ford.com)flexible-pressure sensor by mimicking the suction cups on an Ford’s new robots are being used to fit shock absorbers to Fiestas. Rather than forcing an assembly-line workeroctopus’s tentacles. Researchers from Ulsan National Institute to manipulate a heavy shock absorber above their head, workers can use the robots to lift and position the part, of Science And before finishing the operation with the push of a button. The robots have been programmed to be conservative when Technology (UNIST) it comes to human contact. If an arm or finger gets in the way, sensors detect the obstruction and the machine stops and Korea Insti- moving to protect the worker. tute of Science and Technology (KIST) studied the adhesive mechanism of octo- pus suckers and used it to develop a new type of suction basedThe scientists hope that their product can adhesive material.be used as the substrate for wearable By mimickinghealth sensors or band aids that stick tothe skin at normal body temperatures muscle actuationbut fall off when rinsed under cold water to control cavity-(Image courtesy: www.vishwagujarat.com) pressure-induced adhesion of octopussuckers, Hyunhyub Ko from UNIST has used a uniquerubbery material to create an array of micro-scale suckers,which include pores that are coated with a thermally-responsive polymer to create sucker-like walls.16 August 2016 | ElEctronics For You www.EFYmAg.com



information technologyLiving With Quantum Computing Kanchan Verma Importance of computers in the present • Left to run long enough, the societies is M.Tech from day is well known to all. These ma- within the simulations would eventually Department of chines have almost taken over man- be able to create their own simulations, Computer Science power and mostly for the betterment (with also indistinguishable from reality to the and Engineering the exception of creating unemployment). sub-simulations inhabitants. PIT, Kapurthala (PTU Still, people expect computers to be more Certain tasks, which have long been campus), Jalandhar, useful and powerful in times to come, and Punjab different computing technologies of the thought impossible (or intractable) for clas-Known as D-Wave, future are always on constant watch. sical computers, will be achieved quicklyGoogle’s quantum and efficiently by quantum computers.computer is making the The future of computing and the new These computers will be millions of timesleap from 512 qubits fields of computer sciences paving the way more powerful than conventional comput-to more than a 1000 for the next digital revolution are com- ers, and quantum computing could lead toqubits—a leap that does mon topics of discussion. In this direc- huge improvements in machine learning,not require a significant tion, quantum computing technologies artificial intelligence, computer simulationsincrease in power and their emergence in the near future and cryptography. All of this could funda- are discussed. It is expected that quantum mentally alter the way our society operates. computing technologies will reach the masses by 2020. This article presents how Quantum computers will be able to quantum computing will change lives, outperform conventional computers in society, the economy and the entire work- the fields of machine learning (training ing system. computers to use data to, effectively, make decisions without additional human input, Computing technologies, in general, are to run search engines, spam email filters, based on a series of assumptions, which are: voice- or facial-recognition technologies or • A technological society could eventu- self-driving cars, for example) and simula- tion technologies. ally achieve the capability of creating a computer simulation that is indistin- What quantum computing is guishable from reality to the inhabit- ants of the simulation. Quantum computing is essentially harness- • Such a society would not do this once ing and exploiting the amazing laws of or twice. These would create many quantum mechanics to process informa- such simulations. tion. A traditional computer uses long strings of bits, which encode either 0 or 1. A quantum computer, on the other hand, uses quantum bits, or qubits. A qubit is a quantum system that encodes 0 and 1 into two distinguishable quantum states. Qubits represent atoms, ions, photons or electrons and their respec- tive control devices that work together to act as computer memory and a processor. But, because qubits behave quantum mechani- cally, we can capitalise on the phenomena of superposition and entanglement. Superposition is the ability of a quan- tum system to be in multiple states at the same time, that is, something can be here and there, or up and down at the same time.18 August 2016 | ElEctronics For You www.EFYmAg.com



information technology Entanglement is an extremely out better ways to overcome deco- Businesses need to be ready for astrong correlation that exists be- herence, while experimentalists are quantum future because it is coming.tween quantum particles—so strong gaining more and more control over The technology could herald radicalthat two or more quantum particles the quantum world through vari- changes for the following areas, tocan be inextricably linked in perfect ous technologies and instruments. name a few:unison, even if separated by great dis- Pioneering work being done today • Safer airplanes. Lockheed Martintances. The particles remain perfectly is paving the way for the upcomingcorrelated even if separated by great quantum era. plans to use its D-Wave to test jetdistances. These are so intrinsically software that is currently too com-connected that these can be said Potential applications plex for classical computers.to dance in instantaneous, perfect • Discover distant planets. Quantumunison, even when placed at opposite Quantum computers will be able to computers will be able to analyseends of the universe. efficiently simulate quantum systems. the vast amount of data collected This will allow to study, in remark- by telescopes and seek out Earth- Such quantum effects are ex- able detail, interactions between like planets.tremely useful to the future of atoms and molecules. This could • Win elections. Campaigners willcomputing and communications help design new drugs and materials, comb through reams of market-technology. Thanks to superposition such as superconductors that work at ing information to best exploitand entanglement, a quantum com- room temperature. individual voter preferences.puter can process a vast number of • Boost GDP. Hyper-personalisedcalculations simultaneously. Where a Another of the many benefits of advertising, based on quantumclassical computer works with 0s and quantum computers over classical computation, will stimulate con-1s, a quantum computer will have ones is searching through a space sumer spending.the advantage of using 1s, 0s and of potential solutions for the best • Detect cancer earlier. Computa-superpositions of 1s and 0s. solution. Researchers are constantly tional models will help determine working on new quantum algorithms how diseases develop.Current status and applications. But the true poten- • Help automobiles drive them- tial of quantum computers likely has selves. Google is already usingQubits could be made of photons, at- not even been imagined yet. a quantum computer to designoms, electrons, molecules or perhaps software that can distinguish carssomething else. But these are notori- Future uses of quantum comput- from landmarks.ously tricky to manipulate, since any ers are bound only by imagination. • Reduce weather-related deaths.disturbance causes these to fall out of Quantum technologies offer ultra- Precision forecasting will givetheir quantum state (or decohere). secure communications, sensors of people more time to take cover. unprecedented precision and com- • Cut back on travel time. Sophis- Decoherence is the Achilles heel puters that are exponentially more ticated analysis of traffic patternsof quantum computing, but it is not powerful than any supercomputer for in the air and on the ground willinsurmountable. The field of quan- a given task. These technologies are forestall bottlenecks and snarls.tum error correction examines how destined to fundamentally change • Develop more effective drugs. Byto stave off decoherence and combat our lives, and the first commercially- mapping amino acids, for exam-other errors. While quantum comput- available quantum devices are only ple, or analysing DNA-sequencingers have been theoretically demon- now beginning to emerge. data, doctors would be able tostrated to have incredible potential, discover and design superior drugand scientists are working around the Quantum computing has the based treatments.world to realise that potential, there capability to unlock answers to someis much work to be done before these of humanity’s most pressing ques- Conclusionhit the market. tions that are presently unsolvable with current computing technologies. Developed countries are making huge There are quantum computers It is expected that in less than ten investments for the development ofalready, but not of sufficient power years, quantum computers will begin quantum technologies in order toto replace classical computers. While to outperform everyday computers, become the epicentres of this tech-practical quantum technologies are leading to breakthroughs in artificial nology revolution in the near future.already emerging—including highly- intelligence, discovery of new phar- However, quantum computing mighteffective sensors, actuators and other maceuticals and beyond. struggle to impact everyday life as itdevices—a true quantum computer may be suppressed by those opposedthat outperforms a classical computer The very fast computing power to the changes it might bring.is still years away. of quantum computers has the potential to disrupt traditional busi- Theorists are continually figuring nesses and challenge cyber security.20 August 2016 | ElEctronics For You www.EFYmAg.com



