Difference between Analog and Digital Signals

In this article, we will study the important differences between analog signals and digital signals. In communication engineering, a signal is defined as an electrical quantity like current, voltage, or an electromagnetic wave that is used to transfer information from one point to another.

Based on nature, signals are classified into the following two types:

• Analog Signals
• Digital Signals

Let’s start with the basic introduction of analog and digital signals individually.

Introduction to Analog Signals

An analog signal is one that has a continuous-time value and is represented as a continuously varying waveform against the time axis. In other words, an analog signal is a type of signal that has a definite value at every instant of time and is expressed as a continuous-time function.

Examples of analog signals include alternating voltage or current, pressure, speed, velocity, etc.

An electronic system that uses analog signals to work or transmit information is termed an analog system. A common example of an analog system is a sound system.

In the case of an analog signal, the values of the signal are defined at every instant of time, called the instantaneous value of the signal.

Analog signals are considered natural signals and they can be processed and transmitted at very high speeds. However, analog signals are highly sensitive to noise and distortion during transmission. Also, they have another major drawback that is the signal quality degrades with increasing distance.

Introduction to Digital Signals

A signal defined at discrete instants of time and can take only two values namely ‘on’ and ‘off’ is called a digital signal. In other words, a digital signal is a discontinuous function of time.

Digital signals can have their values defined at discrete (individual) instants of time only. Digital signals are expressed in the form of strings of bits (binary digits). They have only two values, i.e. HIGH (binary 1) and LOW (binary 0).

Examples of digital signals are data signals transmitted over the internet and digital computer networks, ethernet signals, data stored in hard disk, and more.

An electronic system that can process digital signals is referred to as a digital system.

Our laptops, desktops, smartphones, etc. are practical examples of digital systems.

Today, digital signals are widely being used in data communication and information processing due to their high immunity against noise and low-cost data processing and transmission.

After getting a basic idea about analog and digital signals, let us now discuss their significant differences.

Difference between Analog and Digital Signals

The important differences between analog and digital signals are given in the following table:

Key	Analog Signal	Digital Signal
Nature	Analog signals are continuous time-varying signals.	Digital signals are discontinuous time signals.
Representation	Analog signals are represented as a continuous waveform against the time axis.	Digital signals are represented as a string of binary digits (bits).
Noise immunity	Analog signals are more sensitive to noise than digital signals.	Digital signals have high immunity to noise.
Accuracy	Analog signals are less accurate due to high susceptibility to noise.	Digital signals are more accurate due to low susceptibility to noise.
Troubleshooting	Analog signals are complex to troubleshoot.	Digital signals are easier to troubleshoot than analog signals.
Transmission efficiency	Analog signals have lower transmission efficiency as they can be affected by external factors during transmission.	Digital signals have higher transmission efficiency.
Bandwidth capability	Analog signals have lower bandwidth capabilities.	Digital signals have higher bandwidth capabilities.
Applications	Analog signals are mainly used for audio and video signal transmission.	Digital signals are mainly used for computing, data communication, internet communication, etc.
Examples	Common examples of analog signals are voice signals, alternating current and voltage, speed, pressure, etc.	Common examples of digital signals are internet signals, data stored in computer memory, switching signals, etc.

Hence, this is all about analog and digital signals and their important differences. Analog and digital signals are quite important in the field of electronics and communication engineering, as they allow to transmission of information from one point to another. Today, analog and digital signals are being used to connect the world together, hence they have significant importance in our lives.