Power Line Communication

A PROJECT REPORT ON

AC POWER LINE CARRIER COMMUNICATION BY Dinesh Auti Nikhil Asawadekar Rohan Shroff Rohankumar Samal Under the guidance of Prof. Sachin Charbhe

Submitted as a partial fulfillment of

B.E.(Semester VIII), Electronics Engineering From

RIZVI COLLEGE OF ENGINEERING BANDRA(W), MUMBAI - 400 050. UNIVERSITY OF MUMBAI. FOR THE ACADEMIC YEAR 2011-2012.

CERTIFICATE This to certify that the project report certified “AC POWER LINE CARRIER COMMUNICATION” Submitted by Dinesh Auti Nikhil Asawadekar Rohan Shroff Rohankumar Samal of Rizvi College of Engineering Electronics Branch has been approved in partial fulfillment of requirement for the degree of Bachelor of Engineering.

Prof. Sachin Charbhe Internal Guide

Prof. Nargis Shaikh (Head of the Department)

Dr. Varsha Shah (Principal)

Internal Examiner

External Examiner

ACKNOWLEDGEMENT It is with great pleasure that we are submitting this report on “POWER LINE CARRIER COMMUNICATION”. As in case project, we faced many problems while giving shape to our ideas and making the project mold into reality. We take this opportunity to express our sense of gratitude towards our internal guide Prof. Sachin Charbhe for his valuable suggestions and guidance from time to time. We have received constant support from Principal Prof. Varsha Shah, who has always encouraged us to be innovative in our approach. We are also thankful to the head of department, Prof. Nargis Shaikh and the remaining staff for making facilities available and giving their support and guidance. We express our sincere thanks to Prof. Ramkumar Maurya and Prof. Amit Redkar for their apt advices and their valuable time that helped our project gain the desired form and bring our ideas to reality. Guidance from Executive Engineer S.S.Lokare (MSEB, Airoli) and Bhargav Thakkar (Technical Head at ABB Corporation) added to our conceptual understanding of PLC systems. Although we have not mentioned each name, we would like to say that we appreciate every individual who was associated with our project and made experience satisfying and fulfilling one.

iii

ABSTRACT

Our project aims at introducing an old technology in a new way. As an alternative to existing communication systems. Traditional Power Line Communication (PLC) is widely used to provide real-time communications for protection of high voltage transmission lines. PLC is often the most economical and reliable high-speed dedicated channel available for protective relaying. PLC system is mainly used for managing the high voltage link and for communications between different substations. Our project PLCC, Power Line Carrier Communication, is an approach to utilize the existing power lines in the house or office for the transmission of information. Every house and building has

properly installed electricity lines. By using the existing AC

power lines as a medium to transfer the information, it becomes easy to connect the houses with a high speed network access point without installing new wiring. A power line carrier system includes three basic elements: a transmission line, presenting a channel for the transmission of carrier signal between two communicating nodes. Transformers and coupling equipment, providing a means of connection to the highvoltage transmission line and to provide electrical isolation between power line and circuitry. Transmitters and receivers circuitry . The simplified functional diagram of a power line carrier system is shown and explained further in the report.

iv

List Of Figures

Name Of Figure

Page No.

Illustration No.

PLC Modem

7

1

PLC Modem Circuit

7

2

Block Diagram of PLCC

9

3

RGB VI Block Diagram

13

4

4RGB Front Panel

13

5

Hamming Code Encoder

14

6

G Matrix

15

7

G Matrix Front Panel

16

8

Hamming Code Encoder Output

16

9

XR 2206 Modulator

18

10

FSK Modulator Board Layout

18

11

Modulator Output (f1)

19

12

Modulator Output (f2)

19

13

Basic Coupling Circuit

20

14

Coupling Circuitry

21

15

Output (L=75%)

22

16

Output (L=25%)

22

17

Measuring Impedance Of Power Line

23

18

Impedance vs Frequency

24

19

Attenuation Measurement

24

20

Attenuation Survey

25

21

FSK Demodulator Schematics

29

22

FSK Demodulator Board Layout

29

23

Syndrome Matrix

32

24

Decoding Process

33

25

Parity Matrix

34

27

v

Parity Check Matrix

35

28

P and HT Matrix

35

29

Possible Error Patterns

36

30

Hamming Decoder

36

31

Original Message

37

32

Corrected Output

37

33

Transmitter Side

38

34

No Transmission Error

38

35

Single Bit Transmission Error

39

36

Two Bit Transmission Error

39

37

Multi Bit Transmission Error

39

38

vi

List Of Tables

Table

Page No.

Table No.

PLCC & Comparison

5

1

Syndrome Table

33

2

Modulator Components

43

3

Demodulator Components

44

4

Miscellaneous

44

5

vii

List Of Symbols & Abbreviations

Symbol

Description

k

Message bits

q

Check Bits

n

Code Word Length

M

Message Vector

HT

Parity Check Matrix

X

Code Vector

Y

Output Vector

G

Generator Matrix

S

Syndrome Vector

E

Error Vector

C

Check Bits Vector

RC

Code Rate

IK

(Identity Matrix) K * K

P

Parity Matrix

SIndex

Syndrome Index

CENELEC

European Electro Technical Standards Committee

PLC

Power Line Communication

PLCC

Power Line Carrier Communication

PLL

Phase Locked Loop

BPS

Bits Per Seconds

ULP

User Language Program

viii

Table of Contents Acknowledgements........................................................................................................iii Abstract.........................................................................................................................iv List of figures.................................................................................................................v List of tables.................................................................................................................vii List of Symbols and abbreviations..............................................................................viii 1. Introduction............................................................................................................1 2. Literature Survey....................................................................................................2 2.1 PLCC Paper Analysis.......................................................................................2 2.2 Site Survey........................................................................................................4 3. Market Study.......................................................................................................... 5 3.1 Need According to Customer Point of View................................................... 5 3.1.1 Advantages Over Other Communication Systems............................6 3.2 Product Analysis & Study.................................................................................7 4. Block Diagram .........................................................................................................9 4.1 Block Description.............................................................................................10 5. Circuit Explanation................................................................................................12 5.1 Random bits generator......................................................................................12 5.2 Hamming Block Decoder.................................................................................14 5.3 Modulators........................................................................................................17 5.4 Coupling Circuitry............................................................................................20 5.5 Power line Characteristics................................................................................23 5.6 Receiver Side Coupling....................................................................................26 5.7 Demodulator.....................................................................................................27 5.8 Hamming Decoder............................................................................................30 6. Tools Used................................................................................................................40 6.1 Softwares used................................................................................................40 6.2 Hardware used................................................................................................44 7. Conclusion...............................................................................................................48 8. PLM v1.0 …............................................................................................................49 9. Applications............................................................................................................50 10. Future Scope.........................................................................................................53 11. References..............................................................................................................54 Index..............................................................................................................................55