tech focus Does Your Car Have a Driver’s LiCenCe Vision Next 100: Rolls-Royce 103EXDilin Anand is a People are, on average, terrible driv- to get a driver’s licence. My team and Isenior assistant ers. How do you solve this prob- are committed to make sure that doeseditor at EFY. He is lem? Do not let them drive or put a not happen.”B.Tech in ECE from machine in its place?University of Calicut, So when these arrive, what wouldand MBA from Christ Self-driving vehicles are not some fu- enable cars to safely roam our streets byUniversity, Bengaluru turistic automotive technology that we are themselves? yet to see. These are cars from the likes of BMW and Tesla with self-driving features Sense of sight on the road. There are two types that are being tested or that are on the road: In order for your car to be aware of its semi-autonomous cars that we already surroundings, it first needs to see where see and fully autonomous ones that are it is standing. expected anywhere between two to 14 years depending on whom you ask. Tesla LiDAR. LiDAR, or Light Detection And CEO Elon Musk and Google’s Sergey Brin Ranging, is one of the most popular and are two people who believe that it will be actively-used technologies that enable self- sooner rather than later. driving cars to see. The most recognised version of LiDAR is the one you see on Chris Urmson, who heads Google’s top of Google’s self-driving cars, and it is driverless car programme, said in a talk, HDL-64E. “My oldest son is 11, and that means in four and a half years he will be eligible Velodyne’s HDL-64E enables obsta- cle detection and navigation with a 360° field-of-view. Enabled by 64 laser beams,22 August 2016 | ElEctronics For You www.EFYmAg.com



tech focusthis is probably one of the best and the cyclist, but LiDAR laser picks it PathFindIR is a compact thermalmost expensive solutions available up, calculates the distance and pre- imaging camera that significantlyright now. vents the car from moving ahead reduces the hazards of night time until the cyclist has passed. driving, and is designed for both Another firm, Quanergy, recent- military vehicles as well as com-ly announced a solid-state LiDAR Cameras. Mercedes F015, about mercial vehicles as an aftermarketnamed S3 that has no moving parts which we wrote last year, does not part. These systems have improvedor micro-mirrors. Instead, it uses an use LiDAR, but a mix of 3D stereo- from mere night vision to be-optical-phased array as a transmit- scopic cameras, radars and ultra- ing able to identify a hazardouster, which can steer pulses of light sonic sensors for its autonomous object or even go as far as alertingby shifting the phase of a laser functions. It is very much possible the object.pulse as it is projected through to set up driver-assistance systemsthe array. S3 is due to be available using just camera data, like how Mercedes had CL550 a fewin September. Land Rover Discovery Sport does years back that would identify with a Bosch stereo video camera. pedestrians on the road and flash The major benefit of using Li- Its spatial measurements and video them with four blasts of divertedDAR systems is that the data these signals provide enough data to headlight while highlightinggenerate is easier to compute and them with white brackets on users’ screens.Crash under a brightly-lit sky While LiDAR and cameras areA fatal crash occurred late June this year, when a Tesla Model S running in its almost great for generating an accurateautonomous autopilot mode rammed into a trailer lying perpendicular on the road. map of the car’s surroundings, these are not ideal for monitoringTesla’s statement says, “Neither autopilot nor the driver noticed the white side of the the speed of other moving objectstractor-trailer against a brightly-lit sky, so the brake was not applied. The high ride in real-time. So what do we do?height of the trailer combined with its positioning across the road and the extremely-rarecircumstances of the impact caused Model S to pass under the trailer, with the bottom of Sense of hearingthe trailer impacting the windshield of the car.” Just like Tesla, which uses radar asIs India ready one among its suite of electronic senses with which the car finds itsIndian roads are in a unique situation when compared to those in other countries. way around town, there are otherWhile some of our roads feature full road markings and signage, others make you think vendors too who plan to use auto-whether the road you are driving on was borrowed from Harappa or Mohenjo Daro motive radar.archaeological sites. Radar. CMOS seems to be theA good number of development teams sit in India working on technology that can help in in thing in the world of automo-the building of self-driving cars, but a few, if any, car manufacturers believe that our roads tive radar. NXP has millimetre-are not ready to take autonomous vehicles—at least for a few decades! wave technology for its automo- tive radar, which is based on aprocess as compared to the data calculate, for example, the distance digital CMOS process that was notgenerated from a camera. These to vehicles ahead. believed possible. The solutioncan also work in places where covers 76GHz to 81GHz range.GPS and mapping data are not This is nothing new, of course,really accurate. Volvo Group has as Subaru has been marketing Imec and Vrije Universiteitan autonomous FMX heavy-duty their own version since 2010, and Brussel from Belgium announcedvehicle designed to work in un- Continental has their own forward- some time back what they thenderground mines without the need looking braking system with claimed to be the world’s firstfor a driver. stereoscopic cameras that is just 79GHz radar transmitter based as old. on digital 28nm CMOS. “With an Of all the demonstrations that output power above 10dBm, thewe at EFY have come across of Infrared or thermal imaging transmitter front-end paves theLiDAR usage, perhaps the best is cameras have been available that way for full radar-on-chip solu-when the car picks up a cyclist can detect hidden objects like peo- tions for automotive and smartwaiting to cross the road on the ple or animals in total darkness, environment applications,” statedother side of a pickup truck. Driv- smoke or fog-like conditions when the release.ers in the car are not able to see normal detection systems may not easily pick these up. FLIR Systems Freescale has a 77GHz pack- 24 August 2016 | ElEctronics For You aged radar front-end chipset but www.EFYmAg.com



