mso-hansi-font-family:"Times New Roman"">一、概述

mso-hansi-font-family:"Times New Roman"">　　在這里我們主要介紹互聯(lián)網(wǎng)時(shí)間同步技術(shù)及產(chǎn)品，也就是通過(guò)支持NTP mso-hansi-font-family:"Times New Roman"">協(xié)議的GPS "Times New Roman"">時(shí)鐘服務(wù)器（上海銳呈K mso-hansi-font-family:"Times New Roman"">系列）實(shí)現(xiàn)網(wǎng)絡(luò)時(shí)間同步。

? "Times New Roman"">二、時(shí)間同步網(wǎng)絡(luò)技術(shù)

??? "Times New Roman"">目前有多種時(shí)間同步技術(shù)，每一種技術(shù)都各有特點(diǎn)，不同技術(shù)的時(shí)間同步精度也存在較大的差異。長(zhǎng)短波授時(shí)時(shí)間同步技術(shù)，GPS mso-hansi-font-family:"Times New Roman"">時(shí)間同步技術(shù)

mso-hansi-font-family:"Times New Roman"">　　三、選用上海銳呈的GPS "Times New Roman"">時(shí)鐘服務(wù)器解決時(shí)間同步問(wèn)題。

mso-hansi-font-family:"Times New Roman"">　　銳呈GPS "Times New Roman"">時(shí)鐘服務(wù)器產(chǎn)品采用19 mso-hansi-font-family:"Times New Roman"">英寸1U "Times New Roman"">機(jī)架式設(shè)計(jì)，內(nèi)置GPS "Times New Roman"">北斗接收機(jī)，以GPS "Times New Roman"">北斗衛(wèi)星時(shí)間為標(biāo)準(zhǔn)時(shí)間源，支持NTP "Times New Roman"">協(xié)議（V2.0/V3.0/V4.0 "Times New Roman"">）和SNTP協(xié)議，可以為局域網(wǎng)內(nèi)成百上千的計(jì)算機(jī)、路由器等提供時(shí)間校準(zhǔn)來(lái)達(dá)到整個(gè)網(wǎng)絡(luò)時(shí)間同步。

mso-hansi-font-family:"Times New Roman"">四、GPS "Times New Roman"">時(shí)鐘服務(wù)器的特點(diǎn)

1．時(shí)間精度高，同步速度快，收星穩(wěn)定。

2．守時(shí)精度高。裝置內(nèi)部守時(shí)單元采用了時(shí)間頻率測(cè)控技術(shù)與智能馴服算法，晶體選用高精度恒溫晶體振蕩器，使裝置守時(shí)準(zhǔn)確度優(yōu)于7*10-9(0.42μS/ mso-hansi-font-family:"Times New Roman"">分鐘) "Times New Roman"">，即在外部時(shí)間基準(zhǔn)異常的情況下，每天時(shí)鐘走時(shí)誤差不超過(guò)0.6mS "Times New Roman"">。

3．模塊化結(jié)構(gòu)，NTP mso-hansi-font-family:"Times New Roman"">端口數(shù)量可靈活配置，配置14 "Times New Roman"">路NTP/SNTP "Times New Roman"">網(wǎng)絡(luò)對(duì)時(shí)信號(hào)。

4．雙CPU mso-hansi-font-family:"Times New Roman"">同時(shí)工作，32 "Times New Roman"">位CPU雙核處理器，性能提高。

5．支持單GPS mso-hansi-font-family:"Times New Roman"">、單北斗、雙GPS "Times New Roman"">、雙北斗、 GPS/ "Times New Roman"">北斗雙系統(tǒng)衛(wèi)星接收機(jī)配置。

6．可同時(shí)為幾十萬(wàn)臺(tái)客戶端、服務(wù)器、工作站提供時(shí)間服務(wù)。

7．支持WINDOWS9X/NT/2000/XP/2003/2008/2012、LINUX mso-hansi-font-family:"Times New Roman"">、UNIX "Times New Roman"">、SUN SOLARIS "Times New Roman"">等操作系統(tǒng)及支持NTP "Times New Roman"">協(xié)議的路由器、交換機(jī)、智能控制器等網(wǎng)絡(luò)設(shè)備。

