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如何运用IEEE 1588达成高精度的时间同步 2020-12-09 10:00:00
  • QIEEE1588可以替代GPS吗？

    A It's possible. 

  • Q对应用环境是否有要求？

    ATemp range is –40 to +85 °C  .tb_button {padding:1px;cursor:pointer;border-right: 1px solid #8b8b8b;border-left: 1px solid #FFF;border-bottom: 1px solid #fff;}.tb_button.hover {borer:2px outset #def; background-color: #f8f8f8 !important;}.ws_toolbar {z-index:100000} .ws_toolbar .ws_tb_btn {cursor:pointer;border:1px solid #555;padding:3px} .tb_highlight{background-color:yellow} .tb_hide {visibility:hidden} .ws_toolbar img {padding:2px;margin:0px}

  • Q时钟源一般从哪儿来？

    AFrom optical communications such as PDH/SDH/SONET/OTN, to Ethernet networking with higher SLA, to today's 5G equipment like RU or DU, you would see 1PPS from Satellite, PTP, SyncE and local reference clock as close sources.

  • Q这种网络时钟同步频率为多少？

    A Normally 1588 solution would need a 1PPS (1Hz) as well as a high frequency (as high as 500MHz) clock as the TOD counter clock (i.e. PTP system clock).

  • Q咱们是提供怎么样的解决方案？

    AA complete 1588 solution involves both software (i.e. PTP control loop) and hardware (i.e. PLL IC with DCO capability). Silabs has both.

  • Q时间同步的格式一般是什么样子的？

    AIEEE 1588 uses the Wall Clock concept, that is it uses the Time of Day (ToD), not only hours, minutes, and seconds, but also the number of nanoseconds within the second. More precisely, PTP carries time that consists of 48 bits worth of seconds, and 32 bits worth of nanoseconds.  In short, these are the TOD counters that we need to synchronize at each node if we are talkign about T-BC node. 

  • Q时钟多久会产生偏移？

    A There are different performance spec available. For example, Stratum 2, there are two primary requirements (see the clock requirements summary table in the GR-1244-CORE SONET standard, “Clocks for the Synchronized Network: Common Generic Criteria” available from Telcordia Technologies):  • 1.6 × 10−8 or 16 part per billion (ppb) free-run accuracy over a period of 20 years with no outside reference • 1 × 10−10 or 0.1 ppb stability over a period of 24 hours in holdover mode .tb_button {padding:1px;cursor:pointer;border-right: 1px solid #8b8b8b;border-left: 1px solid #FFF;border-bottom: 1px solid #fff;}.tb_button.hover {borer:2px outset #def; background-color: #f8f8f8 !important;}.ws_toolbar {z-index:100000} .ws_toolbar .ws_tb_btn {cursor:pointer;border:1px solid #555;padding:3px} .tb_highlight{background-color:yellow} .tb_hide {visibility:hidden} .ws_toolbar img {padding:2px;margin:0px}

  • Q时间同步的精度可以达到什么水平？

    A ns level

  • Q1.时间同步这个高精度能精确到什么等级，秒 毫秒 还是US? 2.IEEE1588完整芯片量产了吗？ 3.IEEE1588协议在工业自动化中起到什么样的作用？ 4.IEEE1588协议能不能实现us级别的同步采集，在电网里面会有这种需求？ 5.IEEE1588协议的工作模式？

    A 1.时间同步这个高精度能精确到什么等级，秒 毫秒 还是US? [DY] ns level 2.IEEE1588完整芯片量产了吗？ [DY] Yes, it's in production. 3.IEEE1588协议在工业自动化中起到什么样的作用？ [DY] For industrial automation that requires machine-to-machine or machine-to-human automated interactions. 4.IEEE1588协议能不能实现us级别的同步采集，在电网里面会有这种需求？[DY] Yes, power grid communication is a target application for 1588. 5.IEEE1588协议的工作模式？[DY] I am not sure what this question is about but IEEE as well as G.8261 and G.8273.2 have defined how 1588 works as well as different requriements for different applications.

  • Q对环境是否有要求？

    AIf your question is related to the operating temperature and how it impacts the accuracy or stability, then yes, you do need to consider it. For 5G equipment like RU or DU, you could have 1PPS, PTP, SyncE and local reference clock as possible clock/synchronization sources and there would be switching mechanism between them as defined by the standards. Wrt switching, there would be holdover feature as well and once it’s in holdover, your selection of XO/TCXO/OCXO as the reference to Silabs PLL IC will impact the stability. Silabs’ solution supports hitless switching as well as holdover.