tech focusthey use SiGe technology. The standardised frequency match to ensure a precise posi- Infineon’s SiGe based Radar band of 5.9GHz (IEEE 802.11p) tioning accuracy, low latency and derived from Wi-Fi as the technol- dead reckoning.System IC (RASIC) series consists ogy base for wireless communica-of a group of highly-integrated tion enables direct, low-latency U-blox lists an automotive-functions for 76GHz to 77GHz information exchange between grade V2X transceiver modulerange for automotive radar. vehicles and infrastructure. IEEE called THEO-P1 series for infra- 1609 family of standards for Wire- structure and vehicles, which is in GPS, V2X and everything else. less Access in Vehicular Environ- compliance with WAVE and ETSIWhile these are more for speaking ments (WAVE) defines the archi- ITS G5 for American and Europeanthan merely listening, GPS and tecture, communications model, operations. U-blox claims that thisV2X enable an intelligent trans- management structure, security chip has a range of one kilometre.port system where all vehicles mechanisms and physical accessand infrastructure systems are for high-speed (up to 27Mb/s), Sense of awarenessinterconnected with each other.This connectivity aims to provide While having cameras to see details on the road are important,Driverless cars may be safe, but are these secure those that come with processing software to pick up lane markersAlthough this means that car security is at risk all the time, automobile manufacturers and monitor your distance fromhave also taken some steps to safeguard vehicles. One such initiative is known as these are what enable cars andE-Safety Vehicle Intrusion Protection Applications (EVITA), which was developed by car other vehicles to drive them-manufacturers in the European Union. “This is a hardware solution. They have made selves. If you stray over the linehardware that has encryption facilities and all that, and which can be included into any without signalling, you will hearmicrocontroller intended for automotive applications,” he said. There is also a software a warning tone or feel a physi-solution called OVERSEE (an open vehicular secure platform), which involves the cal alert such as a vibration inseparation of software applications from hardware components. the steering wheel or seat. More advanced lane-keeping assist —Dr S.K. Sinha in a talk delivered at Electronics Rocks 2016 systems selectively apply brakes or nudge the steering to guide youUp next, trucks back if you are wandering.The race is already on to put driverless trucks on public roads. In May 2015, the first In autonomous mode, suchself-driving truck rolled through Nevada. Of the several tests around the world since then, as in Tesla with autopilot, athe most interesting is a convoy that drove across Europe using a new technology called front-facing radar, a camera withplatooning. It connects trucks using Wi-Fi, sensors, GPS and cameras and allows the image-recognition capability andleading vehicle to dictate speed and direction, while the rest automatically steer, speed up 360-degree ultrasonic sonar willand slow down. pick up lane markings on the road as well as other vehicles to steermore precise knowledge of the short-range (up to 1000m), low- and control vehicle speed.traffic situation across the entire latency wireless communicationsroad network. in the vehicular environment. In a talk delivered at Electron- ics Rocks 2016 conference, Dr Continental has been at it since Primary architectural com- S. K. Sinha said, “Thirty years2006. Their system can be comple- ponents defined by these stand- ago, software in the cars wasmented by the intelligent locali- ards are OnBoard Unit (OBU), zero—there was no software.sation sensor M2XPro or Motion In- Road Side Unit (RSU) and WAVE And, in just a short period of 30formation to X Provider. Fusion of interface. Dedicated Short-Range years, the amount of softwaresensor data about speed, steering Communication (DSRC) is a com- has gone to ten million lines ofangle, GNSS and inertial infor- munication technology that works code, in low-end cars. If you talkmation, along with position and in the 5.9GHz band in the USA and about Audi, Mercedes or BMWtiming information are essential China or 5.8GHz band in Japan cars, these have hundred millionfor V2X communication to detect and Europe. lines of code today. Thousands ofand evaluate potential threats. This functions are being realised withenables a perception, detection and ST has a V2X system using software today.”assessment of road obstacles and their co-developed Autotalks V2Xdangerous situations even before Communication processor along “The biggest worry is if thethese can be noticed optically. with ST’s multi-constellation GNSS software controlling the cars receiver, Teseo, that builds a perfect have enough information about 26 August 2016 | ElEctronics For You www.EFYmAg.com

the world around it and how it reacts to situa- ElEctronics For You | August 2016 27tions,” says Sanjay Gupta, India country manager,NXP India. NXP has four broad umbrellas, thatis, sense, think, act and Big Data. Radar, visionand secure V2X help the vehicle in its sensingcapabilities. The self-driven car thinks on process-ing, sensor fusion and security, and acts throughpower-train, chassis and braking. Big Data comesin the picture to provide necessary infrastructure,security and digital networking. Even when these vehicles are capable of fully-autonomous driving, it might take quite some timefor it to show up on highways until the necessarylegislation and policies are passed. In the mean-while, mines and other closed industrial areas areripe for a disruptive transportation technology thatcan remove the unpredictability of humans whilesimultaneously reducing danger to humans work-ing in dangerous locations such as mines.NFC and the Ethernet, in carsNFC is now playing a role in automotive becauseof mobiles that are starting to adopt NFC, and weknow the importance of mobiles and how con-venient these are. “Automotive is picking up NFCbecause an automobile can have multiple peoplesitting in it and NFC is more convenient,” saidRajiv Kapur, managing director, Broadcom India,in an interview with EFY. The whole universe of the Ethernet had previ-ously been outside the car. Automotive world hadnot touched the Ethernet world until now. Thefirst vehicle on the streets in the world to use theEthernet in it was BMW X6. The whole purpose is to leverage the universeof the Ethernet to give better vehicles. For exam-ple, the rear camera can be an Ethernet basedcamera. Kapur added, “We actually invented howthe Ethernet can be distributed over thin cables.It is a standard now but we invented it. Once theautomobile industry got that invention, whichis now a standard, it started to adopt it. Nowthere are many more vehicles with the Ethernetin them.”Your car will have a licence to killA new study published in Science shows thatpeople want self-driving cars to be programmedto minimise casualties during a crash, even if itcauses the death of the rider. Trouble is, the samesurvey shows that people do not actually want toride in cars that are programmed this way. Thatis obviously a problem, and we are just going tohave to get over it!www.EFYmAg.com

Power SuPPly Net-MeteriNg iN iNdia:Way To A Secure Power FutureTanya Batra is Power cuts in homes is not NEWS to cess electricity produced by a solar powervice president us. If you have been living in India, system is fed back to the grid.- marketing, it is something we have all grownSunkalp Energy up with. Things may have improved from Are you aware of the concept of all-night power cuts to perhaps four-hour net-metering? Net-metering is a bill- power cuts in a day in peak summers. ing arrangement with your utility that But, we are yet to see the day without determines how you will get credit for any any power cuts. excess renewable electricity delivered by you to the grid. Simply put, you get paid If you have been living in residential back by your electricity provider for the complexes/apartments, you may not excess power your solar power system have felt it because the societies provide generates. This power is measured using a backup using DG gensets. However, the net-meter, which is a two-way meter that grid still does not function as a reliable measures what you draw from the grid source of energy. and what you feed back. The net-metering process is automatic. But, there is one state that has done wonders—Gujarat. It was the first state This is a brilliant concept, simply to have an enforced solar policy. Since because it is a great way to reduce bills in 2009, it has built a capacity of 957MW and is now a state with 24/7 electricity. Comparison of Grid Tariff (Commercial) with LCOE In terms of capacity, Rajasthan has over- 14 taken Gujarat. But, Gujarat still stands as a role model in the overhaul it has gone 12 through. One of the main reasons for its success is its connectivity to the grid. Ex- 10 8 6 4 2 0 Delhi Haryana Uttar Punjab Rajasthan Gujarat Maharashtra Pradesh Commercial tariff LCOE of Solar (Com.) Comparison of Grid Tariff (Residential) with LCOE 16 14 12 10 8 6 4 2 0 Delhi Haryana Uttar Punjab Rajasthan Gujarat Maharashtra Pradesh Residential tariff LCOE of Solar (Res.)Fig. 1: Areas (shown in Assumptions: green) where • Tariff from respective states tariff orders (this may net-metering guidelines or may not include all taxes and fixed charges) are are in place indicative figures • Average size of a solar system considered is 28 August 2016 | ElEctronics For You 100kW for the commercial segment and 10kW for the residential segment • Energy charges have been used from the respective tariff orders of states Fig. 2: Comparison of grid tariff with LCOE www.EFYmAg.com



