use of internet and electronic communication system1

8/7/2019 use of internet and electronic communication system1

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Department of Electronics &

Communication

Course: analog

Communication System

[analog CommunicationSystem]

Topic: Use of internet & Electronic CommunicationSystem

Submitted To: Submitted By:

Mr.Gurushan Singh Aashish Gupta

B-Tech[ECE-

MBA]

10802783

Internet and electronic Communication

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RollNo:

RB6803A09

Introduction:::::

What is the Internet?

The Internethas been called the "network of networks." Simply put, it's a way to linkmillions of people around the world, each of whom is using a computerconnected to a

smaller network such as the one in their office, or school, or to a commercial network

such as America Online or CompuServe.

A network of networks, joining many government, university and private computers

together and providing an infrastructure for the use of E-mail, bulletin boards, file

archives, hypertext documents, databases and other computational resources


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The vast collection of computer networks which form and act as a single huge network

for transport of data and messages across distances which can be anywhere from the

same office to anywhere in the world.

What is Electronic Communication system?

Connecting Computers to a Network_ Network switch_ Network ports in wall connected to switch

_ Network transmissions from computers are independent of each other_ Preferable, but expensive

How internet relate with Communication systemThe Internet is a global system of interconnected computer networks that use the

standard InternetProtocol Suite (TCP/IP) to serve billions of users worldwide. It is anetwork of networks that consists of millions of private, public, academic,

business, and government networks, of local to global scope, that are linked by a broadarray of electronic and optical networking technologies.

Most traditional communications media including:Communication system with internet

Film

Telephone Music


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Television

Are being reshaped or redefined by the Internet.

E-mailis an important communications service available on the Internet.

Internet telephony is another common communications service made possibleby the creation of the Internet

Importance of Communication system:

Communication means the process of exchanging information .it is used for

conveying thoughts, ideas and feelings.

Two of the main barriers in human communication are distance and language.

Out of them the distance problem is solved now a day means of introducing long

distance communication.

The telegraph was invented in 1844 and the telephone in 1876.

Invention of Radio was a huge leap forward in the field of communication.

Radio, T.V uses the Electronic communication and they have increased our

ability to store information.

This has changed oursocietyfrom what it was to what it is now.

Classification of Electronic Communication System:

Classified into Various Categories:

1) Whether the system is Unidirectional or Bidirectional

2) Whether it uses an analog or digital information signal

Classification based on direction of communication system:

Simplex system(Unidirectional System)

Half Duplex system(Bidirectional System)

Full Duplex system(Bidirectional System


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Simplex System:

In this system the information is communicated in only one direction.

For example: the radio or TV broadcasting systems can only transmit. They

cant receive.

Half Duplex system:These systems are Bidirectional .They can transmit as well as receive but not

simultaneously.For Example: Wally talky set

Full Duplex System:

These are truly bidirectional system as they allow the communication to takeplace in both directions simultaneously.

The bulk of electronic Communication however is Two way.For Example: Telephone system

Application of Electronic Communication:


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Simplex (one way) Duplex (two ways)

AMand FM broad casting telephones

TV broadcasting two way radios

Cable TV Radar Wireless remote control Sonar

Navigation and direction finding data communication

Telemetry

Radio Astronomy

Music services

==========================================================================================

====

Modem:

Modem (Modulator/ Demodulator)

It takes digital electrical pulses from a computer, terminal, or microcomputer and

converts them into a continuous analog signal, for transmission over an analog voicegrade circuit.

It then re-converts the analog signal to its original digital format.

Evolution:

Evolution A dumb terminal at an off-site office or store could "dial in" to a large,

central computer. The 1960s were the age of time-shared computers, and the 300-bit-

per-second (bps) modems.

Today:

Today Faster non-analog modems. Users connect to the Internet through a: regular

modem local-area network (LAN) connection cable modem, or digital subscriber line(DSL) connection

Modern modems use combinations of amplitude, frequency, and phase

modulation to achieve high data rates.

The fastest dial-up modem at the moment is 56 Kbps.

Modems can support auto answer, auto dial, auto disconnects, and auto redials.


