1. Introduction to Communication Systems (CNET - 222)
Dr. Mohammed Abdul Gaffar Ali
Department of Computer Networks
College of CS&IS
Jazan University, Jazan.

2. Communication system Blocks
Chapter 1 Introduction
Communications
Communication system Blocks
Need for modulation
External Noise
Internal Noise

3. Communication Definition.
communications refers to the sending, receiving and processing of information by electronic means.

4. Blocks Of Communication

5. Modulation
Modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a modulating signal that contains information to be transmitted

6. Need For Modulation.
The Height of Antenna is inversely proportional to the Frequency ,Hence to transmit low frequency signal the required height of antenna will be very high.
High Frequency signal with power can travel long distances.
When we use modulation the channel capacity will also increase.
Noise can be controlled more when using modulation.

7. Unwanted interfering Signal.
Noise
Definition
Unwanted interfering Signal. OR
Noise may be defined, in electrical terms, as any unwanted introduction of energy tending to interfere with the proper reception and reproduction of transmitted signals.

8. Types of Noise External Noise. Internal Noise.
Depending on the type of source Noise can be classified in to two types.
External Noise.
Internal Noise.

9. Extraterrestrial Noise
External Noise
If the source of the Noise is from outside of circuit then it is called External Noise.
Examples of External noise are:-
Atmospheric Noise
Extraterrestrial Noise
Industrial Noise.

10. Internal Noise
If the source of the Noise is from inside the circuit then it is called Internal Noise.
Examples of Internal noise are:-
Thermal Agitation Noise
Shot Noise(Due to components)
Transit Time Noise.

11. Defined As

13. Definition It is the ratio of the input SNR on the output SNR.

14. Thank You