Power SuPPlyareas that have high power tariffs Solar InStallatIon CapaCIty from the grid at all, that is depen-such as New Delhi and Mumbai. dent on your state’s regulations.There are a total of 20 states and Indian state allotted transformer Solar power plant For example, in Haryana you cansix union territories with defined capacity size allowed install a capacity equalling 100net-metering guidelines. The map per cent of your connected load.shown in Fig. 1 marks out the Haryana 30% 100% However, in New Delhi, you haveareas where net-metering guide- the option of exceeding your New Delhi 20% No limit Uttar Pradesh 15% 100%lines are in place. So India does Maharashtra 40% 100% connected load by paying extralook progressive in achieving its Punjab 30% 80% charges. The table gives you the100GW target for solar! Gujarat 30% (as in the draft 50% figures of how much solar you If we look at the northern policy) can install as a percentage of thestates of India and compare their Rajasthan 30% 80% connected load.tariffs in the commercial and The allotted transformerresidential sectors, we can clearly tween 15 per cent and 30 per cent. capacity is filled on a first-comesee that levelised cost of electricity Maharashtra as an exception has 40 first-serve basis. So if you are look-(LCOE) from solar panels is much per cent allotted transformer capac- ing to benefit from rooftop solar forless than the tariffs that are being ity for solar. The payback period reducing your bill, you might wantpaid by top-slab customers. It is also largely depends on the tariff of the to consider doing this soon. Onceevident that it makes sense for com- particular state. The higher the grid the allotted transformer capacitymercial customers, and residential is tariff, the lower the payback period. is saturated, you may not be ablecatching up, too. Also, the question is about how to connect your system to the gridNet-metering specifications much of your consumption can be for a while. You can take a look at offset using solar and how much Sunkalp Energy’s website (www.As a general trend, the allotted you are allowed to install. So if you sunkalp.com), which is an aggrega-transformer capacity for grid-con- have been thinking that you will tor that would help you go solar andnected solar power plants is be- install only solar and not consume connect to the grid.30 August 2016 | ElEctronics For You www.EFYmAg.com



healthcareElEctric Brain Stimulation Needs caution Dr S.S. Verma Electric dominance of the brain work- Electrical brain stimulation was first is a professor ing is well confirmed and estab- used in the first half of the 19th century at Department lished by health and neural sciences. by pioneering researchers such as Luigi of Physics, Sant Electric signals within the brain not only Rolando (1773 - 1831) and Pierre Flourens Longowal Institute govern/control the working of the human (1794 - 1867), to study the brain localisa- of Engineering and body, but according to recent medical stud- tion of function, following the discovery Technology, Sangrur, ies, these signals with suitable electric brain by Italian physician Luigi Galvani (1737 - Punjab simulation techniques can be controlled to 1798) that nerves and muscles were electri-Transcranial direct enhance the desired activities of the human cally excitable.current stimulation body like motion, memory, health, peace and more. This article aims to bring to the In the following century, the technique reader such useful outcomes of electric was improved upon by the invention of the brain simulation, but with caution that such stereotactic method by British neurosurgeon technology should be used under proper pioneer Victor Horsley (1857 - 1916) and medical expert supervision. by the development of chronic electrode implants by Swiss neurophysiologist Walter Electric brain stimulation in its current Rudolf Hess (1881 - 1973), José Delgado form may be relatively new, but humans (1915 - 2011) and others, by using electrodes have been tinkering with the brain for centu- manufactured by straight insulated wires ries. Electrical brain stimulation, also referred that could be inserted deep into the brain. to as focal brain stimulation (FBS), is a form of electrotherapy. This technique is used in Two-photon excitation microscopy has research and clinical neurobiology to stimu- shown that micro-stimulation activates late a neuron or neural network in the brain neurons sparsely around the electrode even through direct or indirect excitation of its cell at low currents (as low as 10μA), up to membrane by using an electric current. distances as far as 4mm away. This hap- pens without particularly selecting otherSome studies show that stimulating the brain with electricity can immediately boost memory, focus, neurons much nearer the electrode’s tip.energy and vigilance. Researchers say that it also shows promise as a means of treating drug-resistant This is due to activation of neurons beingmental illness like depression, as well as conditions like epilepsy and chronic pain. Here’s how it works: determined by whether these have axons or dendrites that pass within a radius of 15μmAnode Wires near the tip of the electrode. As current is increased, volume around the tip that acti-The anode, or positively- Two electrodes can vates neuron axons and dendrites increasescharged electrode, provide different types of and, with this, the number of neurons thatcan stimulate neuronal stimulation, depending are activated. Activation is most likely toactivity in different parts on where these are be due to direct depolarisation rather thanof the brain placed. Together, these synaptic activation. make a complete circuitcAthode Techniques of electric brain device stimulationThe cathode, ornegatively-charged A battery-powered Medical experts and companies haveelectrode, can inhibit device delivers a developed a variety of non-invasive brainbrain-cell activity constant elecrical stimulation technologies such as cranial current of up to electrotherapy stimulation (CES), deep 2mA (milliamperes). brain stimulation (DBS), transcranial direct Researchers have current stimulation (tDCS), electroconvul- demonstrated that it sive therapy (ECT), functional electrical is safe to apply this much current for up www.EFYmAg.com to 30 minutes a day. DIY brain stimulators frequently use a 9-volt battery as a power sourceSource: Wright StateResearch Institute,Johns HopkinsMedicine32 August 2016 | ElEctronics For You



