Question

Differentiate between analog signal and digital signal with diagrams.

Answer 1

Hint: Analog signal and digital signals are both two different ways of communicating in a communication channel, based on the type of signal that carries the data. Digital is discrete in nature, whereas analog is continuous.

Complete step-by-step answer:
In communication, a signal implies a time-varying electrical signal obtained by transforming the original signal with the help of a suitable transducer. It is a single-valued function of time that conveys the information.
The message signals are of two types:
Analog Signal
Digital Signal
ANALOG SIGNAL
A signal in which the current or voltage varies continuously with time is called an analog signal. As shown in the figure below, a sinusoidally varying alternating value with time is the simplest analog signal representation.

Analog communication makes use of analog electronic circuits and analog signals in such a way that the output voltage varies continuously in accordance with the input voltage. For example, telegraphy, telex, TV network, etc.
The analog signals are less reliable due to its many valued outputs. So it is rarely used in modern communication.

DIGITAL SIGNAL
A signal in which current or voltage has only two discrete values is called a digital signal. A digital signal can take only two values 1 and 0 which are also known as high or low values.
The following figure shows a square wave signal:

Thus the digitals are in the form of pulses of equal level. Unlike analog signals, digital signals can be used as effective commands. The low in a digital signal refers to an open circuit which is also known as no space, while high or 1 refers to a closed circuit which is known as yes or mark.

The following table gives the pointwise difference between analog and digital signals:

ANALOG SIGNAL	DIGITAL SIGNAL
Analog signals are continuous signals	Digital signals have a discrete value of 1 or 0
Analyses of analog signals are very difficult.	Analyses of digital signals are comparatively easier.
The bandwidth of these signals is low.	The bandwidth of these signals is high.
They don’t offer a flexible implementation.	They offer a flexible implementation.
The processing of these signals can be done in real-time.	The processing of these signals cannot be done in real-time.
They don’t offer a fixed range	These offer a finite value of either 1 or 0

Note: Both digital and analog signals have their own pros and cons. These are used according to the need of the communication channel. Analog signals are used in temperature sensors, FM radio signals, and photocells. Digital signals are used in computers, modern forms of communication, etc.