Objectives

Upon the completion of this topic the student will be able to explain

• Formation of picture

• Reproduction of Motion picture &TV picture

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TELEVISION PICTURETELEVISION PICTUREFUNDAMENTALSFUNDAMENTALS

• TRANSMITTER

• RECEIVER

• CHANNEL

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Block Diagram of a Communication System

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TRANSMITTER RECEIVERCHANNEL

Block Diagram of a Communication System

• LINE (WIRE) COMMUNICATION

• WIRELESS COMMUNICATION

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CLASSIFICATION

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TRANSMITTER RECEIVERCo-axial Cable

Examples of system are

•Telephony

•Telegraphy

Line Communication System

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RECEIVERTRANSMITTER

Wireless Communication System

• AUDIO or SOUND SIGNALAUDIO or SOUND SIGNAL

• VIDEO or PICTURE SIGNALVIDEO or PICTURE SIGNAL

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T.V. SIGNAL

SSB

• Suppressing LSB, loss of DC component i. loss of background information

• Suppressing USB, loss of high frequency components

• i.e. loss of finest details in the picture.

TYPES OF AMPLITUDE MODULATION

• AMPLITUDE MODULATIONAMPLITUDE MODULATION

It is used for Picture

• FREQUENCY MODULATIONFREQUENCY MODULATION

It is It is used for Sound

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TYPES OF MODULATION

Characteristics of human eye

VISUAL ACUITY

PERSISTENCE OF VISION

BRIGHTNESS AND COLOUR SENSATION

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VISUAL ACUITY

• It is the ability to resolve the finer details in a picture

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PERSISTENCE OF VISION

• Property of the eye to retain its vision for

sometime, after the source of light is removed.

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Brightness & Colour Sensation

• Property of the eye to sense the brightness and

colour variations in a picture.

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• NUMBER OF LINES

• SCANNING RATE

• SPECTRAL RESPONSE REQUIREMENTS

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IMPORTANT REQUIREMENTS OF SCANNING

• VISUAL ACUITY

Determines the number of lines

• PERSISTENCE OF VISION Determines the rate of scanning

• BRIGHTNESS AND COLOUR SENSATION

Determines the spectral response requirements

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CHARACTERISTICS OF HUMAN EYE & REQUIREMENTS OF SCANNING

STILL PICTURE

• A still black and white picture is an fundamentally arrangement of many small dark and light areas, known as pixels or picture elements.

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• These black and white areas are converted into electrical currents and transmitted.

• The picture can be easily reproduced at receiver just by converting those electrical currents into corresponding picture information.

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• To transmit any picture, light information must be

converted into electrical form by scanning method

• Picture scanning is similar to reading of a page from left

to right and from top to bottom.

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• In TV system, CRT uses an electron beam to scan the

picture details at every point on every line

• Each still picture can be considered as a frame

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PICTURE

Picture Reproduction is done by Duplicating its Picture Elements

FORMATION OF PICTURE

FORMATION OF PICTURE

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PICTURE DIVIDED INTO ELEMENTS

PIXEL

Picture Reproduction by Duplicating its Picture Elements

SUMMARY

We have discussed about

• FUNDAMENTALS OF TV

• FORMATION OF PICTURE

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QUIZ

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1. Pixel is a

a. picture element

b. sound element

c. none

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Frequently asked questions

1. What is persistence of vision?

2. Explain the formation of picture in Television.

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THANK Q

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