同步

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节拍器同步

所谓同步synchronization的本意是指某事物或现象同时进行、同时产生，比如音画同步、动作同步等。

同步也指两个或两个以上随时间变化的量在变化过程中保持一定的相对关系，协调事件以统一地操作一个系统。例如，管弦乐队的指挥使管弦乐队保持同步或及时。如果系统的所有部分都处于同步状态，那么这些系统就是同步的或称之为同步系统synchronous，而非同步系统则称为异步系统asynchronous。

在系统中进行同步，也被称为及时、或者称为同步化的（in sync），指对在一个系统中所发生的事件（event）之间进行协调，在时间上出现一致性与统一化的现象。

在描述不同的系统的同步性时，可以具体表达为不同的同步含义，比如：

形容物理系统的同步：物理系统中两个或几个随时间变化的量，在变化过程中保持一定的相对关系。

多媒体系统的同步：由多媒体数据单元（如音频、视频、文本、图像等）在时域序列上相对位置的约束关系。

社会系统的同步：“城市改革的步子要加快，要从解决国家与企业、企业与职工的关系入手，把适合于当前情况的各项改革措施初步配起套来，协调一致，同步进行。”

信号系统的同步：“今天，世界各地的系统之间可以通过卫星导航信号进行时间同步。”

等等。

Transport

Time-keeping and synchronization of clocks is a critical problem in long-distance ocean navigation. Before radio navigation and satellite-based navigation, navigators required accurate time in conjunction with astronomical observations to determine how far east or west their vessel traveled. The invention of an accurate marine chronometer revolutionized marine navigation. By the end of the 19th century, important ports provided time signals in the form of a signal gun, flag, or dropping time ball so that mariners could check and correct their chronometers for error.

Time-keeping and synchronization of clocks is a critical problem in long-distance ocean navigation. Before radio navigation and satellite-based navigation, navigators required accurate time in conjunction with astronomical observations to determine how far east or west their vessel traveled. The invention of an accurate marine chronometer revolutionized marine navigation. By the end of the 19th century, important ports provided time signals in the form of a signal gun, flag, or dropping time ball so that mariners could check and correct their chronometers for error.

时钟的保时与同步是远程海洋导航中的一个关键问题。在无线电导航和卫星导航之前，导航员需要精确的时间和天文观测来确定他们的船向东或向西航行了多远。精确航海时计的发明彻底改变了海上航行。到了19世纪末，重要的港口以信号枪、旗帜或时间球的形式提供时间信号，以便水手能够检查和纠正他们的计时器的错误。

Synchronization was important in the operation of 19th-century railways, these being the first major means of transport fast enough for differences in local mean time between nearby towns to be noticeable. Each line handled the problem by synchronizing all its stations to headquarters as a standard railway time. In some territories, companies shared a single railroad track and needed to avoid collisions. The need for strict timekeeping led the companies to settle on one standard, and civil authorities eventually abandoned local mean time in favor of railway time.

Synchronization was important in the operation of 19th-century railways, these being the first major means of transport fast enough for differences in local mean time between nearby towns to be noticeable. Each line handled the problem by synchronizing all its stations to headquarters as a standard railway time. In some territories, companies shared a single railroad track and needed to avoid collisions. The need for strict timekeeping led the companies to settle on one standard, and civil authorities eventually abandoned local mean time in favor of railway time.

在19世纪的铁路运营中，同步化是非常重要的，这是第一种主要的运输方式，速度足够快，因此附近城镇之间的当地平均时间差异非常明显。每条线路通过将所有车站与总部同步作为标准的铁路时间来处理这个问题。在一些地区，公司共用一条铁路轨道，需要避免碰撞。由于严格计时的需要，这些公司采用了一个标准，民政部门最终放弃了当地的平均时间，转而采用铁路计时。< ! -- 用户: kvng/rth-- >

Communication

In electrical engineering terms, for digital logic and data transfer, a synchronous circuit requires a clock signal. However, the use of the word "clock" in this sense is different from the typical sense of a clock as a device that keeps track of time-of-day; the clock signal simply signals the start and/or end of some time period, often very minute (measured in microseconds or nanoseconds), that has an arbitrary relationship to sidereal, solar, or lunar time, or to any other system of measurement of the passage of minutes, hours, and days.

In electrical engineering terms, for digital logic and data transfer, a synchronous circuit requires a clock signal. However, the use of the word "clock" in this sense is different from the typical sense of a clock as a device that keeps track of time-of-day; the clock signal simply signals the start and/or end of some time period, often very minute (measured in microseconds or nanoseconds), that has an arbitrary relationship to sidereal, solar, or lunar time, or to any other system of measurement of the passage of minutes, hours, and days.

