Synchronization
Synchronization (from Greek συν ( sýn ), "together" and χρόνος ( Chronos ), "Time ", literally about " making synchronism" ), also equivalent synchronization refers to the temporal succession - tuning operations. Synchronization thus ensures that actions in a certain order or occur simultaneously, that is to occur synchronously.
In various fields of knowledge, the term synchronization is commonly used in the narrower meanings:
Digital playback devices
Synchronizing means in this context, the individual elements on the playback device such as an MP3 player to adapt to a data source (eg music player on the computer). That is, the reproducing apparatus is identical to the data source according to the synchronization.
A frequently encountered synchronizing digital media is the appointment of programs, for example, on a computer in the workplace Manage calendar. In order also to be adjusted to calendar enabled Palm devices or modern mobile phones their calendar with the " steady-state" busy schedule, there are numerous synchronization programs, via the various media (eg, cable, Bluetooth, Wi-Fi ) compare the two calendars together. There are several possibilities for synchronization. In the one-sided all appointments are sent from one device to another; in the two-sided all data will be sent to each of the two devices. This can then lead to duplicate entries, it must then catch the synchronization software.
Always popular are also web services that (that is, indirectly through advertising funded mostly " free " ) for common devices offer global synchronization.
Film
Main article: synchronization (film )
Synchronization refers to the film, the " simultaneous " running of picture and sound. The dubbing of films is commonly referred to as synchronization. In Germany, non- German language films are synchronized since the 1930s. But also in other countries such as the USA, Italy, Spain, China and Japan films are dubbed into the local language, in the Asian countries mostly English synchronizations are made for the international market (see also voice actors, sound engineer ). Also, the singing singers on a playback or dubbing of other instrument voices is denoted by synchronization; see also overdubbing.
TV
When watching TV the playback device must be synchronized to the transmitter, so that the information sent will be displayed in the correct place on the screen. Because of the grid of rows that are written sequentially, one distinguishes horizontal and vertical synchronization. Electrically these signals can be performed either separately next to the ( amplitude modulated ) signal brightness or combined with this in an appropriate manner to the composite video or composite signal that it then also can be easily separated again.
A particular object must satisfy the synchronous signals interlacing methods, namely the alternating switching the display of even and odd rows depending on field. For this, the horizontal pulse must be within the vertical blanking interval one half row is earlier ( most easily by frequency doubling ) so that the first line of the second field starts at the top in the middle of the screen, where the written in the preceding field first line already sunk deeper half a line is. The same is true for analog computer monitors when they at higher resolutions the same procedure ( so-called interlace, no longer used today, as can process all new monitors horizontal frequencies up to 85 kHz and above).
For monitors there is still a further variant of the synchronous signal routing: For some devices, with separate entrances (usually BNC connector) for the 3 ( RGB ) color components or 2 color difference 1 brightness signal ( component video ), the sync signal as in a similar manner up in the green (or brightness (Y) ) signal mixed: Sync on Green. Most of the sync signal can optionally be connected separately, with the horizontal and vertical signal depending on the device either combined (1 port), or is separated into two separate connections. In the usual VGA port today, the sync signals on different pins from the same connector to be transferred.
If the sync signals are not transferred properly ( smoothly ) or not properly evaluated, it produces a characteristic interference. Since the image change runs the slowest (typically 50-100 Hz), errors can track most closely with the naked eye you here: The " running ( vertical) by", but can still be seen halfway. Sometimes the synchronization locks also in the wrong place the vertical, for example, in significant image content with a corresponding voltage swing is displayed so that the image offset, with a thick black bar in the middle. However, if the horizontal synchronization fails, " through the rows (horizontal) by " perform a " belly dance " or are moved irregularly and it is hardly a picture content can be seen; in the most favorable case, the image is inclined to the left or right.
Electronics
In digital technology, synchronization means that two devices (eg, transmitter and receiver) synchronized when both operate at a clock frequency that is equal to within specified tolerances. The signals synchronized devices have a fixed phase relationship to each other. The process for which most of the German technical term synchronism method is used, is referred to as synchronization or with reference to the English technical term synchronization.
Synchronization of a synchronous machine
To turn a synchronous machine connected to the grid, certain synchronization conditions are observed ( also paralleling conditions ). No voltage difference may exist between the terminals of the network and those of the machine. This is achieved when the following conditions are met:
- Same frequency - control eg via speed control or double frequency meter; Intervention on change in speed of the machine
- Same phase sequence - eg control via rotary field measurement; Intervention via exchange of two phases
- Same phase - control eg via Zweistrahloszillograph; Intervention by short-term change in speed of the machine
- Voltage equality - for example, control over two voltmeter; Intervention on changing the excitation current of the machine
Should these conditions not be met, it is depending on the amount of the difference to be more or less great moments because the machine is trying to pull in the synchronous run. These moments act on the machine and machine foundation and can cause damage or even destruction.
In modern plants will no longer be synchronized manually. This task is carried out, for example in power plants of control and must, except in the initiation, none human intervention.
