Communication Systems

What is a Communication System?

The communication system is a system model that describes a communication exchange between two stations, transmitter, and receiver. Signals or information passes from source to destination through a channel. It represents a way in which the signal uses it to move from a source toward its destination. To transmit signals in a communication system, it should first be processed by beginning from signal representation, to signal shaping until encoding and modulation. After the transmitted signal is prepared, it is passed to the transmission line of the channel. Due to signal crossing this media, it is faced with many impairments like noise, attenuation, and distortion.

[Image will be Uploaded Soon]

Types of Communication Systems

Based on physical infrastructure there are two types of communication systems:

  • Line communication systems

  • Radio Communication systems

There is a physical link, called a hardwire channel between the transmitter and the receiver inline communication systems. 

Signal specifications that are used to decide the type of communication system are:

  • Nature of the baseband or information signal.

  • Nature of the transmitted signal.

According to the nature of the baseband signal, the communication systems are:

  • Analog communication systems

  • Digital communication systems

Based on the nature of the transmitted signal, the baseband signal can either be transmitted as it is without modulation or through a carrier signal with modulation. The two systems can then be categorized as:

  • Baseband communication system

  • Carrier communication system

The four types of the communication system based on the signal specification are:

  • Analog communication systems

  • Digital communication systems

  • Baseband communication systems

  • Carrier communication systems

Out of four, a minimum of two types is needed to specify any communication system. Thus, two groups are formed consisting of each of the two types such that at least one of the types from each group is necessarily required to specify a communication system. These groups can be formed as:

  • Analog/digital communication systems

  • Baseband/carrier communication systems

To completely define any communication system, four out of the eight types are required. If anyone type is missing, then the description of the communication system will be incomplete.

Terms Used in Communication Systems

1. Signal

A signal is that information that has been converted into a digital format. 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. 

2. Communication Channel

A communication channel is a medium by which a signal travels.

3. Transducer

The device used to convert one form of energy into another form is a transducer.

4. Receiver

A receiver is a device that receives the signals sent/ transmitted by the senders and decodes them into a form that is understandable by humans. 

5. Attenuation

Attenuation is the reduction in the strength of analog or digital signal as it is transmitted over a communication medium. 

6. Amplitude

An amplitude of the signal refers to the strength of the signal.

7. Amplification

Amplification is the process to strengthen the amplitude of the signals using an electronic circuit.

8. Bandwidth

Bandwidth explains the range of frequency over which a signal has been transmitted.

9. Modulation

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)

10. Demodulation

Demodulation takes a modulated signal and then extracts the original message from it.

11. Repeater

The repeater extends the range of communication systems by amplifying the signals. 

12. Noise

Any electrical signal which interferes with an information signal is called noise.

Did You Know?

  • Communication Is Related To Every Human Activity.

  • Communication in Organization Flows in Various Patterns.

  • Communication Is Media or Channel Based

  • 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.

FAQ (Frequently Asked Questions)

1. What is a Duplex Communication System?

The system that has two connected devices that are able to communicate with each other in both the directions is called a duplex communication. The duplex term is used while describing communication between two parties or devices. Duplex systems are employed in almost all communications networks. An Antenna is basically a small length of a qwerty conductor that is used to radiate or receive electromagnetic waves. It acts as a conversion device. At its transmitting end, it can convert a current of high frequency into electromagnetic waves. At the receiving end, it transforms electromagnetic waves into electrical signals that are fed into the input of the receiver. 

2. What is a Communication Channel? Explain in Detail.

A communication channel is a medium by which a signal travels. There are two types of media by which electrical signals travel - guided and unguided. Guided media is a medium that is directed from transmitter to receiver by means of connecting cables. Guided media includes coaxial cables, telephone wire, twisted-pairs, etc. The other type of media is unguided media referring to any communication channel which creates space between the transmitter and receiver. For radio communication, the air is the only medium between the transmitter and the receiver. Communication channels include everything from the vacuum of space to solid pieces of metal.