Design and Construction of an FM Transmitter
ABSTRACT
This work is title “Construction of an FM Transmitter”. This is an electronic device which with the aid of an antenna produces radio waves. It signal through the help of an electrets microphone.
This work is constructed using component like, electric microphone, transistors, resistors, inductors and capacitors. This work has a electric microphone which converts audio input signal to electrical signal output with the help of a pre-amplifier circuit which modulate the signal to the tank circuit later to the buffer stage to be picked up by an Arial or antenna.
This work is basically a very High Frequency (VHF) colipits oscillator which is capable of transmitting natural sound or music with the help of an electric microphone to any standard FM receiver. It can be used as a cordless microphone mobile phones and for public address purposes.
Design and Construction of an FM Transmitter
CHAPTER ONE
1.0 Introduction
In electronics and telecommunications a transmitter or radio transmitter is an electronic device which, with the aid of an antenna produces ratio waves. The transmitter itself generates a radio frequency; alternating current (AC), which is applied to the antenna when excited by this alternating current, the antenna radiates radio waves.
In addition to their use in broadcasting, transmitters are necessary component parts of many electronic devices that communicate by radio such as cell phones, wireless computer networks, Bluetooth, enables devices, garages door openers, two-way radios in aircraft, ships, and spacecraft, radar sets, and navigational beacons. The turn transmitter is usually limited to acquirement that generates radio waves for communication purposes; or radiolocation such as radar and navigational transmitters.
Generators of radio waves for heating or industrial purposes, such as microwave ovens or diathermy equipment are not usually called transmitters even though they often haves similar circuits. The term is popularly used more specially to refer to a broadcast transmitter, a transmitter used in broadcasting as in FM radio transmitter.
This usage usually includes the transmitter proper, the antenna, and often building it is housed in. a transmitter can be a separate piece of electronic equipment, or an electrical circuit within another electronic device. Transmitter and receiver combined in one unit called a transceiver.
Design and Construction of an FM Transmitter
The term transmitter is often abbreviated “XMTR” or “TX” in technical documents. The information is provided to the transmitter in the form of an electronic signal such as an audio (sound) signal from a microphone. The transmitter combine the information signal to be carried with the radio frequency signal which generates the radio waves, which is often called the carrier wave.
This process is called modulation. The information can be added to the carrier in several different ways in different types of transmitter in a Frequency Modulation (FM) transmitter, it is added by varying the radio signal’s frequency slightly. Many other types of modulation are used.
The antenna may be enclosed inside the cases or attached to the outside of the transmitter, as in portable devices such as cell phones, walkie-talkies, and garages door openers. In more powerful transmitters, the antenna may be located on top of a building or on a separates tower, and connected to the transmitter by a feed line, that is a transmission line.
Design and Construction of an FM Transmitter
1.1 Purpose of the Study
The main purpose of this work is:
- To construct a device that will allow music or other audio content from a portable media player, CD player or other portable audio system to be played through a nearly FM radio. It can either be a capability built into a portable media player, or a portable appliance that plugs into the headphone jack or proprietary output port of a portable media player or video device. The sound is then broadcast through the transmitter on an FM broadcast band frequency and picked up by the receiver
- The purpose is generally to allow portable audio devices to make use of the better sound quality of a home audio system or car stereo without requiring a wired connection between them. The FM transmitter plugs into the audio output of audio devices and converts the audio output into an FM radio signal, which can then be picked up by appliances such as car or portable radios.
1.2 Objectives of the Study
The objective of this work is to design and construct an FM transmitter which transmits a frequency modulated signal to an FM Radio. That is to construct a device that can broadcast signals on an FM broadcast band and picked up by the receiver. Also it main objective is to create or construct and FM transmitter which transmits it redundancy a signal or sound to an FM receiver without the need for cables.
Design and Construction of an FM Transmitter
1.3 Limitation of the Study
- The relatively low power output of FM transmitters sometimes makes it unsuitable for use in some large urban areas because of the number of other radio signals. This is compounded by the fact that strong FM signals can bleed over into neighboring frequencies making the frequencies unusable with the transmitter.
- Removing a car’s radio antenna has been found to significantly improve transmitter reception. Some frequencies below 88.1 have even been supported as reception frequencies on some car stereos, and some indigenous FM transmitters even take advantages of those unused frequencies which are generally more reliable as no frequency below 88.1 used for mainstream broadcasters in the US.
- Some models which connects via ports other than the headphone jack have no means of controlling the volume which can force the sound to transmit out from the device harshly (causing over modulation), or too low. In theory a devices could use an automatic level control or audio limiter circuit to overcome this problem although there are few (if any) devices with such a facility available out on the market yet.
1.4 Definition of Terms
Antenna: The physical devices used for sending/receiving radio waves
Bandwidth: Bandwidth is used to measure the data throughput of a channel or connection. It’s the amount of data that can be sent over a connection in a given amount of time without distortion, it should not be confused with band.
Band: A specific ranges of frequencies (for example those between 1850MHz and 1995MHz) are called a band.
Hz (Hertz): A unit of frequency measurement equal to one cycle per second.
FM Transmitter: It a device that allows a phone to broadcast music stored in its memory on FM frequencies, so that it can be turned into nearby FM receiver such as a car radio.
Baseband: Is a signal that has a very narrow frequency range.
Multiplexing: Is a method by which multiple analog massage signal or digital data streams are combined into one signal over a shared medium.
Frequency: It is the number of complete cycles per second in alternating current direction.
Broadcasting: broadcast or broadcasting is the distribution of audio and/or video content to a dispersed audience via any electronic mass communications medium.
Spectrum: Is a condition that is not limited to a specific set of values but can vary infinitely within a continuum.
Modulation: It is the addition of information to an electronic or optical carrier signal.
Carrier Signal: it is one with a steady waveform
Design and Construction of an FM Transmitter
Design and Construction of an FM Transmitter
Design and Construction of an FM Transmitter
Design and Construction of an FM Transmitter
Design and Construction of an FM Transmitter
Design and Construction of an FM Transmitter
Design and Construction of an FM Transmitter
