ACKNOWLEDEMENT
We thank most of all God Almighty for his mercies and grace that kept us all through our seminar research and for giving us wisdom that was implemented in course of the research work.
We are greatly indebted to our supervisor, ENGR. JOHN CHUKWU for his love, courage, guidance and investment to the group, who sacrificed his time and schedule just to make sure that the best is been brought out from this group and also to the group leader who consistently made every effort and spent sleepless night ensuring that the seminar topic research was a worthwhile and fulfilling one, also to us been the group members who contributed to the success of the research topic.
We also want to thank the head of engineering department(HOD) who also contributed in his own way and also to school for bringing out the seminar format which guided us well and made our work easier.
And to our most beloved parents, guardians which God used in providing the financial resources for us. We say a very big thank you to them all and pray that God bless us all.
THANKS

CHAPTER ONE
INTRODUCTION
DEFINITIONS OF SOME TERMS
A DIGITAL SYSTEM is a data technology that uses discrete (discontinuous) values. By contrast, non-digital (or analog) systems represent information using a continuous function. Although digital representations are discrete, the information represented can be either discrete, such as numbers and letters or continuous, such as sounds, images, and other measurements.
The word digital comes from the same source as the words digit and digitus (the Latin word for finger), as fingers are used for discrete counting. It is most commonly used in computing and electronics, especially where real-world information is converted to binary numeric form as in digital audio and digital photography.
DIGITAL TRANSMISSION SYSTEM is a transmission system in which (a) all circuits carry digital signals and (b) the signals are combined into one or more serial bit streams that include all framing and supervisory signals.
TELECOMMUNICATION in the modern era is the science and practice of transmitting information by electromagnetic means.
MODULATION is the shaping of a signal to convey information or it can be said to be the super-imposition of high frequency into low frequency radiation.
DEMODULATION is the act of extracting the original information-bearing signal from a modulated carrier wave. A demodulator is an electronic circuit (or computer program in a software-defined radio) that is used to recover the information content from the modulated carrier wave.
TRANSMISSION(abbreviation: Tx) in telecommunication is the process of sending and propagating an analogue or digital information signal over a physical point-to-point or point-to-multipoint transmission medium, either wired, optical fiber or wireless. Transmission technologies and schemes typically refer to physical layer protocol duties such as modulation, demodulation, line coding, equalization, error control, bit synchronization and multiplexing, but the term may also involve higher-layer protocol duties, for example, digitizing an analog message signal, and source coding (compression).
TELEVISION (TV) is a telecommunication medium for transmitting and receiving moving images that can be monochrome (black-and-white) or colored, with or without accompanying sound.
DATA TRANSMISSION, digital transmission, or digital communications is the physical transfer of data (a digital bit stream) over a point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical fibres, wireless communication channels, and storage media. The data are represented as an electromagnetic signal, such as an electrical voltage, radio wave, microwave, or infrared signal.
But for the sake of this topic, we shall talk extensively on digital transmission which is also data transmission.

BACKGROUND OF THE STUDY
Applications and History
In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages such as coded drumbeats, lung-blown horns, and loud whistles. In modern times, telecommunications involves the use of electrical devices such as the telegraph, telephone, and teleprinter, as well as the use of radio, microwave transmission towers, fiber optics, orbiting satellites and the Internet, which is a vast world-wide computer network.
A revolution in wireless telecommunications began in the first decade of the 1900s with pioneering developments in radio communications by Nikola Tesla and Guglielmo Marconi. Marconi won the Nobel Prize in Physics in 1909 for his efforts. Other highly notable pioneering inventors and developers in the field of electrical and electronic telecommunications include Charles Wheatstone and Samuel Morse (telegraph), Alexander Graham Bell (telephone), Edwin Armstrong, and Lee de Forest (radio), as well as John Logie Baird and Philo Farnsworth (television).