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Features of Modems

o Operates at the Bell 202 Standard Forward Bit Rate (1200 bits/second)

o Uses 1200 Hz and 2200 Hz Bell 202 Shift Frequencies

o Low Power Consumption (typically 40 uA)

o Accurate Carrier Detect Logic

o Single Chip Frequency Shift Keying (FSK)

o 1200 Baud Transmit and Receive Modulation

o 3 to 5 Volt Power Supply

o CMOS and TTL I/O compatible

o Optimized for Intrinsically Safe Applications

o Uses reliable CMOS technology

o Available in 16 pin DIP or 28 pin PLCC packages

How to design the Modems

The simplest approach to the design of modems is to treat the entire PSTN as a linear

analog network. [Note that PSTN is almost entirely due to the use of pulse-codemodulation (PCM) for the transmission of voice signals.]

In such a setting, analog-to-digital and digital-to-analog conversions are needed

whenever the modems send signals to and receive signals from the PSTN.

The modem configuration depicted in the above figure exhibits 'symmetry' in that both

modems are identical. The data rate downstream (from the ISP to the user) is exactly the

same as the data rate upstream (from the user to the ISP).

Types of modems

External Modem

This is the simplest type of modem to install because you don't have to open thecomputer. External modems have their own power supply and connect with a cable to a

computer's serial port. The telephone line plugs into a socket on the rear panel of themodem.

Because external modems have their own power supply, you can turn off the modem to

break an online connection quickly without powering down the computer


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Internal Modem

Most internal modems come installed in the computer you buy. Internal modems aremore directly integrated into the computer system and, therefore, do not need any

special attention. Internal modems are activated when you run a communication

programme and are turned off when you exit the programme. This convenience isespecially useful for novice users.

Internal modems usually cost less than external modems, but the price difference is

usually small. The major disadvantage with internal modems is their location, inside the

computer

Modems for laptop computers are typically of two forms.

The first type of laptop modem is completely inside the laptop.

A user plugs a modular phone cord (RJ-11) into a slot which is attached to the

modem.

The second type of laptop modem is about the size of a credit card and plugs into a

special connector.

PC Card Modem

These modems, designed for portable computers, are the size of a credit card and fit

into the PC Card slot on notebook and handheld computers. These modems are

removed when the modem is not needed.

Except for their size, PC Card modems are like a combination of external and internal

modems. These devices are plugged directly into an external slot in the portable

computer. So no cable is required other than the telephone line connection.

The cards are powered by the computer, which is fine unless the computer is battery-

operated. Running a PC Card modem while the portable computer is operating on

battery power drastically decreases the life of your batteries.


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Modem Characteristics

The HT2012 HART modem has four main subsections:

Carrier detect,

Clock/timing

Modulation

Demodulation.

Carrier Detect

The carrier detect output is active low whenever a valid carrier tone between 1000 and

2575 Hz (inclusive) is detected. Detection occurs when timed transitions remain within

the band of the 1200 and 2200 Hz periods for 40 Nanno seconds to 1 Bit time.A loss of carrier for 1 millisecond or more causes the carrier detects line to go inactive

high (1).

Carrier Detect Frequency Range:1000 Hz to 2575 Hz The range of frequencies applied at IRXA over which OCD must golow (0).

Time from Carrier Input to Carrier

Detect:

40 nano seconds (Minimum) 1 bit time (Maximum) The time from the start of a validCarrier signal at IRXA until OCD goes to logical low (0).

Conditions:

1. Clock frequency of 460.8 kHz +/- 0.1%

2. Input (IRXA) asymmetry maximum of 5.0%

User Clock Frequency:

Nominal 19.2 kHz

Proportional to the 460.8 kHz

clock at l460K

\Modulator

The modulator takes data to transmit and modulates it as either 1200Hz (mark) a 2200Hz (space). The input signal to transmit is applied to the ITXD pin as an NRZ digitalsignal.