Chapter 1

Introduction

1. Introduction Data Transmission in the twentieth century mainly meant the transmission of telephonic data over the wires. This had many disadvantages. Telephonic Equipment is comparatively costlier. Telephone Circuits were often unreliable. Telephone Lines were found to be unable to sustain the harsh weather conditions in the mountainous terrain and the extreme weather. In addition the electrical interference between the parallel power lines and the telephone lines was a case of concern. On the flip side the power Lines were much more robust and reliable. Since power Lines were already available it made much more sense to use them rather than investing in the making of new lines. Power Lines Communication gained a lot of ground in the early twentieth century. The advantages that were offered by the implementations of this technology and its social and economic impacts led to many companies investing in this technology and using it in their own grid. These Companies (GE, WestingHouse and much later AT&T) pioneered the development of this technology. Today Data Transmission through Power Lines has covered a lot of ground from its inception. It is available at a much lower cost and in a much compact design.

1

Chapter 2

Literature Survey

2. Literature Survey 2.1 PLCC Paper Analysis “ A Power Line Communication Tutorial - Challenges and Technologies ” The Power Lines available today were built for the purpose of power transmission from one place to another. The attempt to transmit data over these power lines leads to the reception of a lot of noise. This noise is due to the numerous devices connected to the power lines. An analysis of this noise and their characteristics helps us better understand how to tackle the problem of noise elimination in the Power Lines. The characteristics of the modulation techniques and their subsequent analysis gives us an idea of the advantages and disadvantages of each technique. The receiver contains a phase locked loop. We studied the modulation techniques and compared their performance in the present of noise. Finally Spread Spectrum technology is reviewed for the use of communications on Power Lines. Spread Spectrum is a method of signal modulation where the transmitted signal occupies a bandwidth considerably higher than the minimum necessary to send the information and some function other than the information being sent is used to increase this Bandwidth. Spread Spectrum was found to be unsuitable and rather detrimental for the PLCC system. Inference : After carefully studying the various technology we infer that Digital Signal Processing is absolutely necessary for the system to function efficiently. Spread Spectrum is found to be having a negative impact on the output and hence should be avoided. FSK is found to be the most immune to noise and hence chosen for our project.

2

Chapter 2 Literature Survey

“ Design Of Domestic Power Line Communication ” This report discusses the power-line communication over the low-voltage grid, which has A very high potential growth in the near future. The main advantage with power-line communication is the use of an existing infrastructure. Wires exist to every household connected to the power-line network. This report starts with a general introduction to power line communication. Then it discusses the application of an existing home automation system, then communicating over a low-voltage grid is investigated in order to obtain some knowledge of how the power line acts as a communication channel. The power-line communication channel can in general be modeled as a system with frequency dependent signal-to-noise ratio varying with time over the communication bandwidth. Finally we describe the basic parts of the system that eventually could be used for information transfer over the power-line communication channel.

3

Chapter 2 Literature Survey

2.2 Site Survey The best way to study any technology is to take guidance from the people who are working in similar field. We came to know that Maharashtra State Electricity Board (MSEB) and ABB Corporation are the two giants in the industry who use similar technology. So our first step was to take help of technical experts working there in order to tackle problems we are going to face. We went to MSEB (Airoli) where Executive Engineer S.S.Lokare Sir helped us a lot to make us aware of how PLCC actually works. He gave us examples of different substations situated near Navi-Mumbai & Mumbai area and explained us how actually power flows from one sub-station to another via gantries and also how the main station situated at Airoli controls everything. He also explained us how voice data travels through the power line and showed us technical aspects of the same. He backed us for our project and ensured that digital data can be made to flow over power line. By using modulation techniques. When we started struggling with coupling and isolation related problems we visited ABB Corporation to take some help. We had surfed on the net that ABB works with PLCC Technology. A visit to ABB was indeed of lot of help and support. Technical Head at ABB Mr. Bhargav Thakkar helped us explaining how PLC Systems work on broader context. He told us that for coupling purpose Current Voltage Transformer (CVT) which costs in lakhs and is used to block the AC Power signal coming into the transmitter/receiver system. Also we came to that Line Matching Unit (LMU) is used in PLCC which is used to match the impedance of input and output circuitry and building prototype for it is not possible. But he also ensured that for general prototype as a final year project a coupling circuitry can be used instead. which consist of capacitors and inductors. This really boosted our confidence and we started working accordingly.

4

Chapter 3

Market Study

3. Market Study 3.1 Need According to Customers Point of View PLCC system in the market will have to compete against telephone and intercom systems. PLCC system has the potential to outperform telephone and intercom systems. As these systems require additional resources and installations. Which incur a lot of setup cost. Plus the additional wiring makes system bulky and unportable. Whereas a power line system does not incur any setup cost has no additional wiring and can perform rather more efficiently than the conventional telephone and intercom systems. With the help of PLCC system one can transmit and receive data as well as voice signals. PLCC is a plug and play kind of system which can be plugged into any electric socket and communication can be established within a same building or nearby areas. The customers will be required to buy a PLCC system adapters which is a one time cost and can be used for lifetime. Also the size of adapters is small which makes it easily portable unlike telephone or intercom. So the user can take these adapters to a new place or new office and the system is established within no time. All the user has to do is to plug the adapters in sockets in the rooms he/she wants. Considering the above stated merits PLCC system is certainly the best fit in today’s modern age. PLCC systems completely fit the need of the customers as it eliminates the shortcomings of the conventional system. Now the only concern according to customer point of view is the cost factor. Lets see the cost wise analysis of PLCC system with telephone and intercom.

Intercom

Telephone

PLCC

Cost/unit( in Rs)

1650

500 + service tax* + installation charges + monthly rental

1350

Cost after one year/unit(in Rs.)

