Design And Construction Of A Digital Audio Video Input Selector

ABSTRACT

Digital video is an electronic representation of moving visual images (video) in the form of encoded digital data. Digital video comprises a series of digital images displayed in rapid succession, while an audio signal is a representation of sound, typically as an electrical voltage. Audio signals have frequencies in the audio frequency range of roughly 20 to 20,000 Hz (the limits of human hearing). Audio signals may originate at a transducer such as a microphone, musical instrument pickup, phonograph cartridge, or tape head. However, in a case whereby a user has these appliances at home and wants to use them one after the other without constantly plugging the one he wants to use at that point in time and remove the cables he is fade up with, this device does the work. This selector has the ability to accept different input from different transducers or audiovisual appliances and to give out one output which is to be selected by the user

CHAPTER ONE

1.0                                                        INTRODUCTION

In the current field of home entertainment, the use of the basic television sets has expanded far beyond the reception of broadcast television programming. Television sets are now used to receive and display audiovisual or audio signals from a number of sources. For example, a video cassette recorder (“VCR”) uses a magnetic head to read an audiovisual signal recorded on a magnetic tape. This signal can be provided to the television set and displayed to allow the user to watch the recorded programming. Digital video disk (“DVD”) players perform the same function except that the programming is recorded on an optical disc and read optically by the DVD player.

Additionally, a television set may be connected to a cable from Digital video disk to a television system to which the user has subscribed, and at a time the viewer become fade up with the program displaying on the tv and wants to play an audio cassette without going to the tv to remove the Digital video disk plug in order to plug the audio cassette plug so that the output maybe received. This device does this function just by turning the switch which is also called a selector.

This device was originally made for common output selection for consumer audiovisual devices sold in electronics shops in Nigeria. The choice allowed the user to select one output from the multiple input devices in their homes or offices so that the connected device would be able to provide single video and audio on an RF feed to the television or order output display device without changing the signal cable at all time

This digital audio video selector allows you to conveniently connect up to three optical fiber signals to one sets of signal receiving device. It switch audio signal without loss of quality or degradation. You can manually disconnecting/connecting the appropriate optical audio cable by switch control. And connect the output port with fiber input device through fiber cable.

1.1                                         BACKGROUND OF THE PROJECT

This work is on a digital audio video input Selector. A selector can be electrical or mechanical component called a switch. In electrical engineering, a switch is an electrical component that can “make” or “break” an electrical circuit, interrupting the current or diverting it from one conductor to another. The mechanism of a switch removes or restores the conducting path in a circuit when it is operated. It may be operated manually, for example, a light switch or a keyboard button, may be operated by a moving object such as a door, or may be operated by some sensing element for pressure, temperature or flow. A switch will have one or more sets of contacts, which may operate simultaneously, sequentially, or alternately. Switches in high-powered circuits must operate rapidly to prevent destructive arcing, and may include special features to assist in rapidly interrupting a heavy current. Multiple forms of actuators are used for operation by hand or to sense position, level, temperature or flow.

For the course of this work, this device selects more than one possible paths for audiovisual signal at a time, and it does this by direct human interaction. This device makes it convenient to connect devices such as DVD player, Video game player, Set-top box, PC and USB devices.

1.2                                                   AIM OF THE PROJECT

The objective of this work is to construct a device that permit connection of more than one audio-video (AV) source to your colour television that allows the selection of one output at a time.

1.3                                             OBJECTIVE OF THE PROJECT

At the end of this work, students involved will be able to:

1. Learn and understand the principle of multiplexing
2. Also learn about optic fiber cable

• Learn about audio and video signals

1. Audio and video connectors are discussed.

1.4                                              PURPOSE OF THE PROJECT

The main purpose of this work is to selector one audio/video signal from the rest of the audio video signal connected to the device.

1.5                                          APPLICATION OF THE PROJECT

This device can be used in places like:

1. Home/portable digital audio components with optical connection,
2. MP3/CD/DVD player including Blu-ray/HD DVD,
3. video game consoles,
4. computer sound card,
5. cable/satellite receiver to your home theater system with a digital optical input.

1.6                                         SIGNIFICANCE OF THE PROJECT

• (bi-directional: can go in reverse direction)
• Allows you to connect up to three audio/video sources to one input
• Jacks are compative with fiber optic cables with connectors at each end
• Provides interference and distortion free signal transmission(0 db signal loss)
• Signals can be passed through this unit.
• It is inexpensive and easy to construct.

1.7                                                 SCOPE OF THE PROJECT

The circuit was built around CD4017 decade counter IC which made this work simple and straightforward. Whenever 12V DC is applied to the circuit, power-on LED1 glows. Now reset the decade counter by momentarily pressing switches S2 to make Q0 output of IC1 high. LED2 glows to indicate that the circuit is ready to work. Switch S1 is used for selecting a particular audio-video (AV) signal. To select the first AV signal, press switches S1 once. To select the second AV signal, press switches S1 twice. In the same way, you can select the other two signals.

AV input is a common label on a connector to receive (AV) audio/visual signals from electronic equipment that generates AV signals (AV output). These terminals are commonly found on such equipment as a television, DVD recorder or VHS recorder, and typically take input from a DVD player, a TV tuner, VHS recorder or camcorder.

1.8                                        PROJECT WORK ORGANISATION

The various stages involved in the development of this project have been properly put into five chapters to enhance comprehensive and concise reading. In this project thesis, the project is organized sequentially as follows:

Chapter one of this work is on the introduction to the study. In this chapter, the background, significance, objective, aim, purpose, application,  and scope of the study were discussed.

Chapter two is on literature review of this study. In this chapter, all the literature pertaining to this work was reviewed.

Chapter three is on design methodology. In this chapter all the method involved during the design and construction were discussed.

Chapter four is on testing analysis. All testing that result accurate functionality was analyzed.

Chapter five is on conclusion, recommendation and references.