Fundamentals of Information Technology

(IT-162)

Meer Qaisar Javedqaisar.javed@uog.edu.pk

Lecture # 04

Department of Information Technology, University of Gujrat

Lecture Outline

WEEK Topic Lecture

02  Introduction to Information and Communication SystemsComponents of Communication SystemsExamples of Analogue and Digital DevicesRepresenting information in binary formComments for next class

04

Information Systems Information System: The entire infrastructure,

organization, and components that collect, process, store, transmit, display, disseminate, and act on information.

An Information System composed of: people, procedures, software, hardware, & data.

Components of Communication Systems

Input Transducer- Also known as a sensor. Converts a physical signal to an electrical, optical, or electromagnetic signal.

Transmitter - A device that sends the transduced signal to a receiver.

Transmission Channel - A physical medium by which a signal is carried.

Receiver - A device that recovers a transmitted signal from the transmission channel.

Output Transducer - A device that converts the received signal back into a useful physical quantity.

TV Transmissions.Example of a Communication System

Phonogram:Information System Example

Breakthrough in the communication of information (sound).

Invented by Thomas Edison. A diaphragm vibrates when it detects sound waves. The diaphragm transfers a vibration to a stylus, which cuts

grooves into a solid material.

Cylinder

Needle

DiaphragmSound Collecting Horn

Telephone System:Information System Example

•Local loops

•Trunks lines

•Switching offices

WWW.Information System Example

HTML – hypertext markup language Universal simple language for formatting embedded of graphic

Hypertext - Generally, any text that contains links to other documents

HTTP - Hypertext Transfer Protocol The protocol for moving hypertext files across the Internet.

Requires a HTTP client program on one end, and an HTTP server program on the other end. HTTP is the most important protocol used in the World Wide Web

Middleware Software that connects two otherwise separate applications OR

separate products that serve as the glue between two applications. It is, therefore, distinct from import and export features that may be built into one of the applications.

WWW….Cont:

Examples of Analog and Digital Devices:

Analog Microphone Cassette player Radio Photograph camera

Digital: DVD Digital camera HDTV CD player Most cell phones Fiber-optic systems

Representing information in binary formIn order to efficiently store, transmit, process and retrieve

information, we need a process for encoding the information.

The encoding process is a method of representing information using a finite number of basic elements, called an alphabet

Examples of written alphabets are: The English alphabet: 26 lower case, 26 upper case, 10 numbers

and 32 special characters=94 characters The Chinese alphabet (Mandarin): 40, 000 characters

The Chinese alphabet is a more powerful code as it can convey

more information with a single complex character (symbol). Fewer characters are required to communicate an idea

However, this code is very complex and the task of distinguishing onecharacter from the other at the receiving end is highly challenging

We would require a more robust scheme since reliable manipulation of information depends upon resistance to errors

The fewer symbols the code has, the easier it is to distinguish the symbols from each other

The alphabet with the minimum number of symbols (2) is called the binary alphabet or code

It consists of two distinct symbols: 1 and 0

Any information can be coded using only these two symbols called bits: Binary digits

Representing information in binary form (cont.)

Why Use a Code with Only Two Values?

A binary system is more resistant to errors The two symbols are highly distinguishable from

one another. The 2 clear values make the system simple and

reliable. Two values correspond well to the “on” and

“off” states of electronic switches that comprise digital computers.

How do Digital Systems Produce 0s and 1s?

Physically, a 1 or a 0 can be produced in several ways: The presence of or level of voltage in an electrical network. A pulse of light or varying of light intensity in an optical network. Discrete variations of signal amplitude in a radio network like

satellite or cellular. STORAGE - To store binary data, storage media must

represent two values. Magnetic disk can be magnetized in two directions “up” or “down” Laser disk domains have either a smooth surface or pitted surface.

TRANSMISSION - Two distinct electrical or optical quantities are transmitted such as a pulse of light and absence of light.

PROCESSING - Computer circuits can be broken down into the fundamental building block, the electronic switch (either “on” or “off”).

Practical Use

Everyday stuff measured in bits: 32-bit sound card 64-bit video accelerator card 128-bit encryption in your browser 650 MB CD

Comments for next class

Go over today’s lecture notes Download next week’s lecture notes Finish reading chapters 1 and 3