digital

1. Information science: (1) Finite, discontinuous phenomenon (such as an on, or off, light bulb) as opposed to infinitely varying and continuous analog phenomenon (such as brightness of the sunlight during day). (2) Representation of data or information in figures (such as in a table) in contrast to as a chart, graph, drawing, or other pictorial form. Digital devices show only the divisions or subdivisions but not the quantities between them. For example, a digital watch may show hours, minutes, and seconds each as a whole number only. In summary, digital information is (a) discrete, (b) counted, and (c) accurate (as opposed to precise).

2. Communications: One of only two methods (the other is analog) of converting data into electrical signals. Digital technology transmits data in a code represented by two states on or off (presence or absence of) electrical voltage, represented in literature by symbols '1' and '0' which together are called binary digits. For example, a digital mobile phone converts sound into a binary code and sends it as on-off electrical impulses which are reconverted into sound at the receiving end. Since digital signal transmission does not resemble electrical signals generated in nature, it is less prone to errors due to 'line noise' and electrical disturbances caused by the natural phenomenon such as weather and sun spots. Every reproduction of digital data is an exact facsimile of the original because it's the code, and not the waveform, that is copied. However, for the same amount of data, digital transmission requires comparatively larger bandwidth than analog transmission because the transmission medium has to carry far more information. Though it took off only in 1960s when integrated circuits and microprocessors were invented (which can process data into a code and back into data almost instantly), digital communication was employed first in telegraphy. During the telegraph era (1840s to 1960s) letters, numbers, and punctuation marks comprising a message were converted into electrical impulses by using Morse code. This code comprised of only two characters one represented by a short tap (called 'dot') and the other by a long tap (called 'dash') on the telegraph key.

3. Computing: Representation of a quantity (data) by a two-digit (binary) code. A digital computer represents every kinds of data (text, graphics, numbers, sound, video) by the presence or absence of electrical pulses of equal strength. All modern computers are digital, because digital circuits and computer chips (since they need to handle only two numbers, 1 and 0) are much faster than analog ones in data processing.