EP301 COMPUTER NETWORKING SYSTEM DATA TRANSMISSION AND NETWORKING MEDIA ALIF IZMER BIN ZULKIFLI (12DEP11F1035) MUHD AZHAR BIN OSMAN (12DEP11F1025) NUR.

EP301 COMPUTER NETWORKING SYSTEM

DATA TRANSMISSION AND NETWORKING MEDIA

ALIF IZMER BIN ZULKIFLI (12DEP11F1035)MUHD AZHAR BIN OSMAN (12DEP11F1025)NUR AZUREEN BT SAHABUDIN (12DEP11F1034)NOOR FARHANA BT ABDULLAH (12DEP11F1022)

WHAT IS DATA TRANSMISSION?

• The physical transfer of data (a digital bit stream) over a point-to-point or point-to-multipoint communication channel. 

•While analog transmission is the transfer of a continuously varying analog signal, digital communications is the transfer of discrete messages.

BASIC DATA TRANSMISSION CONCEPT•ANALOG AND DIGITAL SIGNALLING•DATA MODULATION•SIMPLEX,HALF-DUPLEX AND FULL-

DUPLEX•MULTIPLEXING•POINT-TO-POINT TRANSMISSION•BROADCAST TRANSMISSION•THROUGHPUT•BANDWITH

ANALOG SIGNALLING

•Analog signal is a continuous signal that contains time-varying quantities.

•Using of continuous signals to represent information/data.

•An analog signal can be used to measure changes in some physical phenomena such as light, sound, pressure, or temperature.

ANALOG SIGNALLING

•An analog signal is characterized by four fundamental properties:

i. Amplitude ii. Frequency iii. Wavelengthiv. Phase.

DIGITAL SIGNALLING

• A physical signal that is a representation of a sequence of discrete values.

•A pulse of positive voltage represents a ‘1’. A pulse of zero voltage represents a ‘0’.

•Every pulse in the digital signal is called a binary digit, or bit.

DIGITAL SIGNALLING

•Using of discrete signals to represent information/data.

•Number, letters or icons are all examples of digital signal.

Advantage:▫more reliable than analog transmission▫noise affects digital transmission less

severely

DIFFERENCES BETWEEN ANALOG AND DIGITAL SIGNALS

ANALOG DIGITAL

1. Analog signal are continuous.

2. Analog signal is continuously variable.

3. The primary disadvantage of an analog signal is noise.

4. Sound waves are a continuous wave and as such are analog in the real world.

5. Analog signal required lesser bandwidth capacity than digital capacity.

1. Digital signal is discrete.2. Digital signal are based on

0's and 1's.3. Noise is much easier to

filter out of a digital signal.4. Most computers used such

as the PC work using digital signals.

5. Digital signal required greater bandwidth capacity than analog signals.

DATA MODULATION

•Modulation is the process of conveying a message signal, for example a digital bit stream or an analog audio signal, inside another signal that can be physically transmitted.

•The data signals issued by your computer must be converted into analog form before they get to the media transmission.

DATA MODULATION

They must be converted back into digital form when they arrive at the ISP’s access server.

A modem (modulator/demodulator) accomplishes this translation.

Modulates digital signals into analog signals at the transmitting end, then demodulates analog signals into digital signals at the receiving end.

DATA MODULATION

Is a technology used to modify analog signals to make them suitable for carrying data over a communication media.

In modulation, a simple wave, called a carrier wave, is combined with another analog signal to produce a unique signal that gets transmitted from one node to another.

The carrier wave has preset properties (including frequency, amplitude, and phase)

TRANSMISSION MODE

• The transmission is characterised by:

1. the direction of the exchanges

2. the transmission mode: the number of bits sent simultaneously

3. synchronization between the transmitter and receiver

TRANSMISSION MODE

•SIMPLEX

•HALF-DUPLEX

•FULL-DUPLEX

SIMPLEX

•Simplex refers to one-way communications where one party is the transmitter and the other is the receiver.

• Exp: Radio

HALF-DUPLEX

•A connection in which the data flows in one direction or the other, but not both at the same time.

• Exp: Walkie-talkie

FULL-DUPLEX

• A connection in which the data flow in both directions simultaneously.

•Can transmit and receive at the same time

• Exp: Telephone.

MULTIPLEXING

• A form of transmission that allows multiple signals to travel simultaneously over one medium.

• Process of transmitting two or more individual signals over a common path.

• A device that performs the multiplexing is called a multiplexer (MUX), and a device that performs the reverse process is called a demultiplexer (DEMUX)

FREQUENCY DIVISION MULTIPLEXING

•An analog technique.

•Analog multiplexing technique that combines signals by using the different carrier frequencies.

TIME DIVISION MULTIPLEXING

•The digital technique.

•A digital multiplexing technique to combine data by using the time slot.

•The process of dividing up one communication time slot into smaller time slots.

WAVELENGTH-DIVISION MULTIPLEXING

•The process by which multiple channels of information carried over the same fiber, each using an individual wavelength.

•Using two wavelength that utilizes 1320nm and the other 1550nm.

RELATIONSHIP BETWEEN NODES

•POINT-TO-POINT TRANSMISSION

•BROADCAST TRANSMISSION

•THROUGHPUT

•BANDWIDTH

POINT-TO-POINT TRANSMISSION

• Carrying a communication signal between two locations without branching to other locations.

• Refers to a communications connection between two nodes or endpoints.(one transmitter and one receiver)

• An example is a telephone call, in which one telephone is connected with one other, and what is said by one caller can only be heard by the other.

BROADCAST TRANSMISSION

•Sending the same signal to many different places,like a television broadcasting station.(one transmitter and multiple receiver).

THROUGHPUT

• the average rate of successful message delivery over a communication channel.

•This data may be delivered over a physical or logical link, or pass through a certain network node.

•The throughput is usually measured in bits per second (bit/s or bps), and sometimes in data packets per second or data packets per time slot.

BANDWIDTH

•Measure of the difference between the highest and lowest frequencies that a medium can transmit.

IDENTIFY THE COMMON TRANSMISSION FLAWS AFFECTING DATA:

Noise

Attenuation

Latency

TRANSMISSION FLAWS: NOISE

•Electromagnetic interference (EMI): waves emanating from electrical devices or cables

•Radiofrequency interference (RFI): electromagnetic interference caused by radiowaves

•Crosstalk: signal traveling on a wire or cable infringes on signal traveling over adjacent wire or cable

TRANSMISSION FLAWS: NOISE

•Certain amount of signal noise is unavoidable

•All forms of noise measured in decibels (dB)

TRANSMISSION FLAWS: ATTENUATION

The strength of a signal falls off with distance over any transmission medium

Problems are dealt by the use of amplifiers or repeaters.

TRANSMISSION FLAWS: ATTENUATION

A device that regenerates a analog signal is called a amplifier.

Analog signals pass through an amplifier, an electronic device that increases the voltage, or strength, of the signals.

A device that regenerates a digital signal is called a repeater.

An analog signal distorted by noise and then amplified

A digital signal distorted by noise and then repeated

TRANSMISSION FLAWS: LATENCY

•Delay between transmission and receipt of a signal▫Many possible causes:

Cable length Intervening connectivity device (e.g.,

modems and routers)

•Round trip time (RTT): Time for packets to go from sender to receiver and back

TRANSMISSION FLAWS: LATENCY

•Cabling rated for maximum number of connected network segments

•Transmission methods assigned maximum segment lengths