1650

12 X (service tax* + monthly rental)

1350

5

Chapter 3 Market Study

3.1.1 Advantages Over Other Communication Techniques PLCC uses existing power line for communication so it provides many advantages over traditionally used telephone models and other communication systems. The main advantage of power line carrier communication is cost on infrastructure is reduced to a large extent. Consider any building or company office as an example. To supply electricity for the whole structure first Mains cables are dropped throughout the building and it bears all the load thruster by fridge , fans and all the other equipments or devices run on electricity. If PLCC modem is used in such an area , no additional wiring or cabling is required as PLCC uses this power line only. Data is sent on this with equipotential coupling circuitry using modulator and it's retrieved at the receiver's side using demodulator. Thus elimination of wiring or cabling is the biggest bliss in communication system. This is also a flexible type of service which can have different formulations as per the need or application. Half duplex PLCC or Full Duplex PLCC modems are available. Thus they are now greatly used in houses and small office networks. It is also considered asx a replacement to intercom as it doesn't need any extra cabling.The biggest relief to the customers is when you talk about installation charges and service tax. Apart from initial installation charges , user doesn't need to pay service tax and government taxes for it as he's using existing power line only for communication. With built-in Error Checking and direct interface with uc as an ad-on , it's the biggest source of Research and Development since last 50 years. With other applications like Automatic meter reading , Fire & Security Alarm Systems and Lighting Control this serves as the major Integration for all the tasks that can be computed easily. With the invention of new modems such as PLC Modem from Sunrom Technologies , care has been taken that though using a same platform for transmitter and receiver side , high power side and low power side are isolated so chances of shock hazards are reduced to large extent and device is made more user friendly.

6


3.2 Product Analysis The successive step in study of PLCC is to have a glance on devices which are using this technology. Technical Experts from ABB Corp and MSEB suggested us two such devices mentioned below.

Illustration 1: PLC Modem This device which supports Windows XP/Pro , Linux OS is like a home plug adapter in the power line network for signal transmission, to achieve any power outlet next to Internet . With data rate 200Mbps and working temperature range -20 to -60 degrees , this serves as easy to connect, easy to use, plug and play device for home and small office networking environment.

Illustration 2: PLC Modem Circuit The above device has built-in on board AC isolated coupling circuit, which allows direct and simple connections to mains. Due to isolation on AC part, there is no worry to get

7


shock on the low voltage side when working with it. So it's user friendly device. It has high immunity to electrical noise persistence in the power line and built in error checking so it never gives out corrupt data. It transmits and receives serial data at 9600 bps. Transmission is based on byte by byte basis. Once you give one byte to module for transmission, you will have to wait at least 500ms before a new byte is given to module again since the module waits for zero crossing of AC mains to transfer a bit. For AC 50Hz system the zero crossing of AC signals happens every 10ms and modem needs 50 zero crossings to transmit one byte with error checking data. That is why it takes 500ms for one byte. As a half duplex system it normally operates in Receiver mode , once your application gives serial data to transmit on its RX-IN pin, it switches over to transmit and transmits the data through power line. Due to low cost , built in error checking, it's mainly used for Home Automation and Process Control.

8

Chapter 4

Block Diagram & Description

4. Block Diagram & Description 4.1 Block Diagram

Illustration 3: Block Diagram Of PLCC

9

Chapter 4 Block Diagram & Description

4.2 Block Diagram Description This block diagram explanation will give the basic idea about the flow of data from one user to another. It will give the general idea about the processing that the data underwent from one section to another. Following is the end to end jest of the project. We first generated a sequence of random bits with the use of Labview. This will act as the data given by the user which is to be transmitted to the receiver. Random bits are generated for illustration purpose. Random bits generator can generate bits form 4 bit to as many bits desired. These random bits which is considered as data cannot be directly sent over the power line because the data is bound to introduce an error due to noise present on the power line. Noise on the line cannot be curbed but the error introduced can be detected and corrected. For that Hamming codes are used which is capable of detecting multiple errors but can correct multiple errors. In hamming code check bits are appended at the end which will help the receiver to correct the error if any. Now we have a bit stream of data and check bits. We need an interfacing device will will help us interface the labview which is on the computer with the FSK modulator. That job is done by arduino. Arduino takes the bit stream from the computer and generates the same bit stream from one of its output pin. This stream of bits is now given to FSK modulator which will convert the digital data to analog form so that it can be sent over a power line. This is done because if digital data is sent over any channel then it will consume lot of bandwidth and the signal will also get corrupted very easily. FSK modulator converts logic 1 to sine wave of 2200Hz and logic 0 to sine wave of 1200Hz We have used XR 2206 as our FSK modulator. Now our information in in the frequency of the sine wave. Noise on any channel affects frequency the least. So our data is safe But the power line is of high voltage so care has to be taken so that the high voltage does not enter the transmitter circuitry. For that coupling is done .Coupling provides the necessary isolation between low and high voltage.

10

Chapter 4 Block Diagram & Description

The functioning of the receiver side blocks is the exact opposite as that of transmitter side. The coupling circuitry on the receiver side not just provides the isolation but also acts as a tuned circuit will allows only the high frequency in a selected band i.e. between 800Hz to 3000Hz to enter the receiver side. The FSK demodulator doe the exact opposite of FSK modulator. It decodes the two frequencies into respective 1's and 0's. We have used XR 2211 as or FSK demodulator. For the FSk demodulator to detect the input signal it should be greater than 10mV. But not exceeding 3Vrms. Arduino is used for interfacing the demodulator with the labview. The hamming decoder in Labview will detect and correct error if any. by using the check bits. The hamming decoder can detect multiple errors but correct only single bit errors. After the corrected code word is received the decoder will remove the check bits so that the original data transmitted is extracted from codeword and displayed.

11

Chapter 5

Circuit Explanation

5. Circuit Explanation The PLCC system has been shown in the form of a block diagram representation in illustration 3. The description below provides a flow of data from its origin to its destination. Each block will be explained but importance will be given to its implementation in the system above. First, let's take a look at the origin of data i.e. possible sources of data and the form in which the data is available. The input to the above system will be in the form of one's & zero's, so the analog counterpart needs to be converted to its appropriate digital equivalent via suitable methods (not listed in the block diagram). While doing so care has to taken that the baud rate must remain appropriate so as to not violate the modulators design constraints. Before starting it is assumed that the data at the input of the system is digital. Also the code provided is graphical & is simulated in LabVIEW development environment. Following is the block by block introduction to the system. 5.1 Random Bits Generator (RBG) It is purely for simulation purposes that instead of giving any particular data, a random bits stream is applied at the input of the system. It is based on the principle of Bernoulli's noise. It generates a pseudo random sequence of one's & zero's depending on the probability p, which is given as a input. For example if p=0.7 then there is a 70% probability that the outcome of the Bernoulli's noise generator is 1. P(X = i) = pi(1 – p)^(1 – i) (i = 0, 1)

Bernoulli noise is a special case of Binomial noise.