Data (mainly but not exclusively informational) has been sent via non-electronic (e.g. optical, acoustic, mechanical) means since the advent of communication. Analog signal data has been sent electronically since the advent of the telephone. However, the first data electromagnetic transmission applications in modern time were telegraphy (1809) and teletypewriters (1906), which are both digital signals. The fundamental theoretical work in data transmission and information theory by Harry Nyquist, Ralph Hartley, Claude Shannon and others during the early 20th century, was done with these applications in mind.
Data transmission is utilized in computers in computer buses and for communication with peripheral equipment via parallel ports and serial ports such us RS-232 (1969), Firewire (1995) and USB (1996). The principles of data transmission is also utilized in storage media for Error detection and correction since 1951.
Data transmission is utilized in computer networking equipment such as modems (1940), local area networks (LAN) adapters (1964), repeaters, hubs, microwave links, wireless network access points (1997), etc.
In telephone networks, digital communication is utilized for transferring many phone calls over the same copper cable or fiber cable by means of Pulse code modulation (PCM), i.e. sampling and digitization, in combination with Time division multiplexing (TDM) (1962). Telephone exchanges have become digital and software controlled, facilitating many value added services. For example the first AXE telephone exchange was presented in 1976. Since late 1980s, digital communication to the end user has been possible using Integrated Services Digital Network (ISDN) services. Since the end of 1990s, broadband access techniques such as ADSL, Cable modems, fiber-to-the-building (FTTB) and fiber-to-the-home (FTTH) have become wide spread to small offices and homes. The current tendency is to replace traditional telecommunication services by packet mode communication such as IP telephony and IPTV.
Transmitting analog signals digitally allows for greater signal processing capability. The ability to process a communications signal means that errors caused by random processes can be detected and corrected. Digital signals can also be sampled instead of continuously monitored. The multiplexing of multiple digital signals is much simpler to the multiplexing of analog signals.
Because of all these advantages, and because recent advances in wideband communication channels and solid-state electronics have allowed scientists to fully realize these advantages, digital communications has grown quickly. Digital communications is quickly edging out analog communication because of the vast demand to transmit computer data and the ability of digital communications to do so.
The digital revolution has also resulted in many digital telecommunication applications where the principles of data transmission are applied. Examples are second-generation (1991) and later cellular telephony, video conferencing, digital TV (1998), digital radio (1999), telemetry, etc.
The Process to Improve Modern Digital Transmission.
They are:
1. Telecommunication Transmission: is an act by which a device and system transmit electronic or optical signal across long distance, which enable people around the world to connect or contact on another, to access information also to communicate form remote area. It usually involves one sender of information and one or more recipient’s limited technology such as Telephone, television, radio receiver system etc. These helps to improve the key medium for delivering news, data, information and entertainment.
2. Data Transmission: It’s a means of transmitting data information instantly from one person to another. An example is emailing or electronic mail or common word we use which is email,is a key attraction to internet and is a common form of computer telecommunication. Its also a test based message delivery system that allows information that allows information such as typed messages and multimedia to be sent to individual computer users. Instant messaging is another improve development in telecommunication. It involves sending data in form of text, audio, or video data in real time, E.g. Social Network; whatsapp,facebook,yahoo,2go etc. All these helps to improve digital communication.
3. Electricity Transmission: It’s the process of electric current from one substation to another to the final consumer. The modern way to transmit electricity is by the use of digital control panel and this digital control panel brought the improvement in the transmission of electricity. Electricity is the power source to every other digital telecommunication transmission system.
STATEMENT OF THE STUDY
Data transmission, digital transmission, or digital communications is the physical transfer of data (a digital bit stream) over a point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical fibres, wireless communication channels, and storage media. The data are represented as an electromagnetic signal, such as an electrical voltage, radiowave, microwave, or infrared signal.
While analog transmission is the transfer of a continuously varying analog signal, digital communications is the transfer of discrete messages. The messages are either represented by a sequence of pulses by means of a line code (baseband transmission), or by a limited set of continuously varying wave forms (passband transmission), using a digital modulation method. The passband modulation and corresponding demodulation (also known as detection) is carried out by modem equipment. According to the most common definition of digital signal, both baseband and passband signals representing bit-streams are considered as digital transmission, while an alternative definition only considers the baseband signal as digital, and passband transmission of digital data as a form of digital-to-analog conversion.
