【正文】 大家認(rèn)為 UTC 將作為最終時(shí)間 ， 時(shí)間間隔 ， 頻率標(biāo)準(zhǔn) ， 時(shí)間同步使 UTC 在全世界范圍顯示相同的時(shí) ， 分 ， 秒 .振蕩器同步使 UTC 產(chǎn)生應(yīng)用于時(shí)間間隔和頻率參考標(biāo)準(zhǔn)的信號 . 時(shí)間和頻率測量 時(shí)間和頻率測量可以 應(yīng)用于度量學(xué)的其他領(lǐng)域 .頻率標(biāo)準(zhǔn)或時(shí)鐘測量叫做終端。皮 秒作為一個(gè)小量增加到 UTC 每年一次從 1972 年開始的 。 協(xié)調(diào)全世界時(shí)間 (UTC) 世界的主要度量學(xué)實(shí)驗(yàn)室測量時(shí)間和頻率標(biāo)準(zhǔn) ， 并發(fā)送的 BIPM， 法國 BIPM中北大學(xué) 2021 屆畢業(yè)設(shè)計(jì)說明書 第 12 頁 共 16 頁 收集至少 40個(gè)實(shí)驗(yàn)室的 200多個(gè)原子時(shí)間和頻率標(biāo)準(zhǔn)包括來自國際標(biāo)準(zhǔn)和技術(shù)協(xié)會 (NIST).通過這些平均結(jié)果由 BIPM 產(chǎn)生兩個(gè)時(shí)間標(biāo)準(zhǔn) ， 國際原子時(shí)間 (TAI)和協(xié)調(diào)全世界時(shí)間 (UTC)， 這些時(shí)間標(biāo)準(zhǔn)盡可能地與 SI 標(biāo)準(zhǔn) 接近 。 頻率是一個(gè)事件的重復(fù)次數(shù) ， 如果 T 一個(gè)重復(fù)事件的周期 ， 那么頻率 f 是它的倒數(shù) ， 1/頻率的倒數(shù)是周期 ， T=1/ .很容易看出頻率和時(shí)間間隔關(guān)系很密切 .頻率的標(biāo)準(zhǔn)單位是赫茲 ， 定義為每秒發(fā)生的事件次數(shù)或循環(huán)次數(shù) ， 電信號的頻率通常用不同的赫茲測量 ， 包括千赫茲 ， 兆赫茲 ， 千兆赫茲 .1KHz 相當(dāng)于 每秒發(fā)生一千次事件 ， 1MHz 相當(dāng)于每秒發(fā)生一百萬次事件 .1GHz 相當(dāng)于每秒發(fā)生十億次事件 .產(chǎn)生頻率的裝置叫做振蕩器 ， 設(shè)置不同振蕩器具有相同的頻率叫做同步 。： 學(xué)號： 0705014141 學(xué) 院： 信息與通信工程 專 業(yè)： 電子信息科學(xué)與技術(shù) 指導(dǎo)教師： 李建民 2021年 6月 中北大學(xué) 2021 屆畢業(yè)設(shè)計(jì)說明書 第 1 頁 共 16 頁 外文文獻(xiàn)原文 Fundamentals of Time and Frequency Introduction Time and frequency standards supply three basic types of information： timeofday， time interval， and frequency. Timeofday information is provided in hours， minutes， and seconds， but often also includes the date (month， day， and year). A device that displays or records timeofday information is called a clock. If a clock is used to label when an event happened， this label is sometimes called a time tag or time stamp. Date and timeofday can also be used to ensure that events are synchronized， or happen at the same time. Time interval is the duration or elapsed time between two events. The standard unit of time interval is the second(s). However， many engineering applications require the measurement of shorter time intervals， such as milliseconds (1 ms = 10 3 s) ， microseconds (1 μs = 10 6 s) ， nanoseconds (1 ns = 10 9 s) ， and picoseconds (1 ps = 10 12 s). Time is one of the seven base physical quantities， and the second is one of seven base units defined in the International System of Units (SI). The definitions of many other physical quantities rely upon the definition of the second. The second was once defined based on the earth?s rotational rate or as a fraction of the tropical year. That changed in 1967 when the era of atomic time keeping formally began. The current definition of the SI second is the duration of 9， 192， 631， 770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the cesium133 atom. Frequency is the rate of a repetitive event. If T is the period of a repetitive event， then the frequency f is its reciprocal， 1/T. Conversely， the period is the reciprocal of the frequency， T = 1/f. Since the period is a time interval expressed in seconds (s) ， it is easy to see the close relationship between time interval and frequency. The 中北大學(xué) 2021 屆畢業(yè)設(shè)計(jì)說明書 第 2 頁 共 16 頁 standard unit for frequency is the hertz (Hz) ， defined as events or cycles per second. The frequency of electrical signals is often measured in multiples of hertz， including kilohertz (kHz)， megahertz (MHz)， or gigahertz (GHz)， where 1 kHz equals one thousand (103) events per second， 1 MHz equals one million (106) events per second， and 1 GHz equals one billion (109) events per second. A device that produces frequency is called an oscillator. The process of setting multiple oscillators to the same frequency is called synchronization. Of course， the three types of time and frequency information are closely related. As mentioned， the standard unit of time interval is the second. By counting seconds， we can determine the date and the timeofday. And by counting events or cycles per second， we can measure frequency. Time interval and frequency can now be measured with less uncertainty and more resolution than any other physical quantity. Today， the best time and frequency standards can realize the SI second with uncertainties of ≈ 1 realizations of the other base SI units have much larger uncertainties. Coordinated Universal Time (UTC) The world?s major metrology laboratories routinely measure their time and frequency standards and send the measurement data to the Bureau International des Poids et Measures (BIPM) in Sevres， France. The BIPM averages data collected from more than 200 atomic time and frequency standards