Digital vs. Analog

Digital vs. Analog

Modern electronic devices - computers, video game consoles, cell phones, iPods, etc. - all store data in digital format.

Digital data gets its name from the fact that almost any type of data in an electronic device - characters, images, video and sound - can be broken down into smaller parts and given numeric (or "digital") values.
For example,

 

●	All individual characters and symbols (keys on the keyboard, plus many others) are assigned a value between 0 and 255.  For example,
	○	The upper-case letter "J" has a value of 74
	○	The lower-case letter "m" has a value of 109
●	Images are broken down into individual dots (pixels), and each pixel is given a 3-part color code (one value for red, blue and green).  For example
	○	204 - 255 - 204 represents a light shade of blacl
	○	An image that is one inch square contains 5,184 pixels (72 x 72).  Each pixel has its' own color, and therefore, needs 3 values to represent it.  Therefore, a one inch square image is represented using 5,184 x 3 = 15,552 values
●	Representing audio and video is more complex ...
	Human beings process audio and video in analog form - a continuous series of waves:                          This is an analog sound wave that is continuous over time (t) and amplitude (A). Torepresent this in digital format, the wave must be divided into many individual parts ("sampling"), and each part assigned a numeric value. When you buy a music CD, the songs are very large, because they have been sampled tens of thousands of times per second, which gives a sound quality that is very close to the original (analog) recording or performance.   When a song is converted to MP3 format, the number of samples is reduced in order to decrease the file size.  Fewer samples results in a smaller file, but poorer sound quality.