healthcarestimulation (FES), magnetic seizure while others suggest the technique been approved for treating depres-therapy (MST), vagus nerve stimu- has little effect. That has not stopped sion and migraines.lation (VNS) and deep transcranial adventurous amateurs from testingmagnetic stimulation (deep TMS). home-made devices on themselves, Effects of electric brain though this is not recommended. stimulation tDCS is getting loads of attention Scientists are still investigating howfrom early adopters who rave about tDCS works, but the reigning hypoth- Focused thinking, better memory,its potential, and scientists who are esis is that it changes the excitability deeper sleep, relief from depressiontrying to unravel what it can and can- of a particular brain region. Depend- and reduced stress are some ben-not do. It is a non-invasive form of ing on the direction of the current, efits of electronic stimulation for thebrain stimulation that involves passing stimulation could make neurons in a mind and brain as mentioned in thea current between electrodes on the particular area of the brain more or literature on the Internet by compa-scalp. The technique is one of a num- less likely to fire. nies dealing with the development ofber of technologies being tested to see different types of the brain stimula-if it can enhance cognitive functions Recent studies have focused on tion devices.such as boosting the performance of using tDCS to boost the performancedrone pilots or image analysts. of image analysts for the military. Popular electric brain stimula- The study found that participants tion methods that are used to boost According to the experts, the who received training and stimula- brainpower are detrimental to IQcurrent is set to about 2mA, which scores. Using a weak electric currentis about 1000 times less than the Electrical stimulation devices at Oxford University in an attempt to boost brainpowerelectrical current that flows through can have currents placed on various parts of the or treat conditions has becomea typical iPad charger, and only brain (Image courtesy: www.bbc.com) popular among scientists and do-it-about 1/50th of that current makes yourselfers, but a new study showsit through the skull to the brain. The tion were about 25 per cent more ac- that using the most common formstimulation is said to last for about curate in identifying the objects than of electric brain stimulation has aten minutes, and is aimed at the right those without stimulation. Some statistically significant detrimentalinferior frontal cortex and the right studies claim to have found benefits effect on IQ scores.anterior temporal lobe, which are in everything from mental arithmeticbrain areas thought to be important to memory; other studies have found Strong electric currents mayfor learning. no evidence of cognitive effects from cause a localised lesion in the ner- a single session of tDCS. vous tissue instead of a functional A mild stinging sensation is felt reversible stimulation. This propertywhere the electrode is attached to Research on tDCS is not limited has been used for neurosurgicalthe head. This is thought to be a to seeking cognitive boosts. Many procedures in a variety of treatmentsnormal feeling, but if the sensa- scientists are also investigating its such as for Parkinson’s disease, focaltion continues, it is better to turn efficacy in treating mental disorders epilepsy and psychosurgery. Some-off the connection and try to get a such as traumatic brain injury and times, the same electrode is used tobetter connection. schizophrenia. However, there is no probe the brain for finding defective administrative approval for the use functions, before passing the lesson- Next, people notice a slight taste of the technique. ing current (electro-coagulation).of metal in their mouth, a com-mon side effect of tDCS, according Similarly, TMS uses a magnetic A comprehensive review of theto experts. coil to induce small electrical cur- research on electrical stimulation rents in the brain. In contrast to of the brain gives a list of different Although this is an experimental tDCS, TMS actually causes neurons acute impacts of stimulation depend-method, it is widely regarded as safe to send signals or spike, and it has ing on the brain region targeted.and does not appear to cause any Following are some examples of theshort-term harm. The most common effects documented:side effects of stimulation includetingling or skin irritation and see- Sensory. Feelings of bodying phosphenes (light rings or spots tingling, swaying, movement, suf-not produced by actual light). Other focation, burning, shock, warmth,side effects include fatigue, headache paresthesia, feeling of falling,and itching under the electrode. In oscillopsia, dysesthesia, levitation,rare cases, people experience nausea sounds, phosphenes, hallucinations,or insomnia. micropsia, diplopia and more Some studies have found impres- Motor. Eye movements, locomo-sive gains in performance from tDCS, tion, speech arrest, automatisms,34 August 2016 | ElEctronics For You www.EFYmAg.com



healthcarelaughter, palilalia, chewing, urge to chest area, and the extension wire is Preliminary research suggestsmove, crying without feeling sad, etc tunneled under the skin. The pulse that electrical simulation can im- generator sends out intermittent prove attention as well as have a Autonomic. Blushing, mydriasis, electrical stimulation to the elec- positive impact on people with cog-change in blood pressure and breath- trode in the thalamus, which inhib- nitive impairments and depression.ing, apnea, nausea, tachycardia, its or partially relieves the tremor. Research has also highlighted thatsweating and the like The generator can be turned on and electrical brain stimulation could off with a magnet, and needs to be have favourable effects on humans, Emotional. Anxiety, mirth, feel- replaced every three to five years. but some companies are sellinging of unreality, fear, happiness, an- such devices online, leading to callsger, sadness, transient acute depres- Similar methods have been used to regulate the technology. If usedsion and hypomania, among others to treat chronic pain that responded in the wrong way, these devices unfavourably to conventional thera- could be harmful. Cognitive. Acalculia, paraphasia, pies. A remote transmitter allowedanomic aphasia, recalling memories, these patients to trigger electric We need to know how long togoing into a trance, out-of-this-world stimulation to relieve their symptoms stimulate, at what time to stimulateexperience, conduction aphasia, on an as-needed basis. Patients with and what intensity to use. Electricalhemispatial neglect, reliving past failed back syndrome, trigeminal stimulation is used in a controlledexperiences, agraphia, apraxia and neuropathy (pertaining to the fifth environment for no more thanso on cranial nerve) and peripheral neurop- ten minutes at a time and only on athy fared well for pain control with participants who have passed strictMedical applications of electric this treatment, while patients with medical checks. Scientists are, afterbrain stimulation spinal cord injury and postherpetic all, applying electrodes to the brain, neuralagia (pain along the nerves fol- which they say could have someElectrical stimulation of the brain is lowing herpes) did poorly. unintended results. For example,a relatively new technique used to different brain regions than thosetreat chronic pain and tremors asso- Implantation of electrodes into intended might be affected and, inciated with Parkinson’s disease. It is the brain carries risks of hemor- some instances, stimulation couldadministered by passing an electrical rhage, infarction, infection and cer- impair rather than improve functioncurrent through an electrode im- ebral edema. These complications if the polarity of the stimulationplanted in the brain. While implanta- could cause irreversible neurological is reversed.tion of electrodes in the brain is used damage. Patients with an implantedto treat or diagnose several disorders, electric brain stimulation tremor- What is even more worrisome isthe term electric brain stimulation control device may experience head- that people are increasingly makingis limited to the treatment of trem- aches, disequilibrium (disturbance DIY brain stimulation kits them-ors and as a pain-management tool of the sense of balance), burning or selves. This puts the technology infor patients suffering from back tingling of skin or partial paralysis. the realms of clever teenagers.problems and other chronic injuriesand illnesses. Warning over electrical brain Another concern is that the stimulation science behind these devices is not An electric brain stimulation ready for the commercial market,tremor-control device used in treat- Preliminary research on the ef- and companies are jumping oning people suffering from Parkinson’s fects of tDCS has spurred a host of the hype of research that is notmay interfere with or be affected by scientists (and amateurs) to explore quite ready for the world. Anycardiac pacemakers and other medi- the possibility of improving cogni- device with medical claims thatcal equipment. As a result, patients tive function, increasing reaction it is meant to affect the biologicalwith other implanted medical equip- times and treating mental illnesses function should be appropriatelyment may not be good candidates through carefully-applied electrodes. regulated.for the therapy. Electrical stimulationof the brain, or deep brain stimula- Research has shown that by Suggestions of increased atten-tion, is effective in treating tremors delivering electricity to the right tion and alleviation of certain medi-in up to 88 per cent of Parkinson’s part of the brain, we can change the cal conditions mean that interest indisease patients. threshold of neurons that transmit electrical stimulation is bound to information in our brain and, by increase, but if the research con- An electrode is implanted into the doing that, we can improve cognitive tinues to show promising results, itthalamus (part of the brain) of the abilities in different types of psycho- is clear that electric brain simula-patient and is attached to an electric logical functions. The idea is to make tion will need to be treated withpulse generator via an extension the neurons more likely to fire. some caution.wire. The pulse generator is im-planted into the patient’s pectoral, or36 August 2016 | ElEctronics For You www.EFYmAg.com