12

Chapter 5 Circuit Explanation

We will make a RBG in LabVIEW with the Bernoulli's noise VI (Virtual Instrument) found in the Signal processing Toolkit. Below is the snapshot of the RBG.

Illustration 4: RBG VI Block Diagram The input to the Bernoulli's noise VI is the number of samples, which has a default value of 128. The value of p is 0.5 (not shown). At the output a not equal to block is used to convert the output of Bernoulli's noise to one's & zero's.

Illustration 5: RBG Front Panel

This the output snapshot of Bernoulli's noise showing a random bits pattern in binary format. Now the output from the RBG is given to an Hamming coder, which will provide the required noise immunity to our data. This is called as channel coding.

13


5.2 Hamming Block Encoder Hamming code is a type of linear block code. A block of data has 'k' message bits and 'q' check bits. A random bits stream enters the hamming block encoder and output is data packets each of size 'k+q'. This 'k+q' is denoted by 'n' and is called the block size. Where, n = 2q - 1 ;

n>q

k=n-q These codes have d min = 3, which means that they can detect up to two errors or correct one single error. For example, if k=4 & q=3 then n =7. This represents a (7,4) hamming code [6]. Code rate : It is defined as message length divided by code word length. Code Rate = Rc = k/n ; Higher the code rate is better and becomes more efficient M = message vector = ( m1, m2, m3,....)1xk C = check bits vector = ( c1, c2, c3,.......)1xq X = Code vector = (M | C)1xn

Illustration 6: Hamming Code Encoder

14


The input is q & k , which is given to the G matrix generator to produce a G matrix. The G matrix is then multiplied to a message matrix M which gives the final code words matrix. Note that proper care is to taken for matrix multiplication [8]. Where, G = ( Ik | P)kxn Ik = Identity matrix (kxk) P = Parity matrix The P matrix introduced here consists of q bit words with hamming weight at least 2, arranged in any order. X = MG Below is the code for G matrix

Illustration 7: G Matrix

The inputs to the G matrix is k & n. Below is the output with k =4 & q = 3. Readers should note the 4x4 identity matrix. The first four coloums consist of an 4x4 identity matrix and remaining three coloums consists of two or more one's as stated before.

15


Illustration 8: G matrix Front Panel

Consider any one of the sixteen 4 bit messages Let's say M = (0110). Then for values of k = 4 & q = 3, we get the following code word as shown in the snapshot below.

Illustration 9: Hamming Code Encoder Output The important thing to note here is that the matrix multiplication between M & G is a modulo 2 multiplication.

16


5.3 Modulator Let’s consider the Modulator. Modulation is the technique of forwarding low frequency baseband signal to high frequency bandpass signal. The need of modulation here is to mainly transform digital signal into equivalent analog signal using a form of modulation known as Frequency Shift Keying (FSK). XR-2206 is a function generator IC which can produce stabilized modulated FSK waveforms at frequencies ranging from 0.01 Hz to 1MHz.The XR-2206 is comprised of four functional blocks; a voltage-controlled oscillator (VCO), an analog multiplier and sine-shaper; a unity gain buffer amplifier; and a set of current switches. It offers output impedance in the range 600Ω + 10% . The Mark and Space frequencies can be independently set by the choice of timing resistors R1 and R2 respectively and the capacitor C0. So depending upon our requirement we can select proper values of design variables [2]. C0 is chosen as 0.1uf and from this we have evaluated the values needed for Mark and Space frequencies i.e R1 = 8.333KΩ and R2 = 4.545KΩ

17


Below is a schematic of the XR2206 Modulator from Exar.

Illustration 10: XR2206 Modulator

The PCB Layout of the above modulator schematic is shown below.

Illustration 11: FSK Modulator Board Layout

18


Output of the Modulator :

Following are the screen-shots of the DSO which was connected at the output of the modulator.

Illustration12: Modulator output (f1)

Illustration 13: Modulator Output (f2)

19


5.4 Coupling Circuitry A coupling circuit is used to connect the communication system to the power-line. The purpose of the coupling circuits is two-fold. Firstly, it prevents the 50 Hz signal, used for power distribution, to enter the equipment. Secondly, it certifies that the receiver/transmitter circuit is tuned to work in a particular band of frequency. This increases the efficiency of the receiver and makes sure that the receiver does not detect any unwanted signal. The transformer in the coupling circuitry provides the necessary impedance matching as well. The output of modulator which is a high frequency bandpass signal is fed to the coupling circuitry which consist of transistor 2N2222 which acts as a valve that allows only the high frequency modulated signal from the modulator to reach the power line and block the 50Hz from entering the modulator circuitry. The coupling circuit also incorporates a tank circuit which has a precharge capacitor so that the oscillation amplitude remains steady. The frequency output of the tank circuit can be tuned to a desired one by varying the inductor value of the slug-tuned IF(Intermediate frequency ) transformer. The output frequency value depends upon the inductor and capacitor value. The capacitors in series helps to attenuate the 50Hz signal and allow high frequency from the tank circuit to pass through retaining its full strength [1].

Illustration 14: Basic Coupling Circuit

20


The circuit shown in illustration14 is explained above. The illustration below is a snapshot of the simulation the coupling circuit. Illustration13 & 14 are the outputs of this circuit for different values of inductor. The voltages and current at various nodes are shown in the figure below.

Illustration 15: Coupling circuitry

21


Illustration 16 shows the condition when the value of the inductor is set to approximately 75% of its value. The attenuation of the sine wave for this value is negligible.

Illustration 16: Output (L = 75%) Illustration 17 shows the condition when the value of the inductor is set to approximately 25% of its value. The attenuation of the sine wave for this value is considerably satisfactory.

Illustration 17: Output (L = 25%)

22


5.5 Power Line Characteristics Impedance and attenuation measurements are performed on the loaded power lines into three categories: rural, urban and the industrial power lines. Impedance of the power lines looked at a wall receptacle in research building is measured by the circuit shown in illustration 18. The frequency range of measurement is selected between 10 kHz and 150 kHz because these frequencies belong to the CENELEC bands. The measurements system is described in illustration 18. A signal generator (SG) is used to simulate PLC carrier signal and an AC millivoltmeter is used to measure the values of voltages: V1, V2 and V3 are shown in the circuit diagram. In the circuit, a coupling transformer T, and the coupling capacitor C , are added to the measurements system because of this component should be used on the PLC. Every modem must consist a coupling transformer and a coupling capacitor to send or receive carrier from or to power lines. So, T and C are necessary elements on the power line communications.

