[Physics Class Notes] on Terms Used in Electronic Communication Systems Pdf for Exam

Electronic Communication Systems

Electronic Communication Systems Electronic communications are the transmission, reception, and processing of information between two or more locations with the use of electronic circuits. The basic components of an electronic communications system are the transmitter, communications channel or medium, receiver, and noise. Analog signals (such human voice) or digital signals (binary data) are inputted to the system, processed within the electronic circuits for transmission, then decoded by the receiver. The system is claimed to be reliable and effective only errors are minimized within the process. Examples: Internet, public switched telephone network, intranet and extranet, and television

 

Different Types of Communication Systems

1. Analog

2. Digital

3. Wired (Line communication)

4. Wireless (Space communication)

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Communication System

 

Terms Used In Electronic Communication Systems

1. Information

Message or information is the entity that is to be transmitted. It is often within the sort of audio, video, temperature, picture, pressure, etc.

2. Signal

The single-valued function of time that carries the information. For transmission, the information is converted into an electrical form.

3. Transducer

A device or an arrangement that converts one form of energy to the other. An electrical transducer converts physical variables like pressure, force, temperature into corresponding electrical signal variations. Example: Microphone, Photodetector.

4. Amplifier

The electronic circuit or device that increases the amplitude or the strength of the transmitted signal is named an amplifier. When the signal strength becomes but the specified value, amplification is often done anywhere in between transmitter and receiver. The amplification is provided by a  DC power source.

5. Modulator

As the original message signal can’t be transmitted over an outsized distance due to their low frequency and amplitude, they’re superimposed with high frequency and amplitude waves called carrier waves. This phenomenon of superimposing a message signal with a carrier wave is called modulation. And the resultant wave is a modulated wave which is to be transmitted.

Different Types Of Modulation.

i. Amplitude Modulation (AM)

ii. Frequency Modulation (FM)

iii. Phase Modulation (PM)

6. Transmitter

It is the arrangement that processes the message signal into an appropriate form for transmission and subsequently reception.

7. Antenna

An Antenna is a structure or a device that radiates and receives electromagnetic waves. So, they are used in both transmitters and receivers.

8. Channel

It refers to a physical medium such as wire, cables, space through which the signal is passed from transmitter to the receiver.

9. Noise

Noise is one of the channel imperfections or impairment in the received signal at the destination. External sources include interference, interference generated by natural sources like solar, lightning, or radiation, from automobile generated radiation. The external noise is often minimized and eliminated by the appropriate design of the channel, shielding of cables. Digital transmission external noise is often minimized.

10. Attenuation

Attenuation is a problem caused by the medium. When the signal is propagating for an extended distance through a medium, counting on the length of the medium the initial power decreases. The loss in initial power is directly proportional to the length of the medium. Using amplifiers, the signal power is strengthened or amplified so on reducing attenuation. Digital signals are comparatively less susceptible to attenuation than analog signals.

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Effect of Attenuation

11. Distortion

It is also another type of channel problem. The signal may have frequency and bandwidth different from the transmitted signal when the signal is distorted. The variation in the signal frequency can be linear or nonlinear.

12. Receiver

The message or information from the transmitted signal at the output end of the channel is extracted by an arrangement that is called a receiver and as the original message signal is a receiver it is reproduced in a suitable form.

13. Demodulator

It is the inverse phenomenon of modulation. The process of separation of message signals from the carrier takes place within the demodulator. The information is retrieved from the modulated wave.

14. Repeaters

Repeaters are placed at different locations in between the transmitter and receiver. A repeater receives the transmitted signal, amplifies it, and sends it to the next repeater without distorting the original signal.

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Diagram for Repeaters

 

Fun Facts

• There are around 250 billion emails sent every day. Around 80% of these are spam.

• Around 20 hours of video are uploaded to YouTube every minute. 

• Fiber optics are good because they use less energy and are better for the environment than electrical wires. They are also very resistant to weather. 

• The first telephone pole was built in 1876. 

• There are over 4 billion cell phones within the world and phones that are thrown away every year are over 100 million.

• The first cell phone was invented by a company called Motorola.

• Over 3.8 billion people use the internet, which is 40% of the world’s population.

• The first smiley appeared in 1979, it first looked like this -) then three years later colon was added to it and it took the form of 🙂 this.