An important feature of the modulatoris its preservation of the phase integrity of eachfrequency when switching between frequencies. This enables accurate reconstruction of

the original modulating signal at the output of the demodulator


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Demodulator

The input signal from the IRXA pin is a digital pulse train consisting of the FSK

modulated square waves. The demodulated data stream is buffered at the ORXD pin asa digital output signal


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Maximum Demodulator Jitter:

+/- 12% of one bit time

Conditions:

1. Input frequencies at 1200 Hz +/- 10 Hz; 2200 Hz +/- 20 Hz2. Clock frequency of 460.8 kHz +/- 0.1%

3. Input (IRXA) asymmetry = 0

Important point related to process of Modem

Cable Modem:

Cable Modem Cable company offers Internet access over the cable Speed at more than

1 mbps (1 million bits per second), or about 20 times faster that 56k modems

Downstream data into a 6-MHz channel looks just like a TV channel Equipment Cable

modem (customer) CMTS (cable provider)

Inside the Cable Modem: Modulator

In cable modems that use the cable system for upstream traffic, a modulator is used to

convert the digital computer network data into radio-frequency signals for transmission.This component is sometimes called a burst modulator, because of the irregular nature

of most traffic between a user and the Internet, and consists of three parts:

A section to insert information used for error correction on the receiving end A QAM modulator

A digital-to-analog (D/A) converter


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Integrating different standards

Broadband access

Home networking

System interfaces

Interface Standards

Many different groups contribute to interface standards:

International Telecommunications Union (ITU) (formerly CCITT)

Electronics Industries Association (EIA)

Institute for Electrical and Electronics Engineers (IEEE)

International Organization for Standards (ISO)

American National Standards Institute (ANSI)

Standards organizations and modem protocols

International Telecommunications Union ITU: Data communication over thetelephone network

Federal Communications Commission TELECOMMUNICATION: PART64_MISCELLANEOUS RULES RELATING TO COMMON CARRIERS

56k

V.92


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Columbia University - Protocols Explained - no longer available, archivedversion

Basic handshakes & modulations - V.22, V.22bis, V.32 and V.34 handshakes

Future scope of internet & Electronic Communication System

What is the future of communication?

The future is shiny.

Fifty years ago,

The tools we rely upon to communicate today were only science fiction.

Today, we can purchase a smartphone and make calls, surf the Web, play games, runapplications and accomplish more than most speculative fiction authors dared to

dream.

So what's next?

In the short term, we'll likely see basic cell phones slowly fade away. As smartphones

become more common and less expensive, more people will adopt them. The process is

gradual. As with most new technologies, a group of enthusiastic adopters lead the way.Sometimes, the general population will follow the early pioneers -- the compact disc is a

good example of such technology.

In other cases, the early adopters end up owning technology that becomes obsolete

without ever finding wide acceptance -- like Laserdiscs.

Smartphones

Smartphones seem to be in the first category.

Products like the AppleiPhoneandGoogle's Androidoperating system have pushed thesmartphone out of the world of gadget geeks and into the mass market.

In 2010, the first 4G smartphone for a major carrier in the United States made an

appearance. It was the HTC EVO 4G, running on Sprint's WiMAX network [source:CNET].

The 4G network allows for faster data transfer speeds than other networks.


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Voice over internet protocol (VOIP)

The Internet will continue to play an increasing role in communication. Voice overInternet protocol (VoIP) already plays a large role in several communication products

and services. Sites like Facebook and Twitter allow users to communicate with networks

of people.

With the rise of the Web, people now have a platform from which they canaddress the world. In the past, only celebrities and politicians could addressso many people at one time. Now, anyone with an Internet connection cando the same thing.

References:

http://www.howstuffworks.com/

http://computer.howstuffworks.com/internet/basics

Data Communications and Computer Networks: A Business Users Approach

ppt

www.wikipedia.com

Electronics Communication System-Wayne Tomasi

Types Of Modems | Tutorvista.com

company related to modem pdf - Google Search

http://www.google.co.in/#sclient=psy&hl=en&q=application+of+internet+and

+electronic+communication&aq=f&aqi=g10&aql=&oq=&gs_rfai=&psj=1&fp

=f80b76cc19427b17


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