Difference between Analog and Digital

Updated on February 13, 2017

We often hear the words analog and digital when referring to objects that we use. We have analog and digital watches, film and digital cameras, VHS (Video Home System) and DVD (Digital Video Disc). How is analog different from digital? Read on and we’ll provide you a comprehensive view on the differences between analog and digital.

Definitions

Analog
An analog wall clock

Analog comes from the Greek words ana and logos, which mean “according to” and “relationship,” respectively. Together, they can mean “proportional.” Analog may refer to analog signal, data, medium, device or technology.

A simple example of an analog measurement is taking a temperature with a mercury thermometer. Temperature is represented as the distance the mercury travels along the thermometer.

Analog Signals or Data

Analog signals are continuous-time signals for which the variable component is replaced with another time-varying quantity proportionate to the original signal. This is usually done to facilitate transmission or storage of the signal or data. An example is converting sound, such as voice or music, into electrical signals that can be transmitted over wires. The same audio signals can be transmitted over the air when converted to radio signals.

Analog Media

Analog media refers to the vehicle of transmission or storage of the analog data. Given the example earlier, the analog medium can refer to the wires and cables for the transmission, and phonograph or magnetic tape for storage. Among phonographs, the audio data is stored as grooves of varying fluctuations corresponding to the frequency and volume of original sound. In magnetic tapes, iron or iron oxide particles on the moving tape are magnetized to contain the analog data. When it comes to analog cameras, the medium is the film. Film contain photosensitive particles which change its property depending on the amount of light it is exposed to.

Analog Device or Technology

Analog devices refer to the equipment that converts the source signal into analog signal and back to the original nature of the source signal. In the example of the conversion of sound, the analog devices are the microphone and the speaker as well as the electronic equipment that integrates these devices and process the signal. Timepieces such as watches and clocks, which tell time with the continuous movement of hour, minute, and second hands are also considered to be analog devices. Other analog devices are film cameras, land telephones, radios, and cathode ray tube television.

Digital
A digital desk clock

Digital refers to digital signal, data, media, device, or technology. It comes from the Latin word digitus meaning “finger,” which we often use for counting discrete numbers. In today’s technology, this pertains to binary digits (1 and 0), in contrast to analog, which can take on any value in between.

Digital Signals or Data

Digital signals are discrete (non-continuous) signals that carry information usually coming from analog sources. The way it is done is with the use of analog-to-digital converters (ADC). The ADC takes samples of the analog signal at regular intervals and converts the sampled values into their binary equivalent. A sampled value of 50, for example, is represented by 110010 in binary digits, and a value of 58 will be 111010 if in binary. These signals will either be the presence or absence of signals on the medium, accomplished by turning electronic switches on and off.

Digital Media, Devices, and Technology

Digital signals are transmitted via various digital media such as co-axial cables, fiber optic cables, or transmitted as radio waves over the air. The data may be stored in digital magnetic tapes, compact discs or DVDs, hard disks or solid state disks. Digital-to-analog converters (DAC) are then used to convert these back to analog signals when we are ready to use them.

Examples of digital devices are digital clocks, digital cameras, smart phones and computers.

Analog vs Digital

So what is the difference between analog and digital?

Analog is continuous, while digital is discrete. In other words, while analog can take on any value, digital uses whole numbers expressed in binary form (1 and 0).

In analog systems, the smallest amount of interfering noise alters the signal, whereas in digital, it would take a large amount of noise for the system to interpret a 0 as a 1 or vice versa. In digital systems, data is better preserved against noises in the environment.

The standard analog copper wires can handle only one telephone call whereas the use of fiber optic cables may handle 3000 telephone calls at once by utilizing lasers as the mode of transmission. Digital media can also handle more data than their analog counterpart.

Analog signals need to be converted prior to being processed with computers compared to signals in digital form, which can be readily processed. This makes video, photo, and audio editing available to almost everyone.

Comparison Chart

AnalogDigital
ContinuousDiscrete, expressed in 1’s and 0’s
Easily altered by external noisePreserved better against external noise
Analog media handles relatively less data than digital mediaCan handle more data than analog media
Needs conversion before it can processed by computersSignals are easily processed by computers

Video

Check out this video to further understand the differences between analog and digital.