Terms used in communication- Attenuation

A communication system is a system of channels that allows information to be exchanged between two or more agents. The communication channel used is when something is exchanged between two or more agents.

Any communication system comprises a sender, a receiver and a channel. Any system can be described by the sender, the receiver and the channel. The most basic term for this concept is “transmitter”, which conveys a message from one point to another. This concept is also used in the context of communication systems such as radio, phones, and the internet. Another term, “receiver”, conveys a message from one point to another.

Communication network:

A communication network is a collection of sending and receiving points linked together by any kind of communication channel. One example of a communication system is Email. It is used for sending and receiving textual, audio, video or other kinds of data. In a communication system, the sending point is called a sender, and the receiving point is called a receiver.

Main components of a communication system:

Communication systems have two main components: (i) a transmitter, which broadcasts the information to be sent and (ii) a receiver, which receives the transmitted information. 

1.Transmitter:

A transmitter is a device that sends a message from one place to another. It consists of a source of electromagnetic energy (e.g., radio waves) and a receiver, which amplifies the energy and turns it into an electrical signal.

2.Receiver:

In a communication system, a receiver is a machine that takes action in response to the received signal. In a wireless communication system, the receiver is the physical device, such as a mobile phone, that is used to receive and decode signals transmitted by a transmitter.

Basic terms used in a communication system:

 A simple communication channel, such as a telephone, a radio, a walkie-talkie, a TV, or a phone, can be used to send signals. Let us discuss the basic terms used in a communication system. 

They are range, attenuation, transducer, amplification, bandwidth, repeater and noise.

In this article, we will discuss all the terms in one-liners but have a main focus on the term ‘attenuation’.

1.Range: 

Range is the distance between the transmitter and the receiver. The range is measured in metres or miles, for example.

2.Attenuation:

Attenuation is the amount of power lost in the communication system. Attenuation is commonly expressed as a percentage.

3.Transducer:

A transducer is a device used for receiving and converting an electrical signal into a mechanical signal and vice versa. 

4.Amplification:

The amplification in the communication system is the ratio between two signals received by the receiver. Basically, the information transfer is called amplification.

5.Bandwidth:

The bandwidth of a communication channel is the bit rate at which data is transmitted through the channel. It is measured in bits per second. The bandwidth of a channel is specified in units of bit per second.

6.Repeater:

In a communication system, a repeater is a tool that receives, amplifies, and sends back an incoming signal. Repeaters are used to amplify signals that may be lost or attenuated due to distance or atmospheric conditions.

7.Noise:

Noise is a source of distortion in any communication system. Noise is a random disturbance in a signal that is unwanted and disturbs the desired signals. 

Attenuation:

Attenuation is a process of change or degradation in a substance. Let’s analyse attenuation in detail and examine its effects on the world around us and how we can use it to our advantage.

Attenuation is a well-known concept in the field of physics. Attenuation is the reduction in amplitude due to the transmission of a wave through a medium. When a signal travels from an object to a receiver, the signal’s amplitude will be reduced by the amount of attenuation.

The signal strength of wireless communication is attenuated in its propagation due to obstacles between the transmitter and receiver. The attenuation’s severity depends on the distance between the transmitter and receiver. In free space (no obstructions), a 1-metre difference in distance between the transmitter and receiver results in transmission power levels of +30 dB and -30 dB, respectively.

When a person sends a radio signal over a few miles, it becomes weaker. This is because the signal spreads out and will eventually lose signal strength. At many frequencies, the effective radiated power of the radio waves falls off as the inverse fourth power of the distance from the transmitter. For example, as the distance is doubled, the power drops by a factor of 16.

Effects of attenuation:

Attenuation leads to a decrease in the strength of the initial signal. This decrease in the strength can mainly occur in two ways: 

1. The signal can be reduced in amplitude 
2. The signal can be delayed. If the first attenuation happens, the signal has less strength because it is less intense, and this is known as amplitude attenuation. Thus, the signal becomes weaker.

The sound barrier is the ultimate effect of attenuation. 

Attenuation causes a reduction in amplitude and, therefore, a decrease in signal strength. This may cause interference with other signals.

Pros and Cons of attenuation:

Pros:

1. The main advantage of attenuation of a communications system is that it makes the communication more secure and reduces the chance of eavesdropping.
2. Attenuation in a communication system reduces the effect of unwanted signals or noise.

Cons:

1. In a communication system, the more attenuation of signals, the slower the rate of information transfer.
2. Attenuation decreases the ability to detect weak signals and increases the error in estimating the original signal. This is a common problem in radio, television and telephone communications.
3. Attenuation may cause a degradation in the overall signal-to-noise ratio. This may adversely affect the reception of the data stream at the receiver and lead to transmission errors.

Attenuation in optical fibre:

In optical fibres, the speed of light is less than the speed at which information can be sent through the fibre. This is called attenuation.

The optical signals are attenuated as they propagate through the fibre. The amount of attenuation depends on the type of fibre, composition of fibre, and signal wavelength.

Conclusion:

In this article, we study an important term attenuation that is used in a communication system. Attenuation is the amount of power lost in the communication system. Attenuation is commonly expressed as a percentage. The signal strength of wireless communication is attenuated in its propagation due to obstacles between the transmitter and receiver. Attenuation causes a reduction in amplitude therefore, signal strength decreases.