Illustration 18: Measuring Impedance of Power Line Power line impedance is a very important parameter on the design of power line communications modem architecture. Variations on the impedance of the power line affect the communications circuit performance. In order to determine impedance of the power lines, measurements were carried out in Turkey at frequencies ranging from 10 to 170 kHz . Measurements were conducted in three categories: rural, urban and the industrial power lines. The measured impedances were determined as 4-21 ohms for urban. Here is a resonance and a local max at 60 kHz for urban power lines and impedance of 4 to 12 ohms at 60-80 kHz bands at the urban power lines. After 80KHz the impedance increases. 23


Illustration 19: Impedance vs Frequency

Attenuation measurements are made using the hardware layout shown in illustration 20. Two transceiver modems are used, one of them is a transmitter, the other one is the receiver. T1 and C are the coupling transformer and coupling capacitor on the transmitter modem and the others T2 and C are the same components on the receiver side. An AC millivoltmeter is used to measure V1 and V2 voltages in order to calculate signal attenuations on the along the power lines. Experiments on signal attenuations of the power line are realized at different parts of homes. The parameters of the signal attenuation measurements are line length, carrier frequency, the numbers of connector box. The conductors of phase-neutral, phase-ground and neutral-ground may be used as the communication channels. Normally phase-neutral conductors are used as PLC channel, but in this study other ground conductor also observed. The reason of the selection different channel ways is to examine the characteristics of the possible channels in the PLC[7].

24


Illustration 20: Attenuation Measurement Phase-neutral power line channel in rural area has more attenuation with respect to other phase- ground channels and neutral-ground channels up to frequencies 120 kHz, is shown in illustration 21. Attenuation measurements in rural power lines are carried out at the different plugs in the normally loaded homes. Selected homes are similar the each others with about 120 m2. Attenuations are observed between 4-19 dB. Urban homes are normally located at the city centers. Illustration 21 shows that power lines attenuations in the urban decrease versus frequency after 70 kHz. Attenuation value may raise up to 23 dB in urban areas. Attenuation measurements at the all the different PLC channels such as rural, urban and the industrial power lines are given in illustration 21 Measured o attenuation values at the industrial power lines are bigger than rural and urban due to heavy loads in this kind of power lines. These measurements are made inside homes between different plugs on the wall, so line length is small such as a few ten meters. These results may be used at the home automation modems via PLC.

Illustration 21: Attenuation Survey 25


5.6 Receiver Side Coupling Coupling at receiver side also performs the same job as that of transmitter side that to block high voltage 50Hz and allow low voltage, high frequency carrier signal to pass through. The circuitry and the role of the components in the circuit are exactly the same. A coupling circuit is used to connect the communication system to the power-line. The purpose of the coupling circuits is two-fold. Firstly, it prevents the 50 Hz signal, used for power distribution, to enter the equipment. Secondly, it certifies that the receiver/transmitter circuit is tuned to work in a particular band of frequency. This increases the efficiency of the receiver and makes sure that the receiver does not detect any unwanted signal. The transformer in the coupling circuitry provides the necessary impedance matching as well.

The output of modulator which is a high frequency bandpass signal is fed to the coupling circuitry which consist of transistor 2N2222 which acts as a valve that allows only the high frequency modulated signal from the modulator to reach the power line and block the 50Hz from entering the modulator circuitry. The coupling circuit also incorporates a tank circuit which has a precharge capacitor so that the oscillation amplitude remains steady. The frequency output of the tank circuit can be tuned to a desired one by varying the inductor value of the slug-tuned IF(Intermediate frequency ) transformer. The output frequency value depends upon the inductor and capacitor value. The capacitors in series helps to attenuate the 50Hz signal and allow high frequency from the tank circuit to pass through retaining its full strength.

26


Receiver Side : The receiver side starts with a coupling to the power line. This is essential because we need to separate low voltage circuit from high voltage power line. The coupling part explained in the above section. After the coupling we need step down transformer to step down the 230V voltage to 12V required by the receiver circuit to operate. Another main reason for the transformer is to isolate the low power circuit from the high power circuit. The low voltage step down signal is then passed to a tuned circuit, which will allow only a select band of frequencies to pass. Arrangement for the above explanation is shown in illustration 13. The signal that we get after the above step is then required to be demodulated and then decoded. The demodulation is done using XR2211 FSK DEMODULATOR from Exar Corporation. A hamming decoder is used to decode the message. Below is a block by block explanation of the receiver side. 5.7 Demodulator : The XR -2211 is a Phase Locked Loop (PLL) integrated circuit especially designed for data communication and particularly suited for FSK applications. It operates over a frequency range of 0.01 Hz to 300KHz and can accommodate analog input signals between 10mV(RMS) to 3V(RMS) [3]. Frequency shift keyed input signals fed into pin 2 of the XR-2211 must be capacitively coupled through a 0.1uf capacitor. The internal impedance is 20K and the minimum recommended input signal is 10mV. The first order of business is to set center frequency of the demodulator passband at the center of frequency band that we wish to detect. For showing a prototype we have chosen center frequency 1624 Hz. Mark frequency we have selected is 1200 Hz and space frequency is 2200 Hz. The center frequency of the two frequencies is 1624 Hz. The component values are computed as follows.

27


f0 = 1/(R0*C0). where R0 is 15.788K. The value of R0 is adjusted by using a 10K resistor and a variable pot for fine adjustment. The value of C0 is chosen as 39nf. R1 sets the system bandwidth and C1 states the loop filter time constant. and damping factor. The value of R1 is determined by Mark and Space frequencies . R1 = (R0*f0) / (f1-f2). The value of C1 is chosen approximately as C0/4. The Resistor Rb provides positive feedback across the fsk comparator and facilitates rapid transition between output logic states. Cf and Rf form a single pole post detection filter for FSK data output. Rf is most often set at 100K and Cf smooths the data output. Its value is roughly calculated [1]. Cf = 3/(Data Rate in Bits per second). Because this modem is designed for operation at 1200 BPS , a value of 2.2nf is acceptable.

28


The schematics of the XR2211 is show below.

Illustration22: FSK Demodulator Schematics

Illustration 23 is the board layout of Demodulator using XR2211.