8．專(zhuān)用嵌入式系統(tǒng)，無(wú)硬盤(pán)和風(fēng)扇設(shè)計(jì)，防震設(shè)計(jì)，系統(tǒng)穩(wěn)定可靠。

9.裝置有電源中斷告警、GPS/ mso-hansi-font-family:"Times New Roman"">北斗失步告警、外部“B "Times New Roman"">碼輸入”（后備時(shí)間基準(zhǔn)）消失告警多路報(bào)警（繼電器空接點(diǎn)）信號(hào)輸出。

10．裝置前面板有“電源指示”燈、“秒脈沖指示” "Times New Roman"">燈、“GPS/ "Times New Roman"">北斗信號(hào)輸入” 燈、“B mso-hansi-font-family:"Times New Roman"">碼信號(hào)輸入” 燈、“GPS/ mso-hansi-font-family:"Times New Roman"">北斗信號(hào)輸入異?！?/span> "Times New Roman"">燈、“B碼信號(hào)輸入異?！?/span> "Times New Roman"">燈多種工作狀態(tài)指示，便于運(yùn)行值班人員的日常巡視。

11．裝置不僅實(shí)現(xiàn)了板卡全兼容，還提供了豐富的信號(hào)接口資源和開(kāi)放式特殊接口設(shè)計(jì)平臺(tái)，具備兼容能力。裝置可提供多路脈沖信號(hào)、IRIB-B mso-hansi-font-family:"Times New Roman"">信號(hào)、DCF77 "Times New Roman"">信號(hào)（有源、無(wú)源）、時(shí)間報(bào)文、PTP "Times New Roman"">、NTP/SNTP "Times New Roman"">網(wǎng)絡(luò)時(shí)間信號(hào)。

mso-hansi-font-family:"Times New Roman"">五、GPS "Times New Roman"">時(shí)鐘服務(wù)器的詳細(xì)參數(shù)：

1．時(shí)間源：GPS mso-hansi-font-family:"Times New Roman"">、北斗、CDMA "Times New Roman"">、IRIG-B "Times New Roman"">、恒溫晶振OCXO "Times New Roman"">、原子鐘可選；

2．電源：220V/110V交、直流自適應(yīng), mso-hansi-font-family:"Times New Roman"">雙電源冗余；

3．GPS mso-hansi-font-family:"Times New Roman"">接收頻率：1575.42MHz, "Times New Roman"">接收靈敏度：捕獲〈-160dBW "Times New Roman"">，跟蹤〈-163dBW "Times New Roman"">。捕獲時(shí)間：裝置冷啟動(dòng)時(shí)，〈5min "Times New Roman"">；裝置熱啟動(dòng)時(shí)，〈1min "Times New Roman"">。

4．北斗接收器：接收頻率（BD2 B1 ）：1561.098±4MHz mso-hansi-font-family:"Times New Roman"">。接收機(jī)靈敏度：-157.6dBW "Times New Roman"">；

TTFF：冷啟動(dòng):32s, mso-hansi-font-family:"Times New Roman"">熱啟動(dòng):1s, "Times New Roman"">失鎖重捕獲:<1s "Times New Roman"">。

5．平均無(wú)故障間隔時(shí)間(MTBF) mso-hansi-font-family:"Times New Roman"">≥80000 "Times New Roman"">小時(shí)；平均維修時(shí)間（MTTR "Times New Roman"">）：一般不大于30 "Times New Roman"">分。正常使用條件下無(wú)須維護(hù)。

6．B mso-hansi-font-family:"Times New Roman"">碼：0.1 "Times New Roman"">μS，串口：10 mso-hansi-font-family:"Times New Roman"">μS "Times New Roman"">，NTP/SNTP "Times New Roman"">：0.2-10ms "Times New Roman"">；

7．網(wǎng)口支持協(xié)議：NTP/SNTP ，ARP mso-hansi-font-family:"Times New Roman"">，UDP/ Time "Times New Roman"">，Telnet "Times New Roman"">，ICMP，SNMP mso-hansi-font-family:"Times New Roman"">，MD5

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