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CHAPTER 1
INTRODUCTION
The communication flow of today is very high. Many applications are operating at high speed and a fixed connection is often preferred. If the power utilities could supply communication over the power-line to the costumers it could make a tremendous breakthrough in communications. Every household would be connected at any time and services being provided at real-time. Using the power-line as a communication medium could also be a cost-effective way compared to other systems because it uses an existing infrastructure, wires exists to every household connected to the power-line network.
The deregulated market has forced the power utilities to explore new markets to find new business opportunities, which have increased the research in power-line communications the last decade. The research has initially been focused on providing services related to power distribution such as load control, meter reading, tariff control, remote control and smart homes. These value-added services would open up new markets for the power utilities and hence increase the profit. The moderate demands of these applications make it easier to obtain reliable communication. Firstly, the information bit rate is low; secondly, they do not require real-time performance.
1.1 AIM OF THE PROJECT
The main aim of the project is to design and develop a communication system in the real time using the power lines such that it can communicate with maximum efficiency.
This device is:
 Economical
 User friendly
 Reliable
1.2 LITERATURE SURVEY
Power line communication has been around for quite some time, but has only been used for narrow band tele-remote relay applications, public lighting and home automation.
* 1950: at a frequency of 10Hz, 10kW of power, one-way: town lighting, relay remote control.
* Mid 1980s: beginning of research into the use of the electrical grid to support data transmission, on bands between 5 – 500Khz, always in a one-way direction,
* 1997: first tests for bidirectional data signal transmission over the electrical supply network and the beginning of research by Ascom (Switzerland) and Norweb (U.K.)
Broadband over PLC only began at the end of the 1990s:
In the late 1990s, a number of companies from all over the world began serious research into exactly how to get high-speed signals across the network of electrical power lines. By 2004, the technology advanced to the point where hundreds of megabits per second could be transferred around the home - enough to carry multiple HDTV signals, whole-house audio, telephony, gaming, internet television, and dozens of other applications.
Making a connection is now as easy as finding the nearest power outlet.
The technology is known as Powerline communications or PLC. Groups like the Home Plug Powerline Alliance are now working to let the world know how easy it is to unlock the incredible bandwidth found in common already-installed power lines.
1.3 OVERVIEW OF THE PROJECT
The term communication can broadly be defined as a unilateral or bilateral or bilateral transfer of meaningful data between two points through a medium. The data to be transferred may be analog or digital in nature.
The transmission medium, which is used in Power line modem, is mains line that provides a very cheaper and easier means of communication. In this system we are transferring files from one computer to another computer located at a remote place using mains signalling system. The data is being transferred with the help of modem which uses a principle of ASK (Amplitude Shift Keying). A modem is a circuit that translate digital data into audio tone frequencies for transmission
To communicate within a building or between two nearer buildings a power line intercom is a very practical means. They are very practical and economical since no wiring is needed between two intercoms. Instead they use the mains line to pass the signal. Frequency modulation is done on this carrier with the audio and transmitted to the mains line. Since FM is used, the noises and interruptions present in the power line do not affect the clarity of the audio.
MAIN FEATURES OF THE PROJECT:
 Since a majority of components are common for the transmitter and the receiver, the cost and size of the intercom are reduced almost to half.
 When there is no audio, the amplifier input is disconnected in order to avoid the noise in the speaker.
 When receiving an audio do not change over to transmitter even if we press the push-to-talk button and hence the audio is not lost.
 No separate wiring is required since power lines will be utilized.
 The results obtained are quite reliable.
1.4 STATEMENT OF THE PROBLEM
Several options, with different costs, can provide voice and data communication service. The simplest solution is connecting lines. This solution is potentially quite costly because of the number of lines involved. A wireless system has also been suggested for communication. This option reduces local loop fees, but increases hardware costs and radiation issues would be there. Another alternative involves running high bandwidth lines. These lines could be fiber, ATM, or broadband coaxial cable. This option avoids local loop fees, but is beset by equipment fees. Communication between various departments in the large industries, schools or in hospitals requires large amount of resources and it is so difficult to maintain.
1.5 PROBLEM FORMULATION
The actual deployment of Digital Powerline will probably involve a mix of alternatives, optimized for cost efficiency in different areas and with different service providers. The proposed system is to develop a communication system that is easy to setup and even easier to use. Without new wires, powerline communications can be used to bring high-speed communication. So by using powerline communication we can achieve efficient way of communication between various departments in industries, schools or in hospitals.
Powerline communications over wireless technologies provide:
• More reliable for streaming media
• Faster speeds with fewer dropouts
• Whole-home coverage
• Extends the range of wireless technology through Wi-Fi extenders that bridge your wireless and power line networks
• Greater security (all products are sold with encryption turned on)
• Setup takes just a few minutes - just plug in!