satcomIRNSS: India’s Attempt At Gaining INdepeNdeNce FRom GpS Saurabh Durgapal “Indian Regional Navigation Space- Facts and figures is working as craft System (IRNSS) is the Indian technology navigation system that envisages Budget: ` 14.4 billion journalist at EFY. the establishment of the regional navi- This article has gation system using a combination of Coverage: 1500km from Indian boundary been written geostationary orbit (GEO) and geosyn- with inputs from chronous orbit (GSO) spacecraft,” reads Control centre: ISRO Navigation Centre at Byalalu Dr Vyasaraj G. Indian Space Research Organisation near BengaluruPortable GNSS (ISRO) website on self-reliance with ansimulator indigenous navigation system. What does Offered services: Standard Positioning Service this mean for the common man? (public users) and Restricted Service (authorised users) We open Google Maps application on our phones and search for a place. The Project timeline signal travels all around the world, to the GPS control station in the USA. Processing “It was back in 2003 that the project takes place at their end and, after some was beginning to take form,” recalls Dr deliberation on their part, we receive cer- Vyasaraj G., senior manager - GNSS and tain co-ordinates. This takes some time. aerospace electronics, Accord Software. “The main focus behind developing an Also, according to conspiracy theorists, indigenous system was to remove depend- security agencies get to know if you ac- ence on the American GPS system. After cess anything disconcerting. With IRNSS, announcement of the project we were to the time to access is expected to be much design simulators that could simulate the lesser and the said theorists can feel a perfect environments for testing the satel- bit safer, as this information will now be lites, and this began the race for develop- processed by Indian agencies. ment of IRNSS receiver modules. “After finalisation of the systems, we had receiver modules being developed to test signal characteristics before the first satellite was in place. By the end of 2012, we had developed receiver modules, even before the satellites were launched,” adds Dr Vyasaraj. By 2008, project details were finalised and the expected date for the system to go live was set to end of 2015, with the first satellite being launched in 2011, and the next every six months. After a delay in the original timeline, the first satel- lite, IRNSS-1A, was launched on July 1, 2013, and the others followed suit. The last satellite, IRNSS-1G, was successfully launched on April 28, 2016, from Satish Dhawan Space Centre (SDSC), SHAR, Sriharikota launch site. Development and deployment The proposed system consists of a constel- lation of seven satellites and a support38 August 2016 | ElEctronics For You www.EFYmAg.com



satcom Satellite equipment and services Satellite payloads consist of rubidium atomic clocks and other electronic equipment to generate navigation signals. Employing both L5 (1176.45MHz) and S band (2492.028MHz), the system provides two kinds of services, namely, Standard Positioning Service (SPS) and Precision Service (PS). The SPS signal is modulated by a 1MHz Binary Phase Shift Key (BPSK) modulation, whereas PS uses Binary Offset Carrier (BOC). Satellite detailS nae for high-accuracy needs,” says Dr Vyasaraj on using multiple-frequency Name launch date launch signals for location tracking. vehicle IRNSS-1A July 1, 2013 PSLV-C22 He adds, “IRNSS systems have IRNSS-1B April 4, 2014 PSLV-C24 been working on adding L1 band for IRNSS-1C October 16, 2014 PSLV-C26 navigation. And very soon we may IRNSS-1D March 28, 2015 PSLV-C27 have three signals to further im- IRNSS-1E January 20, 2016 PSLV-C31 prove location accuracy for naviga- IRNSS-1F March 10, 2016 PSLV-C32 tion systems.” The system uses grid IRNSS-1G April 28, 2016 PSLV-C33 based ionosphere-related corrections for single-frequency users (L5/S) to ground segment. Three satellites are improve location accuracy. located in GEO and the other four in inclined GSO. Such an arrangement Testing and development means continuous radio visibility at all hours for Indian control stations. Before completion and launch of satellites, there is the need for testing “We typically have two sig- the design parameters and the func- nal frequencies to overcome the tioning modules. Design simulators problem caused by disruption in have helped play a huge role in this the signal, which is caused by the stage of the development. “We have ionosphere. This increases the size a simulator from Accord Software of the module due to the integration capable of generating and measuring of two separate antennae for the signal conditions upon reception. The two frequencies. Hence, a solution device hardware is compatible with is to use a single antenna, meaning, American GPS, Russian GLONASS, a single frequency being used for Indian IRNSS, European Galileo and navigation. Using a single antenna Chinese Bie-Deu/BDS. causes very low accuracy and can show a position difference by 10 “The simulator also has support metres to 15 metres. for several SBAS systems. We can modulate and test signal parameters “Addition of a second signal during various stages of transmis- reduces this to about five metres to sion. The simulator generates signal eight metres. Hence, a system inte- distortions similar to the actual con- grator could decide on designing the ditions and gives results, which can system to reduce system complexity help fine-tune GNSS equipment,” with a single antenna system for low- says Dr Pratibha B.A., project leader accuracy needs or placing two anten- at Accord Software. For field-testing purposes, there40 August 2016 | ElEctronics For You www.EFYmAg.com



is a portable version of the device, satcom we can go for the single antennawhich has an RJ45 interface for system and reduce cost and size ofconnecting to a computer system. Reducing the chip size the modules”.The device can be controlled by acomputer application loaded with A major deterrent with current chips Other ways to miniaturise thecustom firmware. The portable is the size. With reduction in size chipset could come up in the nearsimulator has the same features as compatible with wearables, we have future so that integration is eas-the other device with the added hopes for a more compact system. ily possible into a smartphone or abenefit of a compact design. Let us take a look at how this minia- wearable gadget. turisation could happen. Along with simulators, devel- What the system looks likeopment of an IRNSS-compatible Majority of GNSS modulesreceiver is also underway. G3I, employ two distinct frequencies to IRNSS system blankets the Southa credit-card-sized receiver chip, Asian region, with more frequentwith support for IRNSS along with “The main focus updates compared to earlier sys-other constellations, is currently behind developing an tems. The precise and faster locationunder development. indigenous system was in real-time, along with the atomic to remove dependence clock onboard the satellite provid-Equipment and the challenges on the American GPS ing higher timing accuracy, provides system.” a major boost to high-accuracy“At present, IRNSS is not common requirement applications.in the market, which is going — Dr Vyasaraj G., senior manager - GNSSto change in the coming years. and aerospace electronics, Accord Software With the added featureComplete testing and fi- of grid based ionosphere-nalisation of the constellation SimGUI simulator related corrections forshould be done in the next six removing issues causedmonths and then we should overcome the errors in the received due to interference by thesee more IRNSS chips in the signals due to interference by the ionosphere, this system ismarket,” says Dr Vyasaraj. ionosphere. With only a single at par with GPS+WAAS,After the launch of IRNSS-1G frequency, the difference is of a few Galileo+EGNOS and MSASin April, dependence and test metres, which is not an issue with systems around the world.cases for the constellation are wearables or end users.being run in earnest. Hope- Tracing the track aheadfully, in the next few months On a day-to-day basis, wethe system will open for should be able to track a device to IRNSS is at present in thepublic use. a particular building or a particular deployment phase. With street, which can be easily done heavy R&D in the field of an The challenge when designing with the help of a single antenna/ IRNSS-compatible chip miniaturi-the receiver is to keep in mind the frequency module, thus reducing the sation, we will see some excellentform factor along with support for space required on the module for IRNSS receiver modules in the com-other GNSS systems. “Any manufac- the other antenna. ing years. “It will take about twoturer who has successfully stayed in years for the system to be widelythe market has done so by adopting With grid based ionosphere popular with the end user. Till thenand developing the latest patterns. corrections, this is significantly we will see a lot of developments inReducing the form factor to the reduced. Additionally, Dr Vyasaraj the area, and by the time the mar-level of wearables while improving points out, “When we are inside ket demand for IRNSS-compatibleaccuracy and keeping latest updated a room, we do not require such products increases, we will have asupport, and reducing cost mechan- high precision as provided by the very wide array of products,” addsics, are some of the factors that keep double antennae system. Here, Dr Vyasaraj.a manufacturer in the market,” ac- Development of IRNSS will becording to Dr Vyasaraj. an added advantage to the Indian defence systems in preventing an- At present, we have a compara- other Kargil-like fiasco. With Maketively large chip for IRNSS receivers in India initiative, development ofwhere the entire module is tablet- such chips will take priority, andsized. Reduction in chip size with we will have many indigenoussupport for other constellations is products to work with in the yearsexpected in the near future. to come.42 August 2016 | ElEctronics For You www.EFYmAg.com