Data transmitted may be digital messages originating from a data source, for example a computer or a keyboard. It may also be an analog signal such as a phone call or a video signal, digitized into a bit-stream for example using pulse-code modulation (PCM) or more advanced source coding (analog-to-digital conversion and data compression) schemes. This source coding and decoding is carried out by codec equipment.
Synchronous Transmission
The term synchronous is used to describe a continuous and consistent timed transfer of data blocks.
Synchronous data transmission is a data transfer method in which a continuous stream of data signals is accompanied by timing signals (generated by an electronic clock) to ensure that the transmitter and the receiver are in step (synchronized) with one another. The data is sent in blocks (called frames or packets) spaced by fixed time intervals.
Synchronous transmission modes are used when large amounts of data must be transferred very quickly from one location to the other. The speed of the synchronous connection is attained by transferring data in large blocks instead of individual characters.
Synchronous transmission synchronizes transmission speeds at both the receiving and sending end of the transmission using clock signals built into each component. A continual stream of data is then sent between the two nodes.
The data blocks are grouped and spaced in regular intervals and are preceded by special characters called syn or synchronous idle characters. See the following illustration.
Synchronous Transmission After the sync characters are received by the remote device, they are decoded and used to synchronize the connection. After the connection is correctly synchronized, data transmission may begin.
An analogy of synchronous transmission would be the transmission of a large text document. Before the document is transferred across the synchronous line, it is first broken into blocks of sentences or paragraphs. The blocks are then sent over the communication link to the remote site.
The timing needed for synchronous connections is obtained from the devices located on the communication link. All devices on the synchronous link must be set to the same clocking.
CHARACTERISTICS OF SYNCHRONOUS COMMUNICATION
• There are no gaps between characters being transmitted.
• Timing is supplied by modems or other devices at each end of the connection.
• Special syn characters precede the data being transmitted.
• The syn characters are used between blocks of data for timing purposes.
• Due to there being no start and stop bits the data transfer rate is quicker although more errors will occur, as the clocks will eventually get out of sync, and the receiving device would have the wrong time that had been agreed in the protocol for sending/receiving data, so some bytes could become corrupted (by losing bits).
• Ways to get around this problem include re-synchronization of the clocks and use of check digits to ensure the bytes is correctly interpreted and received.
• Most network protocols (such as Ethernet, SONET, Token Ring) use synchronous transmission.
Asynchronous Transmission
In contrast, asynchronous transmission works in spurts and must insert a start bit before each data character and a stop bit at its termination to inform the receiver where it begins and ends.
The term asynchronous is used to describe the process where transmitted data is encoded with start and stop bits, specifying the beginning and end of each character.
An example of synchronous transmission is shown in the following figure.
Asynchronous Transmission These additional bits provide the timing or synchronization for the connection by indicating when a complete character has been sent or received; thus, timing for each character begins with the start bit and ends with the stop bit.
When gaps appear between character transmissions, the asynchronous line is said to be in a mark state. A mark is a binary 1 (or negative voltage) that is sent during periods of inactivity on the line as shown in the following figure.
Mark (idle) bits in the data stream When the mark state is interrupted by a positive voltage (a binary 0), the receiving system knows that data characters are going to follow. It is for this reason that the start bit, which precedes the data character, is always a space bit (binary 0) and that the stop bit, which signals the end of a character, is always a mark bit (binary 1).
CHARACTERISTICS OF ASYNCHRONOUS COMMUNICATION
• Each character is preceded by a start bit and followed by one or more stop bits.
• Gaps or spaces between characters may exist.
• With asynchronous transmission, a large text document is organized into long strings of letters (or characters) that make up the words within the sentences and paragraphs. These characters are sent over the communication link one at a time and reassembled at the remote location.
• In asynchronous transmission, ASCII character would actually be transmitted using 10 bits. For example, "0100 0001" would become "1 0100 0001 0". The extra one (or zero, depending on parity bit) at the start and end of the transmission tells the receiver first that a character is coming and secondly that the character has ended. This method of transmission is used when data are sent intermittently as opposed to in a solid stream. In the previous example the start and stop bits are in bold.