Illustration 23: FSK Demodulator Board Layout

29


The output of the demodulator is in the form of ones & zeros. In order to read the values of the demodulator we need a micro controller, which would properly interpret the demodulators output so that it can be further processed & message can be decoded. 5.8 Hamming Decoder : As shown below the generator matrix is used to generate a Code word from message. If we use an ideal channel i.e. no transmission errors then the transmitted code word should be equal to the received code word. But in reality this may not be the case. There may be single bit or multiple bit errors. Errors are denoted by error vector E as shown below. Error vector is the list of all possible error patterns that can be introduced during transmission.

Message

M

G

Code Word

Y

X

Received Code Word

E Error Vector

We know that the G matrix is represented as an augmentation of identity matrix and a parity matrix as shown below G = ( Ik | P)kxn Ik = Identity matrix (kxk) P = Parity matrix

30


The corresponding equivalent in the decoder is the Parity Check Matrix H T . The parity check matrix is also a combination of an identity matrix and a parity matrix but they are stacked one below the other as shown below H T = ( P / I q )n x q One of the most important properties of the Parity Check Matrix H T is that modulo 2 multiplication of X and HT is always a zero vector. The only condition that is required to be fulfilled is that X should be a valid code word. Symbolically, ( HT )*( X ) = {0,0.........0} This becomes the basis for error detection. In simple words if X is not a valid codeword the product is going to be a non zero value. We next define a matrix called as Syndrome Matrix denoted by 'S' S = Y * ( HT ) Syndrome Vector is a 1/Q matrix. Y is a 1/N matrix and H is N/Q matrix. Consider Y = X+E E = Vector of error patterns X = Transmitted code word Substituting value of Y in above equation , we get S = (X+E) * ( HT ) S = X*( HT ) + E*( HT ) Note that addition in the above equation is Modulo2 addition.

31


From the above theory we know that X*( HT ) = 0. Therefore S = E*( HT )

Illustration 24: Syndrome Matrix Suppose S = (00....) , this has two possible interpretations. 1. There are no transmission errors in the received codeword. Thus E = 0. 2.

Occurrence of an undetectable transmission error that is Y appears to look like a valid codeword.

Whenever S is not equal to zero , we say that error has been detected. That error can be single bit error or multiple bit error. Hamming code is a type of block code in which we can detect up to two bit errors and correct upto one bit. Since our syndrome has q bits , there are 2q possible syndromes and 2n possible error patterns. For eg. In our case , q = 3 for a (7,4) hamming code. 23 = 8 Syndrome patterns and 27 = 128 Error patterns. Therefore we get 16 (128/8) , different errors produce the same syndrome. That is not all errors can be corrected. We adopt a procedure called as Maximum Likelihood Decoding wherein 1. 0 errors is most likely 2. Single bit error is next most likely. We need to associate each possible syndrome with its most likely error pattern. 32


Illustration 25: Decoding Process

In the above block diagram , we use the received codeword as the input in order to calculate 'S'. Then we use a notation called as Syndrome Index Si which is used to point to the suitable error pattern in the table of error pattern. The output of the table of error patterns is E^. This E^ is our best possible guess of the position where the error has occurred. Now we perform a modulo2 addition of E ^ and the received codeword Y to get the corrected code word X.

Syndrome (S)

Error pattern (E)

000

0000 000

001

0000 001

010

0000 010

011

0010 000

100

0000 100

101

0100 000

110

1000 000

111

0001 000

Above table illustrates the Syndrome tables and the corresponding Error vector values.

33


Thus using concept of syndrome and the possible error vector values we are able to correct the received code word which has up to single bit of error. Following is a graphical code snapshot of the Parity Check Matrix HT .

Illustration 26: Parity Check Matrix

As we can see in the illustration above we need the Parity Matrix as the input to generate the parity check matrix. Consider the Parity matrix shown below

Illustration 26: Parity Matrix

The parity matrix shown above consists of all the three bit values that contain one or more than one 1's.

34


The parity check matrix is a (n x q) matrix as shown below. It is represented as follows H T = ( P / I q )n x q

Illustration 28: Parity Check Matrix

Illustration 29: P and HT Matrix

35


List of all possible error patterns that can occur in a (7,4) hamming block code.

Illustration30: Possible Error patterns

Figure below shows the entire decoder in a graphical form.

Illustration 31: Hamming Decoder

36


Let's say that we send an encoded message shown in illustration 28 via the power line towards the receiver. The encoded message consists of a 4-bit message and a 3-bit check bit. Below is an example of M = 0110 011. Wherein, m = 0110 ; message bits (4) q = 011

; Check bits (3)

Illustration 32: Original Message

The message that has been encoded i.e. m = 0110 is one of the valid sixteen message words. Therefore if we assume a error free transmission then the output would look like as shown in illustration 29.

Illustration 33: Corrected Output

If a error occurs during transmission then there may be following cases : 1. Single bit error transmission 2. Two bit error transmission 3. Multi bit error transmission These cases are shown below

37


Transmitter side :

Illustration 34: Tx side The illustration 30 shows the front panel of the transmitter side. The encoded bits section shows the 7 bits that are to be transmitted serially out of the Power Line Communication Modem. The figure also shows a boolean representation of the 7 bits encoded message. The values of k, q and n are as shown in the illustration. The value of n that is the codeword size depends upon the no. of check bits that are required. In our case, it's k = 4 , q = 3 and n = 7. Receiver side : 1. No transmission error

Illustration 35: No transmission error 38


2. Single bit transmission error

Illustration 36: Single bit transmission error 3. Two bit transmission error

Illustration 37: Two bit transmission error

4. Multi bit transmission error

Illustration 38: Multi bit transmission error

39

Chapter 6

Tools Used

6. Tools Used 6.1 Softwares Used

1. NI LabVIEW

LabVIEW (short for Laboratory Virtual Instrumentation Engineering Workbench) is a platform and development environment for a visual programming language from National Instruments. The purpose of such programming is auto mating the usage of processing and measuring equipment in any laboratory setup. LabVIEW is a graphical programming environment used by engineers and scientists to develop sophisticated measurement, test, and control systems using intuitive graphical icons and wires that resemble a flowchart. It offers unrivaled integration with thousands of hardware devices and provides hundreds of built-in libraries for advanced analysis and data visualization – all for creating virtual instrumentation.