Manufacture Part 2 of 5 Electromagnetic Compatibility: Multi-layer PCB DesigningChetan Kathalay is In the first part we touched base on speeds is the rise time of the clocks, whileworking as scientist multi-layer PCB designing. In this part the other is the speed of propagation ofin Electronics Test we discuss more about the same. the electrons of the current that consti-and Development tutes the clocks.Centre, Pune. He Multi-layer board and high-speedis BE in electronics PCB design Now, the speed of movement of elec-from Nagpur trons in a PCB trace is less that the speedUniversity A multi-layer board is a PCB having sepa- through air (which is the speed of light) rate layers for power, ground and circuit since the field surrounding the electron tracks. It facilitates the use of entire copper has to travel through the PCB material layers for power and ground connections that creates a drag. The equation given called power planes and ground planes, below gives the relation between speed of respectively. This decreases their inductance wave Vw along a PCB trace surrounded and impedance, allowing the use of high by PCB material to its speed C through clock and signal frequencies and reducing ground noise. A rule of thumb is that, all a trace surrounded by air. εr is relative other things being equal, a four-layer board will produce 15dB less radiation than a two- permittivity of the PCB material. layer board. Vw = C New techniques employed in design and manufacturing of PCB circuits have, on one √εr hand, made it possible to drastically reduceFig. 6: Propagation delay the size of the PCB. On the other hand, how- For example, speed of an electromag- ever, clock frequencies have also increased netic field in a trace surrounded by air is Trace <3” dramatically, resulting in very fast rise times about 30.5cm (12-inch) per nanosecond Clock (or short edge rates) of clocks. Such short (ηs). But when the trace is laid on an driver edge rates mean that decreased PCB dimen- sions have started to have significant effects epoxy PCB (with εr of 4), speed decreases Trace >3” on signal voltages and currents. to 15.2cm (6-inch) per nanosecond. High-speed circuits are those circuits Now, consider a clock whose rise that use clocks of fast (or small) rise times. But how does one define high speed? Well, time is 1ηs, and if dimensions of a PCB the term high speed is relative, where one are greater than half the length traversed is essentially comparing two speeds. Take by this clock in 1ηs (that is, greater than clocks, for example. One of these two 7.6cm or 3-inch), track lengths will start to have significant effects on voltages. Let Y us see how. X Fig. 6 shows a typical clock with rise time of 1ηs. In this time, current associ- 1ηs ated with this clock will travel 15.2cm (6-inch) along the track. Now, if the PCBClock dimension is less than 7.6cm (3-inch),driver reflected wave (wave will be invariably re- flected if track changes direction or there is increase or decrease in track width) will arrive in less than 1ηs (point X in Fig. 6), that is, at a time when the driver is still ramping the pulse up into the trace. Because of driver inertia, reflected pulse will not have any effect on incident pulse. But if PCB dimensions (or track dis-44 August 2016 | ElEctronics For You www.EFYmAg.com



Manufacturecontinuities) are greater than 7.6cm Multi-layer concepts approximately 30dB improvement in(3-inch), reflected pulse will arrive EMC performance.at point Y. Since driven clock is now Let us take a look at some basic termsstable, reflected pulse will have sig- related to multi-player boards that we Reducing fringing fields:nificant effect on incident clock. will be referring to time and again. The 20H rule Hence, for a PCB with dimen- Board or layer stack-up. Stack- Radio frequency (RF) currentssions greater than 7.6cm (3-inch), up is the name given to the order of between power and ground planesclock with rise times of 1ηs will be various etched copper and dielectric will cause emissions at the edges ofconsidered high-speed and, for such layers that make up the board. planes. Such emissions are sometimescases, a radical design approach referred to as edge-fired emissions ortermed as high-speed PCB design Power and ground planes. Mul- fringing fields. These can be reducedusing multi-layer boards will have to ti-layer boards invariably use two by reducing the size of the powerbe followed. layers of un-etched copper that are plane with respect to ground plane. in the form of a continuous sheet, 20H one for power supply (Vcc) and the Ground plane dimensions [on other for ground (return), which are layer 3 in Fig. 7(a)] should exceedL1 normally referred to as power and power plane dimensions by 20H on ground planes. Use of individual all four sides, where H is the distanceVcc L2 H H planes for power and ground lowers between power and ground planes.Gnd L3 VcpcowL2er distribution impedance and This will increase intrinsic self-reso- GandlsLo3 reduces the signal-loop area. nant frequency of the PCB. Decreas- L4 Hence, compared to a two-layer ing spacing between 0V and power PCB, a simple four-layer PCB using planes also reduces fringing fields.Fig. 7 (a): The 20H rule such signal distribution can provide Further decrease can be achieved by using a decap wall around the periph-Fig. 7 (b): Reducing fringing fields Via ery of the power plane and inside the Track1 0V plane periphery by 20H, where H is the plane pair spacing. Plane WWW W WW W W W Reducing cross-talk: The 3W ruleFig. 8: The 3W rule Cross-talk is capacitive couplingFig. 9: Guard and shunt traces of signals from one circuit track to another. This can occur when a high- frequency track is running parallel to a susceptible track. Cross-talk flux and associated capacitive coupling can be reduced by 70 per cent if the two tracks are separated by a distance of 3W, where W is the width of the traces (measured from trace centre). This will cause track flux to terminate on the ground plane below rather than on adjacent tracks (shown as dotted lines in Fig. 8). Guard traces Traces carrying high-frequency sig- nals like clocks can cause coupling of clock harmonics on nearby traces, causing a jittering clock that can lead to problems elsewhere in the circuit. These problems can be reduced by providing guard traces (Fig. 9) on either sides of such a track. Distance46 August 2016 | ElEctronics For You www.EFYmAg.com



