ECE-321 INTRODUCTION 2 TELECOMMUNICATION · 2014. 2. 3. · INTRODUCTION 2 TELECOMMUNICATION . I...

I – term 2013-2014 INTRO 2 TELECOM (EE321)

Prepared by : Dr. Lotfi LADHAR

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ECE-321

INTRODUCTION 2 TELECOMMUNICATION



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CONTENT

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RF wave propagation.

Antennas for HF, VHF, UHF and

microwaves.

Noise in Communication Systems.

Link Budget Analysis.

Fundamentals of Radar Systems.

Fundamentals of Satellite Communications.

Fundamentals of Wireless Communications.



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Weekly Calendar

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Weekly Calendar of Lectures

Week Topics Remarks

1, 2 RF wave propagation

2, 3 Antennas for HF, VHF, UHF and microwaves

4 Noise in Communication Systems

5 Link Budget Analysis

6, 7, 8 Fundamentals of Radar Systems

9, 10, 11 Fundamentals of Satellite Communications

12 -15 Fundamentals of Wireless Communications

Final Exam



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MARK DISTRIBUTION

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LAB(SIM) LAB(EXP) HWs Attendance+ Participation Quiz Midterm Final Exam

10 10 10 10 10 20 30

Mark Distribution EE321



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CHAP1

COMMUNICATION SYSTEM



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source: originates a message

transmitter: converts the message into a signal that can be transmitted over a channel

Channel: transport of the signal over a certain medium (e.g. wire, optical fiber or a radio link)

Receiver: converts the received signal back into a readable message

destination: end user

I-THE BLOCK DIAGRAM



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Sources of Information

1. Voice Microphone

2. Image Camera

3. Data Computer

Electrical

Signal

Types of Channels

1. Free space wireless comm.

2. Cables

3. Optical fibers Wire Comm.



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2) Transmitter : Modifies the baseband signal for efficient

transmision. The transmitter consists on preamphizer, sampler,

Encoder, modulator and Amplifier



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4) Transmission Medium Channel

Pair of copper wires

Coaxial cable

Radio link

Light in optical fiber

Light in air

Waveguide



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1



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II Transmission Impairments

The transmission signal is subjected to the following

undesirable effects created by the transmission channel



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1. Noise

Is defined as random and unpredictable electrical signals

produced by natural processes both internal and external

to the system



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External Noise

Man-made noise generated by contact

switches

Automobile ignition Radiation

Flurescent lights

Electrical Storms

Solar radiation



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Internal Noise

Thermal motion of electrons in conductors

Random Emission diffusion or recombination of

charged carriers in electronic devices



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Signal to Noise Ratio (SNR)

Signal Power

By definition SNR = -------------------------

Noise Power



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2. Attenuation

Attenuation is defined as the reduction in the signal strength

as it travels along the transmission medium. It is also called

“ Transmission Loss”.

Attenuation is directly proportional to distance and frequecy

Rain and snow also increases attenuation where the atmosphere

used as a transmission medium.



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3. Distortion

The waveform perturbation caused by the imperfect response

of the system is called distortion.



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4. Interference

Interference results from the combination of or two or more signals

In the same frequency band.

As a result of interference, the signals sometimes add up to create a

more powerful signal and sometimes canal each other to create a

weaker signal



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5) Receiver Reponses the signal from the channel by undoing

the signal modification made at the transmitter and the channel.

The receiver may consists on a Demodulator, a decoder a filter

a deemphasizer and an amplifier



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6) destination The unit to which the message is communicated.

It can be the user , a computer .

The output signal is similar to the original input message.m



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III -TRANSMISSION MODES

1. Baseband Transmission Mode

2. Passband (BroadBand)Transmission Mode



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1. Baseband Transmission Mode



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2. Passband (BroadBand)Transmission Mode



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IV MODULATION Baseband signal produced by various information sources

are not always suitable for direct transmission over a given channel .

Therefore the baseband signal is used to modify some parameter

Of a high frequency carrier signal. This process is known as

Modulation

At the receiver the modulated signal must pass through a

receive process called “Demodulation” in order to obtain

The baseband signal



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Questions

TOGETHER WE CAN MAKE THE DIFFERENCE

KNOWLEGE IS A POWER

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ECE-321 INTRODUCTION 2 TELECOMMUNICATION · 2014. 2. 3. · INTRODUCTION 2 TELECOMMUNICATION . I...

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