Synchronization
(′siŋ·krə·nə′zā·shən)
(engineering) The maintenance of one operation in step with another, as in keeping the electron beam of a television picture tube in step with the electron beam of the television camera tube at the transmitter. Also known as sync.
The process of maintaining one operation in step with another. The commonest example is the electric clock, whose motor rotates at some integral multiple or submultiple of the speed of the alternator in the power station. In television, synchronization is essential in order that the electron beams of receiver picture tubes are at exactly the same spot on the screen at each instant as is the beam in the television camera tube at the transmitter.
Also called sync. Precise matching of two waves or functions.
(DOD) 1. The arrangement of military actions in time, space, and purpose to produce maximum relative combat power at a decisive place and time. 2. In the intelligence context, application of intelligence sources and methods in concert with the operation plan.
Synchronization is the coordination of events to operate a system in unison. The familiar conductor of an orchestra serves to keep the orchestra in time.
Systems operating with all their parts in synchrony are said to be synchronous or in sync.
Firefighters marching in a parade
Some systems may be only approximately synchronized, or plesiochronous. For some applications relative offsets between events need to be determined, for others only the order of the event is important.
Today, synchronization can occur on a global basis due to GPS-enabled timekeeping systems.
Transport
Apart from its use for navigation (see John Harrison), synchronization was not important in transportation until the nineteenth century, when the coming of the railways made travel fast enough for the differences in local time between adjacent towns to be noticeable (see [1]).
In some territories, sharing of single railroad tracks was controlled by the timetable. Thus strict timekeeping was a safety requirement. To this day[where?], railroads can communicate and signal along their tracks, independently of other systems for safety.
Communication
The lessons of timekeeping are part of engineering technology. In electrical engineering terms, for digital logic and data transfer, a synchronous object requires a clock signal. Timekeeping technologies such as the GPS satellites and Network time protocol (NTP) provide real-time access to a close approximation to the UTC timescale, and are used for many terrestrial synchronization applications.
Synchronization is an important concept in the following fields:
- Computer science (In computer science, especially parallel computing, synchronization refers to the coordination of simultaneous threads or processes to complete a task; in order to obtain correct runtime order and avoid unexpected race conditions.)
- Cryptography
- Multimedia
- Music (Rhythm)
- Neuroscience
- Photography
- Physics (The idea of simultaneity has many difficulties, both in practice and theory.)
- Synthesizers
- Telecommunication
Synchronization has several subtly distinct sub-concepts:
- Phase synchronization
- Rate synchronization
- Time offset synchronization
- Time order synchronization
Uses
- Film synchronization of image and sound in sound film.
- Synchronization is important in fields such as digital telephony, video and digital audio where streams of sampled data are manipulated.
- In electric power systems, alternator synchronization is required when multiple generators are connected to an electrical grid.
- Arbiters are needed in digital electronic systems such as microprocessors to deal with asynchronous inputs. There are also electronic digital circuits called synchronizers that attempt to perform arbitration in one clock cycle. Synchronizers, unlike arbiters, are prone to failure. (See metastability in electronics).
- Encryption systems usually require some synchronization mechanism to ensure that the receiving cipher is decoding the right bits at the right time.
- Automotive transmissions contain synchronizers which allow the toothed rotating parts (gears and splined shaft) to be brought to the same rotational velocity before engaging the teeth.
- Time codes are often used as a means of synchronization in film, video, and audio applications.
- Flash photography, see Flash synchronization
See also
- Asynchrony
- Atomic clock
- Clock synchronization
- Double-ended synchronization
- Einstein synchronization
- Entrainment
- Flywheel
- Homochronous
- Kuramoto model
- Mutual exclusion
- Neural synchronization
- Phase-locked loops
- Reciprocal socialization
- Synchronism
- Synchronization (alternating current)
- Synchronization in telecommunications
- Synchronization of chaos
- Synchronizer
- Synchronous conferencing
- Time
- Timing Synchronization Function (TSF)
- Time transfer
- Timecode
- Tuning fork
In the field of video and audio engineering:
In the field of aircraft gun engineering:
Order synchronization and related topics:
- Rendezvous problem
- Interlocking
- Race condition
- Concurrency control
- Room synchronization
- Transient blocking synchronization
- Comparison of synchronous and asynchronous signalling
Compare with:
- Synchronicity, an alternative organizing principle to causality conceived by Carl Jung.
Notes
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