Elements of a Communication System

Introduction

Communication may be defined as the transfer of information from one place to another via a sequence of procedures, or it can be defined as the communication of information itself. For communication to be effective, both the sender and the receiver must communicate in the same language. Every living organism on the planet is confronted with the need to continually transmit and receive information from others in the surrounding environment. All throughout history, human beings have made an ongoing effort to increase the quality of communication with other human beings. From prehistoric to contemporary times, the methods and languages used in communication have continued to evolve and satisfy the increasing demands in terms of complexity and the speed of information transmission.

A speech signal, computer data, or an image may be used to convey the message. The signals have a variety of frequencies that vary from one another. The sort of communication system required is determined by the range of frequencies deemed vital for the communication process to communicate a specific signal. This article examines the critical components of a communication system, the many kinds of communication systems, and the signal bandwidth.

Parts and Subsystems of a Communication System

There are three critical components to every communication system. The transmitter, the channel, and the receiver. The block diagram of a general-purpose communication system is shown in the figure below.

Basic components of communication system

The information can be sent over a communication system from either a person or a machine. A transmitter is positioned at one location, and a receiver is located at another location, with the channel serving as a medium between the two locations. It is the message signal that originates from the source, and it is this signal used to feed into the transmitter.

In general, the transmitter’s primary function is to transform the message signal created by the source of information into a form that can be sent across the channel. The signals that are conveyed are referred to as transmitted signals. Transducers transform nonelectrical signals into electrical signals when the message signal from the source of information is nonelectrical.

The physical media that links the transmitter and receiver (whether wired or wireless) is the channel. It is possible that the broadcast signal may be warped due to its imperfection, and that some noise will be added to the transmitted signal as it propagates.

An in-depth examination of the components of the communication system, Information is the concept or message that is being given. It is also known as knowledge. The message may consist of a single message or a series of messages. The message might take the form of a symbol, a code, a sequence of words, or any other predetermined unit.

A transducer, modulator, amplifier, and transmitting antenna are all transmitter components in radio transmission. Transducers are also known as transmitters.

Note:

• A transducer is an electronic device that transforms sound waves into electric signals.
• An audio modulator is a device that combines an electric audio signal and a high-frequency radio wave.
• The modulated signal is amplified by the amplifier, which increases its power.
• With the help of an antenna, the signal is broadcast into the surrounding space.
• An in-depth examination of the components of the communication system

It is the responsibility of the communication channel to transport the modulated signal from the transmitter to the receiver. Communication channel definition: The communication channel is sometimes referred to as a transmission link or a medium of transmission.

In radio communications, the phrase “channel” refers to the frequency band that has been assigned to a particular broadcast or service.

Basic elements of communication system

There are different kinds of communication systems based on the type of modulation used:

(i) Amplitude modulation is one kind of modulation (AM)

(ii) Frequency modulation is another kind of modulation (FM)

(iii) Phase modulation is a kind of modulation (PM)

(iv) Pulse amplitude modulation is a kind of modulation (PAM)

Modulation

Because digital and analog signals have a low frequency, they cannot be sent across long distances. These signals need the use of a carrier. Carrier waves or high-frequency signals are the terms used to describe these carriers. Modulation is the placing of a low frequency (LF) signal on top of a high frequency (HF) signal and is defined as follows:

Modulation is required because the sound wave (20 Hz to 20 kHz) cannot be transferred straight from one location to another due to the following reasons:

It is recommended that the transmitting and receiving antennas have a height similar to a quarter of the frequency’s wavelength to provide efficient emission and reception. It is 5000 m for 15 kHz (which is much too huge) and 75 m for 1MHz (also far too large).

When the signal frequency to be sent is less than 15 Hz, the amount of energy emitted by an antenna is almost non-existent.

Signal detection: Because all audible signals fall within a frequency range of 20 Hz to 20 kHz, the signals from all sources stay densely mixed in the air. It will be difficult to distinguish or identify the broadcast signal at the receiving station, since it would be distorted.

Consequently, modulation is required for a low-frequency signal when it is transferred to a remote location to prevent the information from being lost in the transmission process and for accurate identification of a signal while maintaining the antenna’s height to a minimum.

Amplitude Modulation

This procedure, known as amplitude modulation (AM), is defined as “the process in which the amplitude of the modulated wave is adjusted in line with the amplitude of the modulating wave.” In AM, the carrier wave’s frequency remains constant throughout the transmission.

Conclusion

The modulation factor determines the strength and quality of the transmitted signal.

A straight conductor of the length l=λ2 of radio signals transmitted or received is called a Hertz antenna. The Marconi antenna is a straight conductor of length  l=λ4.

In a digital signal, information is carried by the pattern of pulses and not by the shape of pulses.

The three important elements in a communication system are Transmitter, Channel, and Receiver.

The transmitter converts the message signal produced by the source of information into a suitable form for transmission.