Computer science
In computer science, synchronization refers to:
- Process synchronization, processes that govern the shared access of processes to shared resources. The synchronization process ensures that resources are allocated efficiently and keep data in a consistent state. See also parallelization and sequentialization.
- The causal order of events by means of timestamps. This ordering ensures that the logical sequence of events is preserved. See also Logical clock.
- The matching of data in a distributed system, see Replication. One distinguishes one-way synchronization in which the data of a subsystem to be treated preferably by a bidirectional synchronization, wherein the data of all sub-systems are equal. Program for synchronizing files are eg rsync and Unison. In the area of mobile data technology, it refers to the synchronization of the state of address books and appointments on various mobile devices such as smartphones and tablets with each other and desktop PCs.
Dynamic system
An interaction of two or more dynamic systems can be generated by coupling of its differential equations. If this coupling is strong enough, two chaotic systems can be synchronized.
Vehicle Technology
In the transmission technique is meant by the phrase sync the matching of the rotational speeds of the shift sleeve and gear wheel. A gear change can only take place when the camming to loose wheel of the to switching gear and the shaft on which this idler gear sits at the same speed, because a fit is produced, usually with interlocking claws. Usually this is done by aligning a conical friction between the synchronizer ring, which is coupled via a synchronizing body of the shaft, and a cone on the gear wheel, as long as the shaft and gear wheel rotate at different speeds. The resulting friction torque twisted the synchronizer ring by about half the pitch of the selector teeth so long to have the same shaft and gear wheel speed.
If synchronization is completed (on the speed of the gear wheel by friction or braking or accelerating from the clutch disc loose in the disengaged state idler input shaft), can be switched easily and noiselessly. Will not sync " pop", the mass moments of inertia of too slow or too fast running lots shaft portion in the mouth, which can lead to greatly increased wear on the claws or damage. Synchronizer rings are wearing parts; usually wears the synchronizing ring of the second speed first, because it is used most commonly. Very old vehicles that do not have synchronizer rings ( non-synchromesh gearbox ) or any part of the course no synchronization (some synchronized transmission ), require the careful approach with intermediate gas, is engaged by means of which the transmission neutral short again to the empty revolving part approximately in the speed to adapt to the connection partner whose speed is determined by the speed and the selected gear ratio.
Carburetor synchronization: If motors are ventilated with several carburettors parallel, the carburetor must be synchronized to each other. Are activated by the carburetor via Bowden cables or rods. Unequal match on the trains or in the linkage lead but to the fact that the carbs are not equal wide open at idle or when the throttle is open the same time. This in turn leads to a different filling of the cylinder with the fuel-air mixture. The consequences are different working pressures in the cylinders, lack of maximum power, poor exhaust values and possibly unwanted vibrations of the engine.
For a carburetor synchronization several sub- pressure gauges are used to compare at least two, but ideally as many vacuum gauges such as carburetor systems are in place: for motorcycles up to six, for example, Honda CB 1000 in sports car engines some more (old racing engines from Ferrari, etc.). Are located on the carburetors themselves or to the Ansaugrohrbrücken per cylinder or carburettor system per individual usually sealed with screw connection holes to which the vacuum gauges are connected via screw terminals and hoses. First of all idle suction conditions are harmonized (same pressure conditions by adjusting the individual throttle stops ), then the uniform lifting of all elements is set or controlled throttle when accelerating. When set correctly, all cylinders are evenly supplied with fuel-air mixture, both at idle and under all load conditions.
In extreme cases ( multiple carburetor ) are not only the "small" systems operate synchronously to each other ( the carburetor subsystems for idle and low load ), but also the downstream opening "big pipes " for high loads (eg at Mercedes 230-6 / 8, 250/8, BMW 2500, BMW 2800 and similar vehicles ).
Prerequisite for a good carburetor synchronization a mechanical firing on all cylinders equally good running engine is compression values of the individual cylinders within the tolerance limits, valves properly set ignition timing ok, spark ok, and the carburetor all with the same nozzle elements equipped (in the case. defective, to be restored vehicles, a not unusual errors that unequal bedüste carburetors are installed) After some 100 km the spark plug picture ( color of the insulator ) can shed light on inequalities or a "bad" cylinder ( to light gray: cylinder running too lean or. gets too little gasoline; dark color towards black: Cylinder running " too fat ", with too much fuel ).
Experienced riders of BMW two-cylinder motorcycles do it sometimes, the only observation of mechanical vibrations cleanly to synchronize two carburetors without vacuum gauges: by minimizing the mirror vibrations on the handlebars.
The procedure for vehicle engines differs from the approach used in aircraft engines. In automotive engines the return spring closes the carburetor, in aircraft engines, the return spring opens the carburetor. The pilot is thus also with cracked Bowden performance.
Typical vacuum levels in the intake of gasoline engines, which are used in automobiles, motorcycles and aircraft are bar and -0.4 bar between -0.15. The higher the specific power output of an engine, the lower the negative pressure in the intake system.
The maximum negative pressure differential of the carburettor with each other should not be more than 1/ 100 bar. Thus, very high demands on the accuracy of the pressure gauge. Capsule pressure gauges with zero-point adjustment fulfill this requirement.