A Communication system's goal is to produce data-carrying signals from a source in one location to a user destination in another. Communication systems may be classified into two categories based on the type of signal processing used on the information-carrying signal. They are:

1) Analog Communication System

2) Digital Communication System

The information-carrying analog signal in an analog communication system is constantly changing in both amplitude and time. It is directly used to change the amplitude, phase, or frequency of a high-frequency sinusoidal carrier wave. Analog signals include speech, video, temperature, and pressure signals, among others.

The information-carrying digital signal is processed in a Digital Communication system so that it may be represented by a series of binary digits (discrete messages). Then it's used to toggle between ON and OFF any aspect of a high-frequency sinusoidal carrier wave, such as amplitude, phase, or frequency. If the input message signal is analog, sampling, quantizing, and encoding are used to transform it to digital form. Digital signals include computer data and telegraph signals. A digital communication system's most distinguishing feature is that it works with a limited number of distinct messages.

Due to the ever-increasing demand for data communication, digital communication technologies are becoming more appealing. Because digital transmission provides data processing choices and flexibility that analog transmission does not. Furthermore, advances in digital technology have resulted in the creation of increasingly powerful microprocessors, larger and larger memory devices, and a growing number of programmable logic devices. Due to the widespread availability of these devices, designing digital communication networks has become much easier.

ADVANTAGES OF DIGITAL COMMUNICATION OVER ANALOG COMMUNICATION

1. "Regenerative repeaters" are used to provide a robust, error-free signal at a high power level.

2. Compared to analogue circuits, digital circuits are less prone to distortion and interference.

3. Through error identification and repair, digital systems may achieve extremely low error rates and great signal fidelity.

4. Compared to analogue circuits, digital circuits are more dependable and can be created at a cheaper cost.

5. Compared to analogue circuits, digital hardware allows for more flexibility in implementation.

6. Using Time Division Multiplexing (TDM) to combine digital signals is easier than using Frequency Division Multiplexing to combine analogue signals (FDM).

7. In transmission and switching, different types of digital signals (data, telegraph, telephone, television) can be treated as identical signals - a bit is a bit.

8. Signal processing functions that prevent against interference and jamming, as well as encryption and privacy, are naturally suited to digital approaches.

9. In addition, a lot of data is sent from one computer to another, or from digital instruments or terminals to computers. Digital communication channels are, of course, ideally suited to such digital terminations.

10. Voice, data, and video storage and retrieval at intermediate locations (in the transmission channel) is simple and economical in terms of storage space.

11. Signal and image processing techniques, such as speech and image signal compression, are easy to process.

12. Adaptive equalisation is a viable option.

13. To preserve high levels of communication confidentiality, very sophisticated encryption and decryption methods are available for digital data.

14. The availability of powerful microprocessors, bigger memory devices, and a huge number of programmable logic devices has simplified the design of digital communication systems.

15. The switching theory, a mathematical theory of logic circuits, is a particularly useful perception in digital communication.

16. In digital circuits, noise, temperature, and parameter fluctuations have a minimal influence.

DISADVANTAGES OF DIGITAL COMMUNICATION OVER ANALOG COMMUNICATION

1. When compared to analogue systems, digital systems require a lot of signal processing.

2. Digital systems must devote a large portion of their energy to varying levels of synchronisation.

3. In digital communication systems, non-graceful degradation can occur when the signal-to-noise ratio falls below a given threshold, causing the quality of service to abruptly transition from excellent to bad.

4. Compared to analogue communication systems, digital communication systems require higher bandwidth.

5. When compared to analogue components, digital components use greater power.