CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND OF STUDY
A television transmitter is a device which broadcasts modulated electromagnetic signal to the television receivers; it may be analogue or digital.[1] Years back, information transmission was done through difficult means like travelling to the destination of the second party, posting letters through postal agencies and, receiving secondhand information (verbal) which could be altered in the process. Today, people can travel round the globe at the confines of their home with just a click on a button. The new age of technology has redefined communication in area of television transmission; most people nowadays have access to firsthand information through live streaming.
As technology has advanced, television transmission also taken a step forward in its transmission process. Television transmitter (audio and video sender circuit) employs frequency modulation in the audio stage and amplitude modulation at the video stage. The signal is conveyed either through cables for wired transmission or microwave link for wireless. This signal is then transmitted to a transmitting station where it modulates a carrier and the resultant carrier wave is passed on to the transmitting antenna to be radiated. At the same time, the sound signal associated with the scene is picked up by the microphone and converted into electrical signal. This is also conveyed to the transmitting station where the sound modulates a carrier and the resultant antenna picks the combined vision and sound modulated wave and passed it on to the television receiver. At the receiving end, the receiver amplifies the weak signal, separate vision from sound in a demodulation process; sound is being heard from a connected loudspeaker while the vision is displayed with the help of Cathode Ray Tube (CRT), Liquid Crystal Display (LCD), Light Emitting Diode (LED), or Smart TV devices.[2]
Transmitting technologies in television broadcasting as developed in recent years in other countries of the world goes to show the very fact that improvements are in-fact possible and these improvements have eased our lives and the way we live.
These days, apart from transmitting live broadcast through satellite, transmission is also made possible for home video transmission of which I have used this project work to achieve. The application of the system is immense in the ever changing technological world. It allows in greater degree the ability to use one device to transmit to as many television receivers as possible within the coverage area and reduces cost of purchasing same to go round each receiver.
1.2 AIM AND OBJECTIVES
The project, “Design and Implementation of a Very High Frequency (VHF) Band Television Transmitter” is aimed at achieving a system with 50w power supply to cover a radius range of 65m and transmitting in a frequency of 207MHz.
OBJECTIVES
The general objectives of this project are:
To successfully design a simple TV transmitter,
To implement the TV transmitter with low power consumption,
To provide enhancements for home video distribution,
To provide a reference for further study in a similar stream having ambition to deal with VHF Band TV transmitter.
1.3 MOTIVATION
With the present high cost of laboratory equipment and the inability of the school to provide all that is required to expose the students to telecommunications practical, I was motivated to produce this transmitter to assist in practical experiences in the laboratory.
1.4 STATEMENT OF THE PROBLEM
Technology has advanced so much in the last decade or two that it has made life more efficient and comfortable. The comfort of real time information dissemination from one particular location has become imperative as it saves a lot of time, cost and effort. Parents have the need to choose channels being viewed by the children form a single decoder and distributing it rather than buy multiple connections. This is implemented in this project work.
Presently there is no TV transmitter of any kind for experiment in our Telecommunications Laboratory. As a result, students are incognizant with transmitters in terms of practical knowledge they are expected to acquire. Thus, this project proffers solution to the problem.
1.5 SCOPE OF THE PROJECT
This project is meant to be able to transmit within the Telecommunication Laboratory.
1.6 EXPECTED BENEFIT OF THE PROJECT
When completed and mounted in the laboratory, students will have better exposure to practical experiments in the TV broadcasting technology. Images and sound mixing transmission can then be physically explained and better understood. It will also serve the school the cost of purchasing similar hardware for this purpose.
1.7 PROJECT ORGANISATION
This project is designed to have five chapters, the first chapter gives an introduction to television transmitter along with the project aim and objectives, the motivating factor, the scope of the project, and the expected benefit of the project work.
Chapter two is on literature review which contains a review of similar previously implemented devices. Chapter three explains the engineering steps taken in the selection of the major components used in achieving the hardware part of the project. Chapter four deals with the implementation and testing of the fabricated hardware and Chapter five summarizes and concludes the project work on VHF Band TV Transmitter as well as provide some form of recommendations for those interested in looking beyond the scope of this work.