ManufactureFig. 10: Equivalent circuit of a via with lowest overall impedance (that is, one with least inductance and Forward current Signal layer 1 highest capacitance). So when a Return current W trace is routed over a ground plane, return currents will flow back rightFig. 11: Dimensions of 0V plane 0V layer 2 underneath the trace, reducing loop area enclosed by forward and return 3W paths, thus reducing differential mode emission and susceptibility.between the guard trace and the shows an equivalent circuit of a via;trace to be protected follows 3W it consists of a series inductor and a 3. A plane underneath a trackrule. Guard trace is connected to shunt capacitor and, hence, acts as carrying high-frequency currents orground at both ends. If it is long, it a low-pass filter. It can cause signal a noisy IC will also behave as anshould be connected to the ground delays and affect the high-frequency image plane. As such fields ema-plane at multiple points λ/20 apart, performance of a board. Hence, vias nating from the track or IC will bewhere λ is the minimum wavelength should be reduced to a minimum. capacitively coupled to the imageof the signal/clock. of the track in the plane rather than Power and ground planes spreading out into space. This willShunt trace reduce common-mode emissions. A continuous sheet or foil of copperThis is a trace located immediately for ground (and power) can provide 4. Capacitive filters for blockingbelow the critical clock trace. It an infinite number of parallel paths common-mode voltages are normal-need not be connected to ground. and, hence, provide least-possible ly mounted between tracks enteringBest isolation can be obtained by inductance. At higher frequency, the board and 0V reference. Theseproviding both guard and shunt skin effect also starts to play its role, bypass common-mode currents totraces, the former providing isola- causing an increase in resistive part ground, and a ground plane pro-tion by terminating magnetic field of impedance. vides the ideal low-impedance pathlines (shown as dotted lines in Fig. for these currents to ground.9) and the latter providing isolation A plane can provide a very largeby terminating electric field lines. surface area and least-possible Size of 0V plane resistance. A ground plane thereforeImage planes is the single-most cost-effective solu- Size of a 0V plane must be such tion to reduce ground path imped- that it does not only lie beneath allAn image plane is a plane physically ance and solve most EMC problems. components and traces of a circuitadjacent (immediately below) to the but also extends beyond these onsignal routing plane. It provides a Functions of a ground plane all sides of the PCB by as much anlow-impedance path for RF cur- amount as possible. This is be-rents and reduces emissions since Ground plane serves the following cause, although forward currentsRF currents use the plane instead of EMC and signal-integrity functions: through a trace are constrained toair. Power supply and ground planes flow in the trace, return currentsnormally behave as image planes, 1. It has very low RF impedance flowing through a plane beneathalthough separate image planes can and, hence, can provide devices and the trace can spread out in thealso be provided. circuits with stable voltages at RF, plane on either side of the trace. So which can be distributed evenly to a edge of the ground plane shouldVia inductance large number of devices and compo- extend more than three times the nents by avoiding voltage drops. trace-to-plane spacing (or threeEach via in a board introduces times the track width).additional inductance of 1ηH and 2. RF return currents flow viacapacitance up to 0.5pF. Fig. 10 0V reference and, if a plane is used, Openings and discontinuities return current can take whichever in ground plane path it wants to, but prefers a path Ground planes, as far as possible, should be continuous throughout. In a practical scenario, this is virtually impossible since anti-pads have to be provided in the ground plane. This causes the ground plane to be perforated, thus increasing its48 August 2016 | ElEctronics For You www.EFYmAg.com



Manufactureinductance. The situation can be Signal layer 1controlled, first by restricting theurge to have tracks that change lay- Good Better Still Besters, second by optimising the size of Betteranti-pads (<1mm) and third by using Poormicrovia technology, where anti-padsare largely eliminated. Worst Via-in-pad designOptimising anti-pad design 0V plane layer2Another issue with dense boards is Fig. 12: Connecting devices to planesthat anti-pads should not merge withone another, otherwise these can Embedded capacitancecreate a larger opening that obvi-ously hinders free flow of return 1. Signal tracescurrents and ruins the performance 2. 0V planeof the plane. In such cases, anti-pads’dimensions and placement must PCB center-linebe such that there is a web of 0V 3. Power planebetween these. 4. Signal tracesConnection of devices to planes Fig. 13: Microstrip configurationHigh contact impedance caused by the noisy component, which serves and to reduce ground noise.improper connections of devices to as an image plane terminating the 3. High-speed signals should0V or power planes can be enough radiated fields.to compromise the low impedance be routed on buried layers locatedbenefits gained by using planes If the ICs are located near the between planes. In this way, thefor 0V and power. Low inductance edge of the PCB, 0V plane will be planes can act as shields andcan be ensured by the following only on one side of the IC and the contain the radiation from high-considerations: fields can radiate from the other side. speed traces. Hence, noisy ICs and crystals should 1. Reducing the length and in- never be located on the edge of the 4. Multiple ground planes arecreasing width of the traces between PCB. As a general rule of thumb, very advantageous, since these willpads and via connecting the compo- ICs carrying digital signals with rise lower the ground (reference plane)nent to 0V plane. The best way is to time of two nanoseconds or analogue impedance of the board and reduceeliminate such traces altogether by components with frequencies more common-mode radiation.using via-in-pad design. than 200MHz, should have an unbro- ken plane that extends at least 5mm All the above objectives can be 2. Reducing the spacing between beyond its periphery. met if one uses an eight-layer board.the 0V plane and the component, On four- and six-layer boards, objec-which will reduce the length of the Layer stacking in boards tives 2 and 3 are not achievable andvia connecting the component to the a compromise has to be reached,plane, thus reducing via inductance. Layer stackup in a PCB is an impor- although multiple ground planes can tant factor in determining the EMC be provided on a six-layer board, at 3. Keeping vias carrying opposite performance of a product. While the expense of a signal layer.currents as close to each other as deciding the order in which variouspossible to maximise their mutual layers are stacked, following objec- Board stacking for four-layerinductance. tives must be kept in mind: boards. There are two conflicting considerations while deciding boardPosition of devices 1. A signal layer should always stacking of four-layer boards. First is be adjacent to a plane and be tightly the separation between power andDigital ICs and crystals are known to coupled (close) to it. This reduces ground planes. The lower the sepa-generate intense near-fields in their the loop area enclosed by forward ration, the higher is the decouplingimmediate vicinity that can radi- and return signals. capacitance, which can reduce theate, causing common-mode noise problem of supply transients and thegeneration and coupling to nearby 2. Power and ground planes associated generation of EMI.traces. This spread can be reduced should be closely coupled togetherby using an unbroken ground plane to maximise decoupling capacitance Second is the location of signalon the immediate bottom layer of traces. Keeping power and ground50 August 2016 | ElEctronics For You www.EFYmAg.com