LabVIEW

40

Chapter 6 Tools Used

2. Eagle CAD

EAGLE provides quality PCB design software with the features that get the job done. For over 20 years, EAGLE has been satisfying design engineers around the world, by offering the same core functionality as expensive commercial software, at the fraction of the cost. Easy to learn •Schematic editor, layout editor, library editor modules with identical user interfaces •Free service support through dedicated experts •Compatible with Windows®, Linux®, Mac® Easy to buy •Purchase and license on-line or with personal support from our distributors •No maintenance fees or add on contracts Easy to use •Flexible User Language Programs (ULPs) enable custom features, such as individual instruction sequences, simulation, data export and import •Export Gerber files that can be used at any board house: •Gerber 274X & Gerber 274D •Excellon NC Drill Format •SM1000 and SM3000 •Custom user-defined export formats •Online import of product & pricing information through DesignLink •Active customer forums to share files, libraries ULPs, design tips and more •Parse and paste your data outside of EAGLE (XM datastructure)

41


3. Arduino

Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software. It's intended for artists, designers, hobbyists, and anyone interested in creating interactive objects or environments. Arduino can sense the environment by receiving input from a variety of sensors and can affect its surroundings by controlling lights, motors, and other actuators. The micro controller on the board is programmed using the Arduino programming language (based on Wiring) and the Arduino development environment (based on Processing). Arduino projects can be standalone or they can communicate with software running on a computer (e.g. Flash, Processing, MaxMSP).

Arduino UNO

Arduino IDE

42


4. MultiSim

NI Multisim (formerly MultiSIM) is an electronic schematic capture and simulation program which is part of a suite of circuit design programs, along with NI Ultiboard. Multisim is one of the few circuit design programs to employ the original Berkeley SPICE based software simulation. Multisim was originally created by a company named Electronics Workbench, which is now a division of National Instruments. Multisim includes microcontroller simulation (formerly known as MultiMCU), as well as integrated import and export features to the Printed Circuit Boardlayout software in the suite, NI Ultiboard.

43


6.2 Hardware Used Modulator Components

Part

Value

Package

C

10uF

C2

Position (inch)

Orientation

CPOL-R AD SparkFun

(1.6.0.65)

R180

10uF

CPOL-R AD SparkFun

(2.05 1.75)

R0

C3

1uF

CPOL-R AD SparkFun

(0.75 1.6)

R90

C4

M01PTH_L

CPOL-R AD SparkFun

(0.85 0.75)

R0

FSKIN

M01PTH_L

1X01_L

SparkFun

(2.35 1.05)

R90

FSKOUT

M01PTH_L

1X01_L

SparkFun

(1.1 0.35)

R0

Ground

M01PTH_L

1X01_L

SparkFun

(2.35 1.45)

R90

Ground 1

M01PTH_L

1X01_L

SparkFun

(0.5 0.35)

R0

1X01_LS

SparkFun

(0.3 1.65)

R90

JP1

Library

R3

200

AXIAL_0.5

SparkFun

(1.4 1.6)

R0

R4

5.1K

AXIAL_0.5

SparkFun

(1.8 2.1)

R0

R5

5.1K

AXIAL_0.5

SparkFun

(1.3 1.9)

R0

U$1

TRIM_POT

SparkFun

(2.05 0.35)

R90

U$2

TRIM_POT

SparkFun

(0.55 1.15)

R180

U$3

TRIM_POT

SparkFun

(2.35 0.75)

R180

DIL16

SparkFun

(1.55 1.15)

R0

u1

XR2206

Total Cost = Rs. 200

44


Demodulator Components

Part

Value

Package

C

0.1uF

C0

Position (Inch)

Orientation

CPOL_RAD SparkFun

(1.1 1.9)

R90

27nF

CPOL_RAD SparkFun

(2 1.8)

R90

C1

2.7nF

CPOL_RAD SparkFun

(2.2 0.4)

R0

C2

0.1uF

CPOL_RAD SparkFun

(1 1.6)

R0

C4

0.1uF

CPOL_RAD SparkFun

(2.6 1.6)

R270

CF

1nF

CPOL_RAD SparkFun

(2.8 1.3)

R270

DATAOUT

MO1PTH_L 1x01_L

SparkFun

(0.8 0.5)

R0

FSKIN

MO1PTH_L 1x01_L

SparkFun

(0.4 0.8)

R90

GND

MO1PTH_L 1x01_L

SparkFun

(1.2 0.5)

R0

GND2

MO1PTH_L 1x01_L

SparkFun

(0.4 1.3)

R0

DIL14

SparkFun

(1.55 1.5)

R270

IC1

Library

R0

5K 1%

AXIAL-0.5

SparkFun

(2.3 1.5)

R90

R1

35.2K 1%

AXIAL-0.5

SparkFun

(2 1.1)

R270

RB

510K

AXIAL-0.5

SparkFun

(1.5 0.8)

R0

AXIAL-0.5

SparkFun

(2.5 0.9)

R180

RF RL

5.1K 1%

AXIAL-0.5

SparkFun

(0.7 1.6)

R90

RX

20K

TRIM_POT

SparkFun

(1.5 0.5)

R0

1X02_L

SparkFun

(2 2.2)

R0

SUPPLY

Total Cost = Rs.210

45


Miscellaneous components

Product Name

Product Quantity

Price per piece

Total(Rs.)

IC HOLDER

2

5

10

Jumpers

2 packs

10 (per pack)

20

Epoxy PCB

1

125

125

Dotted PCB

3

30

90

Transformer

2

35

70

Bug Strip

1

10

10

Total Cost = Rs. 155

46


Modulator & Demodulator

Modulator & Arduino

47

Chapter 7

Conclusion

7. Conclusion The project has the capability of transforming the information highway in India. In a way that India has bypassed the land-line telephone revolution, the adaptation of PLCC can help propel India into an elite group of countries with a very deep Internet penetration. This would in turn help in dispelling the superstitions and ignorance that prevails in some of the backward areas of the country. India’s image as a low cost development country in the world would get a major boost by the implementation of this technology on a wider scale. Power Lines Communication would result in a very large scale savings of the tax payers money. Efficiency of the existing infrastructure would be enhanced thus giving more value for money. It aims to ensure that the PLCC system can be used as a plug and play device without any major investments on the part of the consumer. PLCC is a technology that has the potential to revolutionize communication and to change the lives of the citizens if factors such as cost, effectiveness and security are carefully handled.

