Dropout (electronics)
Encyclopedia
Dropout within the realm of electronics
and electrical engineering
, has a number of uses.
It is the dropping away of a flake of magnetic material from magnetic tape
, leading to loss of signal, or a failure to properly read a binary
character
from data storage
. In magnetic disk, tape, card, or drum systems, a dropout is a recorded signal with an amplitude
less than a predetermined percentage of a reference
signal. On an optical disc
, it is an area of reduced or obscured reflectivity
due to fingerprint
s, scratch
es, or other damage. It may also be a potential difference
between the input and output terminals of a linear regulator
, below which the regulator can not meet its specifications.
A dropout is also a momentary loss of signal in a communications system
, usually caused by noise
, propagation
anomalies, or system malfunction
s. For analog signal
s, a dropout is frequently gradual and partial, depending on the cause. For digital signal
s, dropouts are more pronounced, usually being sudden and complete, due to the cliff effect
. In mobile telephony
, a dropout of more than a few second
s will result in a dropped call.
Electronics
Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
and electrical engineering
Electrical engineering
Electrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics and electromagnetism. The field first became an identifiable occupation in the late nineteenth century after commercialization of the electric telegraph and electrical...
, has a number of uses.
It is the dropping away of a flake of magnetic material from magnetic tape
Magnetic tape
Magnetic tape is a medium for magnetic recording, made of a thin magnetizable coating on a long, narrow strip of plastic. It was developed in Germany, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders...
, leading to loss of signal, or a failure to properly read a binary
Binary numeral system
The binary numeral system, or base-2 number system, represents numeric values using two symbols, 0 and 1. More specifically, the usual base-2 system is a positional notation with a radix of 2...
character
Character (computing)
In computer and machine-based telecommunications terminology, a character is a unit of information that roughly corresponds to a grapheme, grapheme-like unit, or symbol, such as in an alphabet or syllabary in the written form of a natural language....
from data storage
Data storage device
thumb|200px|right|A reel-to-reel tape recorder .The magnetic tape is a data storage medium. The recorder is data storage equipment using a portable medium to store the data....
. In magnetic disk, tape, card, or drum systems, a dropout is a recorded signal with an amplitude
Amplitude
Amplitude is the magnitude of change in the oscillating variable with each oscillation within an oscillating system. For example, sound waves in air are oscillations in atmospheric pressure and their amplitudes are proportional to the change in pressure during one oscillation...
less than a predetermined percentage of a reference
Reference
Reference is derived from Middle English referren, from Middle French rèférer, from Latin referre, "to carry back", formed from the prefix re- and ferre, "to bear"...
signal. On an optical disc
Optical disc
In computing and optical disc recording technologies, an optical disc is a flat, usually circular disc which encodes binary data in the form of pits and lands on a special material on one of its flat surfaces...
, it is an area of reduced or obscured reflectivity
Reflectivity
In optics and photometry, reflectivity is the fraction of incident radiation reflected by a surface. In general it must be treated as a directional property that is a function of the reflected direction, the incident direction, and the incident wavelength...
due to fingerprint
Fingerprint
A fingerprint in its narrow sense is an impression left by the friction ridges of a human finger. In a wider use of the term, fingerprints are the traces of an impression from the friction ridges of any part of a human hand. A print from the foot can also leave an impression of friction ridges...
s, scratch
Scratch
Scratch may refer to:* A mark or indentation on a surface: Abrasion It may also refer to:- Recordings :* Scratch , by Kaela Kimura* Scratch , the soundtrack to the 2001 documentary Scratch...
es, or other damage. It may also be a potential difference
Voltage
Voltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...
between the input and output terminals of a linear regulator
Linear regulator
In electronics, a linear regulator is a voltage regulator based on an active device operating in its "linear region" or passive devices like Zener diodes operated in their breakdown region...
, below which the regulator can not meet its specifications.
A dropout is also a momentary loss of signal in a communications system
Communications system
In telecommunication, a communications system is a collection of individual communications networks, transmission systems, relay stations, tributary stations, and data terminal equipment usually capable of interconnection and interoperation to form an integrated whole...
, usually caused by noise
Noise
In common use, the word noise means any unwanted sound. In both analog and digital electronics, noise is random unwanted perturbation to a wanted signal; it is called noise as a generalisation of the acoustic noise heard when listening to a weak radio transmission with significant electrical noise...
, propagation
Radio propagation
Radio propagation is the behavior of radio waves when they are transmitted, or propagated from one point on the Earth to another, or into various parts of the atmosphere...
anomalies, or system malfunction
Malfunction
A malfunction is when something functions wrongly or does not function at all.Some types of malfunctions are:*Malfunction , malfunction of a parachute*Sexual malfunction, also called "sexual dysfunction"**See also dyspareunia...
s. For analog signal
Analog signal
An analog or analogue signal is any continuous signal for which the time varying feature of the signal is a representation of some other time varying quantity, i.e., analogous to another time varying signal. It differs from a digital signal in terms of small fluctuations in the signal which are...
s, a dropout is frequently gradual and partial, depending on the cause. For digital signal
Digital signal
A digital signal is a physical signal that is a representation of a sequence of discrete values , for example of an arbitrary bit stream, or of a digitized analog signal...
s, dropouts are more pronounced, usually being sudden and complete, due to the cliff effect
Cliff effect
In telecommunications, the cliff effect or brickwall effect describes the sudden loss of digital signal reception. Unlike analog signals, which gradually fade when signal strength decreases or electromagnetic interference or multipath increases, a digital signal provides data which is either...
. In mobile telephony
Mobile telephony
Mobile telephony is the provision of telephone services to phones which may move around freely rather than stay fixed in one location. Mobile phones connect to a terrestrial cellular network of base stations , whereas satellite phones connect to orbiting satellites...
, a dropout of more than a few second
Second
The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....
s will result in a dropped call.