在电气工程术语中，对于数字逻辑和数据传输，同步电路需要一个时钟信号。然而，“时钟”这个词在这个意义上的使用不同于时钟作为一种记录一天时间的装置的典型意义; 时钟信号仅仅标志着某个时间周期的开始和/或结束，通常是非常分钟(以微秒或纳秒计量) ，这个时间周期与恒星、太阳或月球时间，或与任何其他分钟、小时和天的流逝的测量系统有任意的关系。

In a different sense, electronic systems are sometimes synchronized to make events at points far apart appear simultaneous or near-simultaneous from a certain perspective. (Albert Einstein proved in 1905 in his first relativity paper that there actually are no such things as absolutely simultaneous events.) 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 of this kind.

In a different sense, electronic systems are sometimes synchronized to make events at points far apart appear simultaneous or near-simultaneous from a certain perspective. (Albert Einstein proved in 1905 in his first relativity paper that there actually are no such things as absolutely simultaneous events.) 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 of this kind.

从另一个意义上说，电子系统有时是同步的，以使远距离的事件从某种角度看似乎是同时发生的或近乎同时发生的。(阿尔伯特 · 爱因斯坦在1905年他的第一篇相对论论文中证明，事实上并不存在绝对同时发生的事情。)全球定位系统卫星和网络时间协议(NTP)等计时技术提供了接近协调世界时时间尺度的实时接入，并用于许多此类地面同步应用。

Synchronization is an important concept in the following fields:

Synchronization is an important concept in the following fields:

同步是以下领域的一个重要概念:

• Computer science (In computer science, especially parallel computing, synchronization refers to the coordination of simultaneous threads or processes to complete a task with correct runtime order and no unexpected race conditions.)

• Cryptography

• Lip sync

• Multimedia

• Rhythm

• Neuroscience

• Photography

• Physics (The idea of simultaneity has many difficulties, both in practice and theory.)

• Synthesizers

• Telecommunication

• • Frame synchronization

• • Synchronization (video)

Dynamical systems

See also: Synchronization of chaos

文件:Wesphysdemo - Synchronized Metronomes.webm

A mechanical demonstration of synchronization of oscillators: metronomes, initially out of phase, synchronize through small motions of the base on which they are placed

A mechanical demonstration of synchronization of oscillators: metronomes, initially out of phase, synchronize through small motions of the base on which they are placed

对振荡器同步的机械演示: 节拍器，最初不同相位，通过放置它们的基座的微小运动同步

Synchronization of multiple interacting dynamical systems can occur when the systems are autonomous oscillators. For instance, integrate-and-fire oscillators with either two-way (symmetric) or one-way coupling can synchronize when the strength of the coupling (in frequency units) is greater than the differences among the free-running natural oscillator frequencies. Poincare phase oscillators are model systems that can interact and partially synchronize within random or regular networks. In the case of global synchronization of phase oscillators, an abrupt transition from unsynchronized to full synchronization takes place when the coupling strength exceeds a critical threshold. This is known as the Kuramoto model phase transition. Synchronization is an emergent property that occurs in a broad range of dynamical systems, including neural signaling, the beating of the heart and the synchronization of fire-fly light waves.

Synchronization of multiple interacting dynamical systems can occur when the systems are autonomous oscillators. For instance, integrate-and-fire oscillators with either two-way (symmetric) or one-way coupling can synchronize when the strength of the coupling (in frequency units) is greater than the differences among the free-running natural oscillator frequencies. Poincare phase oscillators are model systems that can interact and partially synchronize within random or regular networks. In the case of global synchronization of phase oscillators, an abrupt transition from unsynchronized to full synchronization takes place when the coupling strength exceeds a critical threshold. This is known as the Kuramoto model phase transition. Synchronization is an emergent property that occurs in a broad range of dynamical systems, including neural signaling, the beating of the heart and the synchronization of fire-fly light waves.

当系统是自治振子时，多个相互作用的动力系统可以发生同步。例如，当耦合强度(频率单位)大于自由运行的固有振荡器频率之间的差异时，具有双向(对称)或单向耦合的集成激发振荡器可以同步。庞加莱相位振荡器是一种模型系统，它可以在随机或规则的网络中相互作用和部分同步。当耦合强度超过一个临界阈值时，相位振荡器的全局同步会发生从不同步到完全同步的突变。这就是仓本模型的相变。同步是一个突现的性质，发生在广泛的动态系统，包括神经信号，心脏的跳动和同步的消防蝇光波。

Human movement

Synchronization of movement is defined as similar movements between two or more people who are temporally aligned. This is different to mimicry, as these movements occur after a short delay. Muscular bonding is the idea that moving in time evokes particular emotions. This sparked some of the first research into movement synchronization and its effects on human emotion.