• The start and stop bits must be of opposite polarity. This allows the receiver to recognize when the second packet of information is being sent.
• Asynchronous transmission is used commonly for communications over telephone lines
How Digital Antenna Works Line of Sight
To understand how a digital antenna works, you must first understand how television signal transmission works. A television station will transmit a signal containing its programming in essentially a straight line. (This is called "line of sight.") However, due to the curve of the Earth (which changes roughly every 80 or so miles), televisions farther away from the transmission source won't necessarily be able to pick up that signal. A digital antenna allows your television to pick up that signal, as long as it is within the overall range of the source, despite the curve of the Earth.
Broadcasts
Unlike having digital cable, where your television programming is sent directly into your home via a cable, local TV stations will simply send out a broadcast and whoever is within range can pick up the signal at no additional charge. Roughly 80 percent of all households will be able to pick up at least five digital stations for free with a digital antenna, barring any physical obstacles like mountain ranges. The digital antenna will receive the television signal and convert it into audio and video information that can then be displayed by your television.
Quality
Contrary to popular belief, over-the-air broadcasts (the kind received by an antenna) are actually of higher picture quality than cable or satellite television. Cable television may offer a huge number of channels, but that visual information is compressed to be transmitted through a cable into your house. When a television station broadcasts over-the-air, that information is going out completely uncompressed. This will result in a better looking and sounding picture than even the highest quality cable box can provide.
Transmission band
There are various bands on which televisions operate depending upon the country. The VHF and UHF signals in bands III to V are generally used. Lower frequencies do not have enough bandwidth available for television. Although the BBC initially used Band I VHF at 45 MHz, this frequency is (in the UK) no longer in use for this purpose. Band II is used for FM radio transmissions. Higher frequencies behave more like light and do not penetrate buildings or travel around obstructions well enough to be used in a conventional broadcast TV system, so they are generally only used for MMDS and satellite television, which uses frequencies from 2 to 12 GHz. TV systems in most countries relay the video as an AM (amplitude-modulation) signal and the sound as an FM (frequency-modulation) signal. An exception is France, where the sound is AM.
OBJECTIVES
Television Systems and Transmission
The objective of the Television Systems and Transmission group is to provide the necessary technological knowledge in advanced television systems and transmission technologies to Industry Canada and to the broadcast and telecommunications industry. Fields of expertise include digital television and enhancements to NTSC television. The group supports Industry Canada in meeting its mandate on spectrum management and in developing regulatory frameworks for broadcasting. Guidance is provided to broadcast and telecommunications industries in implementing new broadcast services and developing new equipment.The Television Systems and Transmission group is responsible for monitoring and identifying trends in television transmission technologies and contributing to the planning of future research.
SOCIAL IMPACT
Telecommunication has played a significant role in social relationships. Nevertheless devices like the telephone system were originally advertised with an emphasis on the practical dimensions of the device (such as the ability to conduct business or order home services) as opposed to the social dimensions. It was not until the late 1920s and 1930s that the social dimensions of the device became a prominent theme in telephone advertisements. New promotions started appealing to consumers' emotions, stressing the importance of social conversations and staying connected to family and friends.
Since then the role that telecommunications has played in social relations has become increasingly important. In recent years, the popularity of social networking sites has increased dramatically. These sites allow users to communicate with each other as well as post photographs, events and profiles for others to see. The profiles can list a person's age, interests, sexual preference and relationship status. In this way, these sites can play important role in everything from organising social engagements to courtship.[42]
Prior to social networking sites, technologies like short message service(SMS) and the telephone also had a significant impact on social interactions. In 2000, market research group Ipsos MORI reported that 81% of 15 to 24 year-old SMS users in the United Kingdom had used the service to coordinate social arrangements and 42% to flirt.
OTHER IMPACTS
In cultural terms, telecommunication has increased the public's ability to access to music and film. With television, people can watch films they have not seen before in their own home without having to travel to the video store or cinema. With radio and the Internet, people can listen to music they have not heard before without having to travel to the music store.
