Difference Between Analog Signal and Digital Signal

The key difference between analog signal and digital signal is that an analog signal is a continuous time signal while a digital signal is a discrete time signal.

A signal carries information from one device to another. In Electrical Engineering, a signal is a fundamental quantity of representing information. In the context of Mathematics, it is a function that conveys information. Analog signal and digital signal are two categorization of signals.

CONTENTS

1. Overview and Key Difference
2. What is Analog Signal
3. What is Digital Signal
4. Relationship Between Analog Signal and Digital Signal
5. Side by Side Comparison – Analog Signal vs Digital Signal in Tabular Form
6. Summary

What is Analog Signal?

An analog signal is a continuous signal, and it changes over time. A sine wave represents this signal where, amplitude, period and frequency are some factors to describe its behavior. The amplitude is the maximum height of the signal. Frequency (f) is the number of cycles per unit of time. Period (T) is the time to complete one cycle (T = 1/f).

It is difficult to analyze an analog signal because it contains a huge number of values. It contains negative values and positive values. Furthermore, the power consumption of an analog instrument is high. Usually, analog signals have a tendency to drop the quality of transmission because of the distortion. A common example of for this signal in our daily life is the human voice.

What is Digital Signal?

A digital signal is a discontinuous and discrete time signal. And it takes the form of a square wave. It represents information in the binary form which is ones (1) and zeros (0). The 1 represents the high values while the 0 represents the low values. These signals do not have negative values like in analog signals.

Using analog signals in communication can cause issues. For example, it is difficult to do long distance communication because of the signal distortion, interference etc. Digital signals are a great solution for this issue. They are less prone to distortion. Therefore, the analog signals are converted into digital signals for clear and accurate communication. Digital phones, computers, and other electronic devices use digital signals.

What is the Relationship Between Analog Signal and Digital Signal?

• A digital signal is a discrete sample of an analog signal within a period of time.

What is the Difference Between Analog Signal and Digital Signal?

Analog Signal vs Digital Signal
An analog signal is a continuous signal that changes over a time period.	A digital signal is a discrete signal that carries information in binary form.
Analyzing
Difficult to analyze	Easier to analyze
Representation
Represented by a sine wave	A square wave represents this signal
Range
Contains a huge number of values that can be either positive or negative	Stays in a finite range. It can have either 0 or 1
Distortion
It has more tendency to get distorted	It has a less tendency to get distorted
Storage
Stores data in a form of wave signal. So it requires an infinite memory.	Stores data in a form of binaries.
Examples
Human speech, instantaneous voltage, and current are few examples of analog signals.	Examples of digital signals are signals in Computers, optical drivers, and digital phones.

Summary – Analog Signal vs Digital Signal

The difference between analog signal and digital signal is that an analog signal is a continuous time signal while a digital signal is a discrete time signal. In brief, digital signals are more reliable and have a fast rate of transmission than the analog signals.

Reference:

Tutorials Point. “Signals and System Introduction.”, Tutorials Point, 8 Jan. 2018. Available here 

Image Courtesy:

1.’Analog signal’By The original uploader was Ivan.Romero (CC BY-SA 3.0) via Commons Wikimedia 
2.’Square wave’ (CC BY-SA 3.0) via Commons Wikimedia