Principles of Communication - Introduction
The word communication comes from the Latin word "commūnicāre", which means "to share". Communication is the basic step in the exchange of information.
For example, a baby in a cradle communicates by shouting that she needs her mother. A cow mooses loudly when in danger. A person communicates using a language. Communication is the bridge to be shared.
Communication can be defined as the process of exchanging information by means such as words, actions, signs, etc., between two or several people .
Need for communication
For every living being, while coexisting, there is a need for an exchange of information. Whenever a need for the exchange of information arises, means of communication should exist. Although the means of communication can be gestures, signs, dEither symbols or a language, the need for communication is inevitable.
Language and gestures play an important role in human communication, while sounds and actions are important for animal communication. However, when a message is to be transmitted, a communication must be established.
Parts of the communication system
Any system that provides communication, consists of the three important and basic parts as shown in the following figure.
L ' Sender is the person sending a message. It may be a transmitting station from which the signal is transmitted.
The Channel is the means by which message signals travel to reach the destination.
The recipient is the person who receives the message. It may be a message station.reception where the transmitted signal is received.
What is a signal?
Co The transmission of information by certain means such as gestures, sounds, actions, etc., can be qualified as signaling . Thus, a signal can be a source of energy that transmits information . This signal helps to establish communication between a transmitter and a receiver.
An electrical pulse or an electromagnetic wave that travels a distance to transmit a message can be termed a signal in communication systems.
Depending on their characteristics, signals are mainly classified into two types: analog and digital. The analog and digital signals are then classified, as shown in the following figure.
A continuous signal varying in time, which represents a quantityvarying in time, may be referred to as an analog signal . This signal continues to vary over time, depending on the instantaneous values of the quantity, which represents it.
Consider, a tap that fills a tank with a capacity of 100 liters in one hour (6 am to 7 am). The filling portion of the reservoir varies depending on the variable weather. This means that after 15 minutes (6.15 am), a quarter of the tank is full, while at 6.45 am, 3/4 of the tank is full.
If you try to plot the different portions of water in the tank, depending on the varying weather, it would look like the following figure.
As the resultant shown in this image varies (increases) with time, this time varying quantity can be understood as an analog quantity. The signal which represents this condition with an inclined line in the figure, isan Analog signal . Communication based on analog signals and analog values is called Analog communication .
A signal which is inherently discrete or which is non-continuous in form may be referred to as a digital signal . This signal has individual values, noted separately, which are not based on the previous values, as if they were derived at that particular time.
Consider a classroom to have 20 students. If their attendance in a week is plotted, it would look like the following figure.
In this figure, the values are shown separately. For example, class attendance on Wednesday is 20 while Saturday is 15. These values can be viewed individually and separately or discretely, so they are called values discreet .
Binary digits that only have 1s and 0s are usually called numeric values . Therefore, signals that represent 1s and 0s are also called digital signals . Communication based on digital signals and digital values is called Digital communication .
Any analog or digital signal, which repeats its pattern over a period of time, is called a periodic signal . This signal has its pattern continued over and over and is easy to guess or calculate.
If we consider a machine in an industry, the process that takes place one after another is a continuous and repeated procedure. For example, sourcing and grading raw material, processing material in batches, packing a load of products one after another, etc., follow a certain process.re several times.
Such a process, whether considered analog or digital, can be graphically represented as follows.
Any analog or digital signal, which does not repeat its pattern over a period of time, is ca lled as Aperiodic signal . This signal has its pattern continued but the pattern is not repeated and is not so easy to assume or calculate.
A person 's daily routine, if considered, consists of many types of works that take different time intervals for different works. The time interval or work is not repeated not continuously. For example, a person will not brush their teeth continuously from morning to night, this too with the same period.
Such a process, whether it is considered analog or digital, can be representedgraphically as follows.
In general, the signals that are used in communication systems are analog in nature, which are transmitted to analog or converted to digital and then transmitted, as needed.
But In order for a signal to be transmitted remotely, without the effect of any external interference or addition of noise and without fading, it must undergo a process called Modulation , which is discussed in the next chapter.