SCOPE AND CONSTRAINTS OF THE STUDY
Data Transmission Modes
There are three ways for transmitting data from one point to another,viz; 1.Simplex: 1. In simplex mode the communication can take place only in one direction. The receiver receives the signal from the transmitting device. This mode of flow of information is Unidirectional. Example: Radio, T.V., Pager transmission.
2.Half-duplex: In half-duplex mode the communication channel is used in both directions, but only in one direction at a time. Thus a half-duplex line can alternately send and receive data.Example is the wireless communication.
3.Full-duplex: In full duplex the communication channel is used in both directions at the same time. Use of full-duplex line improves the efficiency as the line turn-around time required in half-duplex arrangement is eliminated. Example of this mode of transmission is the telephone line.
Digital transmission or data transmission traditionally belongs to telecommunications and electrical engineering. Basic principles of data transmission may also be covered within the computer science/computer engineering topic of data communications, which also includes computer networking or computer communication applications and networking protocols, for example routing, switching and inter-process communication. Although the Transmission control protocol (TCP) involves the term "transmission", TCP and other transport layer protocols are typically not discussed in a textbook or course about data transmission, but in computer networking.
The term tele transmission involves the analog as well as digital communication. In most textbooks, the term analog transmission only refers to the transmission of an analog message signal (without digitization) by means of an analog signal, either as a non-modulated baseband signal, or as a pass band signal using an analog modulation method such as AM or FM. It may also include analog-over-analog pulse modulatated baseband signals such as pulse-width modulation. In a few books within the computer networking tradition, "analog transmission" also refers to pass band transmission of bit-streams using digital modulation methods such as FSK, PSK and ASK. Note that these methods are covered in textbooks named digital transmission or data transmission, for example.
The theoretical aspects of data transmission are covered by information theory and coding theory.
Serial and Parallel Transmission
In telecommunications, serial transmission is the sequential transmission of signal elements of a group representing a character or other entity of data. Digital serial transmissions are bits sent over a single wire, frequency or optical path sequentially. Because it requires less signal processing and less chances for error than parallel transmission, the transfer rate of each individual path may be faster. This can be used over longer distances as a check digit or parity bit can be sent along it easily.
In telecommunications, parallel transmission is the simultaneous transmission of the signal elements of a character or other entity of data. In digital communications, parallel transmission is the simultaneous transmission of related signal elements over two or more separate paths. Multiple electrical wires are used which can transmit multiple bits simultaneously, which allows for higher data transfer rates than can be achieved with serial transmission. This method is used internally within the computer, for example the internal buses, and sometimes externally for such things as printers, The major issue with this is "skewing" because the wires in parallel data transmission have slightly different properties (not intentionally) so some bits may arrive before others, which may corrupt the message. A parity bit can help to reduce this. However, electrical wire parallel data transmission is therefore less reliable for long distances because corrupt transmissions are far more likely.
SIGNIFICANCE OF STUDY
Modern telecommunication centres on the problems involved in transmitting large volumes of information over long distances without damaging loss due to noise and interference. The basic components of a modern digital telecommunications system must be capable of transmitting voice, data, radio, and television signals. Digital transmission is employed in order to achieve high reliability and because the cost of digital switching systems is much lower than the cost of analog systems. In order to use digital transmission, however, the analog signals that make up most voice, radio, and television communication must be subjected to a process of analog-to-digital conversion. (In data transmission this step is bypassed because the signals are already in digital form; most television, radio, and voice communication, however, use the analog system and must be digitized.) In many cases, the digitized signal is passed through a source encoder, which employs a number of formulas to reduce redundant binary information. After source encoding, the digitized signal is processed in a channel encoder, which introduces redundant information that allows errors to be detected and corrected. The encoded signal is made suitable for transmission by modulation onto a carrier wave and may be made part of a larger signal in a process known as multiplexing. The multiplexed signal is then sent into a multiple-access transmission channel. After transmission, the above process is reversed at the receiving end, and the information is extracted.