48

Chapter 8

PLM v1.0

8. PLM v1.0 Now as we have been through the practical and thesis sessions of this PLCC project , our next aim is how to get it in compact form. As it includes many advantages over other types of communication , it can be constructed or structured into compact form or portable form. And yes , to get a PLC modem in compact or portable form is possible. The duplex form of PLC is used now a days which allows the user to transmit and receive the data from the same platform. This is the biggest revolution in PLCC technology as far as communication over small houses , office networks and hub communication is concerned. SMD components are used to build the circuitry which reduces circuit size and weight of the product and thus restrictions over its portability can be eliminated. Built in board AC connection circuits with direct connection to AC mains and built in carrier generation technique can be used to reduce the external periferals which make the product bulky. At the same time by using LEDs for transmission and receiption , built in error checking can be implemented so correct data is guaranteed and it never gives corrupt data. Also High Power circuitry and Low Power circuitry can be isolated on same PCB thus serving both purposes less space, weight and hazard free device. AC isolated coupling circuit, allows direct and simple connections to mains. Due to isolation on AC part, there is no worry to get shock on the low voltage side when working with it. The total cost of the entire trans-receiver unit does not exceed Rs.1500. Thus an economical solution has been provided for data communication via PLCC modem by this project.

49

Chapter 9

Applications

9. Applications Power line networking offers several advantages over other available home networking technologies; the availability of power outlets in abundance in every home and offices , it eliminates the need of laying new wiring. PLCC technology can be deployed into different types of applications in order to provide economic networking solutions. Hence merging with other technologies it proves useful in different areas. These are few key areas where PLC communications are utilized: a. Transmission & Distribution Network: PLCC was first adopted in the electrical transmission and distribution system to transmit information at a fast rate. b. Home control and Automation: PLCC technology is used in home control and automation. This technology can reduce the resources as well as efforts for activities like power management, energy conservation, etc. Plug the adapter into any existing power sockets and you can program it to control other modules over your AC wiring. You can program all the switch modules in the house in a single unit and you can remotely switch lights, televisions, Audio-visual equipment and other appliances on and off with a touch of a button --- A handy controller for Home Automation. The Programmable Controller and the corresponding Switch Modules are configurable at the host station. An LCD screen shows the operating status of the modules under control. In modern homes, there is a huge requirement of sending digital information, audio, and video all over the home. Running new wires to support this will increase the burden and cost of maintenance. To overcome this, PLCC is the right choice to implement Home Automation concept. Home automation or also known as Smart Home technology is a collection of systems and devices in a home that have an ability to interact with each other or function individually in order to be optimized in best way. 50

Chapter 9 Applications

Using PLCC technology, existing power wiring of the house is used to connect home appliances with each other as well as with Internet. Architecture of a PLCC based home automation system is shown in the above image. Various home appliances are connected within a loop through the existing power cables. This technology can connect each device with the network which is connected to an AC outlet. All appliances are also connected with a centralized control panel which controls them. c. Entertainment: PLCC is used to distribute the multimedia content throughout the home. d. Telecommunication: Data transmission for different types of communications like telephonic communication, audio, video communication can be made with the use of PLCC technology. e. Security Systems: In monitoring houses or businesses through surveillance cameras, PLCC technology is far useful. The surveillance cameras connected over Power System in a light bulb is unique; simply screw it into any light socket. Hidden inside the "bulb" is a sophisticated Low-Light Monochrome Camera, coupled with PLCC circuitry. The video signal is "encoded" by this circuit and fed directly to the power line. Each Video Over Power System features a companion Decoder, which plugs into any wall outlet. A typical homeowner would plug in the decoder at the outlet nearest the TV. A standard video output connects the decoder to any TV or VCR using line-level RCA-type cables.

51

Chapter 9 Applications

Once the Decoder is plugged in and connected, live video is delivered to the TV or VCR. It's simple and easy. There are no wires to run, no holes to drill, and no antennas or complicated "tuning" is required. f. Automatic Meter Reading : Automatic Meter reading applications use the PLCC technology to send the data from home meters to Host Central Station. Automatic Meter Reading using PLCC technology is quite useful as it saves a lot of human efforts and also makes the whole system more efficient. The automatic meter reading system consists of three components, namely, Multifunction Node (MFN), Concentrator & Communication Node (CCN) and Operation & Management System (OMS). Different components and their inter-connections are shown in the figure. MFN is a unit installed in household meters, either incorporated in the meter itself or externally connected to it. Its function is to take reading of the meter on an hourly basis and store it in a memory chip. CNN is another part which manages all MFNs within a particular area and collects meter readings from all MFNs. It is generally installed on substations and needs a computer. The computer is installed with Operation and Management System (OMS) which further manages all the data and meter readings from CNNs.

52

Chapter 10

Future Scope

10. Future Scope a. Telecommunication: Data transmission for different types of communications like telephonic communication, audio, video communication can be made with the use of PLCC technology. The user will be free to choose the necessary mode of communication. b. Industrial Automation: In an industrial environment the PLC communication networks can be used to give electric energy related services, such as meter reading, demand management and remote billing but also to give value added services like remote control and security, automation or even, education, information and e business opportunities. On the other hand it can also offer telecommunication services such as traditional telephony and Internet. c. System protection: The communication link can be used to transit control signals that may be used to protect the system. For example, PLC can be successfully used in order to detect is landing operation of DER units. d. Telecommunication services: Current PLC networks are able to reach speeds of 200Mbps. Telephony and Internet services can be delivered at high speed through broadband PLC networks. Traditional telephony uses Plesiochronous Digital Hierarchy, PDH. PDH uses Time Division Multiplexing, TDM. One possibility is to send the TDM frame over IP, and the voice over TDM, VoTDM. However, this service should accomplish the quality and reliability criteria, like Bit Error Rate, timing and latency, and unfortunately the delay in VoTDM transmissions exceeds 25ms. Nevertheless, it is possible to give a good telephony service over IP. Over TCP/IP, VoIP and Internet services can be delivered at a 200Mbps speed, so it can be possible to compete with technologies such as ADSL.

53

Chapter 11

References

11. References [1] Ciarcia's Circuit Cellar, Volume 7 Build a Power-Line Carrier Current modem. [2] Designing Reliable Powerline Communications Published in EDN Ashish Garg and Angad Singh Gill, Cypress Semiconductor -- EDN, Dec 2, 2010 [3] Power Line Communication Modem Power Line Communication Modem Solutions from Texas Instruments [4] Data communication and networking - Behrouz A Forouzan. Hamming Code - page 280. [5] Measurements and attenuation for power line communication systems. [6] NI LabVIEW Getting Started [7] XR2206 Datasheet [8] XR2211 Datasheet

54

Index

Index A Arduino B Block description block diagram C coupling circuitry D Demodulator H Hamming block code hamming Decoder P Power line characteristics R Random Bits Generation M Modulator MultiSim N NI Labview

55

Power Line Communication

Recommend Documents