Data; Digital and Analogue
Data is represented in either analogue or digital form. They differ from each other as explained below.
Analogue data is represented by the use of continuous variable physical quantities such as voltages. Most natural events of our Earth- temperature, pressure and light- occur and change smoothly and slowly. This can also be shown with an analogue clock where the seconds hands is constantly ticking and the minutes and hours’ hands move respectively. Sound, videos and images as well as many other similar formats are in analogue form.
Sound, videos and images as well as many other similar formats are in analogue form. In the 20th century, virtually every technological device was analogue including seismographs, weight machines and speedometers. Examples of where analogue data is used is the “old-school” thermometers however, more and more devices have become in the form of digital data. Analog signals are continuous and measure physical measurements. They are pulses, usually electrical or optical and are in continuous sine waves. Analogue data is best for audio and video transmission.
On the other hand, “digital data is represented using discrete measurements” in the form of (numerical) digits or numbers. This is exemplified in a digital clock where the time is represented as hours and minutes where the time isn't changing continuously but in certain series of steps. Examples of where digital data is used is in cellphones or in MP3 players. More examples include digital thermometers and blood pressure meters as well as digital bathroom scales which give discrete but fast readings.Numbers, text and other characters and symbols are naturally in a digital form. More examples of where digital data is used in in CDs, DVDs, computers and other similar electronic devices. Digital signals are generated by digital modulation and are in square waves in comparison to the sine waves of an analogue signal wave. Digital data is best suited to computers and digital technology.
Information technology uses digital data forms by using only two numbers; 0 and 1. these digits easily represent the circuits or systems in a computer or digital technological device as being simply on or off. The digit ‘0’ usually electronically represents ‘off’ and ‘1’ represents the ‘on’ state. Each and every on or off digit is called a “bit” which derives from binary digit. It is the smallest unit of data in a computer and when stored in groups of eight, it is called a “byte”. Digital data can be processed in words which are the number of bits processed in a computer at time. When a computer or device takes a bit to another place by moving it, it takes a word at a time. As technology advances, computers are getting faster. Computers can move bits in words sizes 8, 16, 32 and 64 and the bigger a word size is, the faster a computer can run. For example; The word 'Hello' is stored as the binary combination of 0100100001100101011011000110110001101111.
Information technology uses digital data forms by using only two numbers; 0 and 1. these digits easily represent the circuits or systems in a computer or digital technological device as being simply on or off. The digit ‘0’ usually electronically represents ‘off’ and ‘1’ represents the ‘on’ state. Each and every on or off digit is called a “bit” which derives from binary digit. It is the smallest unit of data in a computer and when stored in groups of eight, it is called a “byte”. Digital data can be processed in words which are the number of bits processed in a computer at time. When a computer or device takes a bit to another place by moving it, it takes a word at a time. As technology advances, computers are getting faster. Computers can move bits in words sizes 8, 16, 32 and 64 and the bigger a word size is, the faster a computer can run. For example; The word 'Hello' is stored as the binary combination of 0100100001100101011011000110110001101111.
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How Analogue Data is converted to Digital...When you scan a picture into a scanner, the scanner is doing an analogue to digital conversion. It is taking the analogue information provided by the picture (the light) and converting it to a digital form of an image. Also, when recording yourself onto a computer, an analogue to digital conversion is taking place. The analogue to digital conversion happens by converting your voice which naturally an analogue form of data, into a digital information. An analogue device can use only analogue values and a digital device can use digital values. To be converted into digital, an ADC is used which is short for analogue to digital converter. Whenever we need an analogue signal to come back, a DAC is used which is short for digital to analogue converter.
If we try to attach an analogue device (like a microphone) to a computer (digital device) we will need to convert the analogue data to digital before the data can be used by the digital device. The microphone is used to pass the analogue sound waves through the ADC which will convert the sound to a digital value ready for the computer to use instead of its original form as analogue. The ADC then passes the converted digital data into the computer where the sound can be stored and edited. If we would like to listen to music from our computer or iPod (digital device) on a loudspeaker or headphones (analogue device) we would have to have a DAC attached to convert the digital values from the digital device to analogue values for the analogue device to read and use. The DAC then passes the converted analogue data onto the analogue loudspeaker which we would then hear loud and clear music as sound waves. When an audio disk is being played, the CD player is reading the digital information on the disk and converting it back to analogue data so that the music can be heard. Same with talking on the phone. There are basic reasons as to why digital signals are used instead of analogue. Noise is the first reason. Since analogue signals can assume any values, noise is interpreted as part of the original signalled sound. Digital systems on the other hand understand the binary digits, 0 and 1 only. Anything different from the digital information is discarded. Therefore, unwanted noise won’t be heard when a CD is being played. |