Advantages of Digital Transmission
• Digital encoding carries a number of advantages over older analog signals. In the first place,
• it uses much less space on the bandwidth, which means it can transfer more information more quickly.
• Digital transmissions can also be compressed more readily--through technology such as MPEG--which renders the signal even smaller. Perhaps more importantly, the signal itself isn't subject to the noise and distortion of analog signals.
• Either the data arrives or it doesn't, and when it arrives, it arrives with clarity and perfection. That also allows digital information to be stored much more easily and cheaply.

CHAPTER TWO
LITERATURE REVIEW
ABSTRACT
A data transmission system includes a transmitter configured to transmit a data signal in the form of a data stream of data bursts in at least two transmission modes to a receiver, in the first mode a reference signal being transmitted by the transmitter in each data burst and being evaluated in the receiver, and in the second mode no reference signal being transmitted by the transmitter in each data burst. In the second mode, in place of the reference signal, additional redundancy data of the data signal are transmitted in each data burst.
CLAIMS
1. A data transmission system, comprising: a transmitter configured to transmit a data signal to a receiver as a data stream of data bursts in either a first transmission mode or a second transmission mode, wherein the transmitter is configured to perform the following: in the first transmission mode, a reference signal is transmitted by the transmitter in each data burst, the reference signal being evaluated in the receiver; in the second transmission mode, transmission of the reference signal by the transmitter in each data burst is avoided, and instead transmission of additional redundancy data of the data signal in each data burst is provided; anda selection between the first transmission mode and the second transmission mode is made dependent on whether interference elimination is performed at the receiver or at the transmitter.

2. The system according to claim 1, wherein the additional redundancy data are provided by data of the data signal that are transmitted in repetition.

3. The system according to claim 1, wherein the transmitter is further configured to perform the following: in the second transmission mode, eliminating interference in the transmitter.

4. The system according to claim 1, wherein the transmitter is further configured to transmit a plurality of data streams simultaneously according to a CDMA technique.

5. The system according to claim 1, wherein the data bursts have at least two data blocks, between which a block is arranged which is used, in the first transmission mode, for the reference signal, and which is used, in the second transmission mode, for the additional redundancy data.

6. The system according to claim 1, wherein the transmitter is further configured to select a data format for the data signal to be transmitted in both the first transmission mode and the second transmission mode so as to be identical.

CHAPTER THREE
Summary:
1. Analog transmission conveys voice, data, image, signal, or video information using an information signal that is continuously varying; digital transmission transfers data over a transmission medium discretely.
2. Analog transmission can be conveyed in four ways: a twisted pair or coax cable, a fibre optic cable, the air, or water; digital transmission may be transmitted via an electro-magnetic signal, such as a microwave. CONCLUSION
Modern telecommunication centre’s on the problems involved in transmitting large volumes of information over long distances without damaging loss due to noise and interference. The basic components of a modern digital telecommunications system must be capable of transmitting voice, data, radio, and television signals. Digital transmission is employed in order to achieve high reliability and because the cost of digital switching systems is much lower than the cost of analog systems.
Also its to be noted that electricity is the power source to every other digital telecommunication transmission system and telecommunication transmission helps to improve the key medium for delivering news, data, information and entertainment.
RECOMMENDATION

REFERENCE
1. A. P. Clark , "Principles of Digital Data Transmission", Published by Wiley, 1983
2. David R. Smith, "Digital Transmission Systems", Kluwer International Publishers, 2003, ISBN 1-4020-7587-1.
3. Sergio Benedetto, Ezio Biglieri, "Principles of Digital Transmission: With Wireless Applications", Springer 2008, ISBN 0-306-45753-9, ISBN 978-0-306-45753-1.
4. Simon Haykin, "Digital Communications", John Wiley & Sons, 1988. ISBN 978-0-471-62947-4.
5. John Proakis, "Digital Communications", 4th edition, McGraw-Hill, 2000. ISBN 0-07-232111-3.
6. Roger L. Freeman, “Reference Manual for Telecommunications Engineering” Published Online: 15 JAN 2002. DOI: 10.1002/0471208051.fre024.
7. Google.Com