Synchronization of movement is defined as similar movements between two or more people who are temporally aligned. This is different to mimicry, as these movements occur after a short delay. Muscular bonding is the idea that moving in time evokes particular emotions. This sparked some of the first research into movement synchronization and its effects on human emotion.

运动同步定义为两个或两个以上时间排列的人之间相似的运动。这与模仿不同，因为这些动作是在短暂的延迟之后发生的。肌肉粘合是指时间的移动能够唤起特定的情感。这引发了一些关于运动同步及其对人类情感影响的第一次研究。

In groups, synchronization of movement has been shown to increase conformity, cooperation and trust.模板:Failed verification Military step has long been used for these purposes but more research on group synchronization is needed to determine its effects on the group as a whole and on individuals within a group. In dyads, groups of two people, synchronization has been demonstrated to increase affiliation, self-esteem, compassion and altruistic behaviour and increase rapport. During arguments, synchrony between the arguing pair has been noted to decrease, however it is not clear whether this is due to the change in emotion or other factors. There is evidence to show that movement synchronization requires other people to cause its beneficial effects, as the effect on affiliation does not occur when one of the dyad is synchronizing their movements to something outside the dyad. This is known as interpersonal synchrony.

In groups, synchronization of movement has been shown to increase conformity, cooperation and trust. Military step has long been used for these purposes but more research on group synchronization is needed to determine its effects on the group as a whole and on individuals within a group. In dyads, groups of two people, synchronization has been demonstrated to increase affiliation, self-esteem, compassion and altruistic behaviour and increase rapport. During arguments, synchrony between the arguing pair has been noted to decrease, however it is not clear whether this is due to the change in emotion or other factors. There is evidence to show that movement synchronization requires other people to cause its beneficial effects, as the effect on affiliation does not occur when one of the dyad is synchronizing their movements to something outside the dyad. More research is required to separate the effect of intentionality from the beneficial effect of synchrony.

在群体中，运动的同步性被证明可以增加顺从性、合作性和信任度。军事步骤一直被用于这些目的，但需要更多的研究组同步，以确定其对群体作为一个整体和群体中的个人的影响。在两人一组的情况下，同步性被证明可以增加亲密关系、自尊、同情心和利他行为，并且增加融洽的关系。在争吵过程中，争吵双方的同步性降低了，但是不清楚这是由于情绪的变化还是其他因素。有证据表明，运动同步需要其他人产生其有益的效果，因为当其中一个二分体同步他们的运动到二分体之外的某个东西时，对联系的影响不会发生。需要进行更多的研究，以区分意向性的效果和同步性的有利效果。

There has been dispute regarding the true effect of synchrony in these studies. Research in this area detailing the positive effects of synchrony, have attributed this to synchrony alone; however, many of the experiments incorporate a shared intention to achieve synchrony. Indeed, the Reinforcement of Cooperation Model suggests that perception of synchrony leads to reinforcement that cooperation is occurring, which leads to the pro-social effects of synchrony. More research is required to separate the effect of intentionality from the beneficial effect of synchrony.

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. More sophisticated film, video, and audio applications use time code to synchronize audio and video.

• Synchronization of video frames from multiple cameras for 3D reconstruction

• 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 that bring the toothed rotating parts (gears and splined shaft) to the same rotational velocity before engaging the teeth.

• Flash synchronization synchronizes the flash with the shutter.

Some systems may be only approximately synchronized, or plesiochronous. Some applications require that relative offsets between events be determined. For others, only the order of the event is important.

有些系统可能只是近似同步的，或者是同步的。有些应用程序要求确定事件之间的相对偏移量。对于其他人来说，只有事件的顺序才是重要的。

Some systems may be only approximately synchronized, or plesiochronous. Some applications require that relative offsets between events be determined. For others, only the order of the event is important.

See also

• Synchronicity, an alternative organizing principle to causality conceived by Carl Jung.

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External links

• 模板:Commonscatinline

• J. Domański "Mathematical synchronization of image and sound in an animated film"

Category:Systems

类别: 系统

This page was moved from wikipedia:en:Synchronization. Its edit history can be viewed at 同步/edithistory