  • Qsilicon的网络时钟同步方案有哪些优势？

    A我们高度集成、灵活的 IEEE 1588 硬件和 AccuTime™ 软件解决方案可为要求 IEEE 1588-2008 与同步以太网 (SyncE) 相位和频率同步的应用提供支持。我们符合标准的高集成度模块使得开发者非常易于在设计中采用 IEEE 1588，Silicon Labs网络同步器时钟具有频率灵活性和行业领先的低抖动性能，再结合AccuTime™软件，可提供一套完整的 IEEE 1588 解决方案。AccuTime软件采用独特的前沿算法，该算法专为动态适应不断变化的网络状况而设计，旨在减少数据包延迟变化。

  • Q网络时钟同步会有多少延时？

    A Latency has a lot of factors but latency variation is what we are trying to solve and it will impact time/phase synchronization the most..tb_button {padding:1px;cursor:pointer;border-right: 1px solid #8b8b8b;border-left: 1px solid #FFF;border-bottom: 1px solid #fff;}.tb_button.hover {borer:2px outset #def; background-color: #f8f8f8 !important;}.ws_toolbar {z-index:100000} .ws_toolbar .ws_tb_btn {cursor:pointer;border:1px solid #555;padding:3px} .tb_highlight{background-color:yellow} .tb_hide {visibility:hidden} .ws_toolbar img {padding:2px;margin:0px}

  • Q时钟数据通过什么传输给其他设备？

    AThe essence of IEEE PTP 1588 is to use the data plane (i.e. the link that is used to transmit data) to also transmit "time" information and to try to achieve time synchronization. The link could be optical or even copper. In the case of 5G fronthaul, the link would be optical Ethernet running at 10G now, moving to 25G and higher in the future.

  • Q最高对时精度可以到多少啊 可以到ns级的精度吗

    AYes

  • Q网络时钟同步技术目前存在哪些挑战？

    AWith IEEE 1588, time synchronization is achieved via sending/receiving/processing PTP packets. Therefore, the accuracy of timestamping, a process that stamps a "time" on the Tx and Rx PTP packets, is one of the challenges that is the most difficult to solve at this time. Even with hardware timestamping, there are variations/inaccuracies that are difficult to deal with..tb_button {padding:1px;cursor:pointer;border-right: 1px solid #8b8b8b;border-left: 1px solid #FFF;border-bottom: 1px solid #fff;}.tb_button.hover {borer:2px outset #def; background-color: #f8f8f8 !important;}.ws_toolbar {z-index:100000} .ws_toolbar .ws_tb_btn {cursor:pointer;border:1px solid #555;padding:3px} .tb_highlight{background-color:yellow} .tb_hide {visibility:hidden} .ws_toolbar img {padding:2px;margin:0px}

  • Q应用到无人驾驶是否有哪些安全隐患？

    A Please refer to the appropriate standard..tb_button {padding:1px;cursor:pointer;border-right: 1px solid #8b8b8b;border-left: 1px solid #FFF;border-bottom: 1px solid #fff;}.tb_button.hover {borer:2px outset #def; background-color: #f8f8f8 !important;}.ws_toolbar {z-index:100000} .ws_toolbar .ws_tb_btn {cursor:pointer;border:1px solid #555;padding:3px} .tb_highlight{background-color:yellow} .tb_hide {visibility:hidden} .ws_toolbar img {padding:2px;margin:0px}

  • Q延迟特别敏感是何具体概念？

    A Not sure what this question is trying ask..tb_button {padding:1px;cursor:pointer;border-right: 1px solid #8b8b8b;border-left: 1px solid #FFF;border-bottom: 1px solid #fff;}.tb_button.hover {borer:2px outset #def; background-color: #f8f8f8 !important;}.ws_toolbar {z-index:100000} .ws_toolbar .ws_tb_btn {cursor:pointer;border:1px solid #555;padding:3px} .tb_highlight{background-color:yellow} .tb_hide {visibility:hidden} .ws_toolbar img {padding:2px;margin:0px}

  • Q对延迟特别敏感有哪些解决妙招？

    A A combination of software algorithm, hardware PLL IC and carefully design of timestamping.tb_button {padding:1px;cursor:pointer;border-right: 1px solid #8b8b8b;border-left: 1px solid #FFF;border-bottom: 1px solid #fff;}.tb_button.hover {borer:2px outset #def; background-color: #f8f8f8 !important;}.ws_toolbar {z-index:100000} .ws_toolbar .ws_tb_btn {cursor:pointer;border:1px solid #555;padding:3px} .tb_highlight{background-color:yellow} .tb_hide {visibility:hidden} .ws_toolbar img {padding:2px;margin:0px}

  • QIEEER1588中有哪些时间收敛算法？

    A Linux PTP is open sourced and Silabs' AccuTime is a better algorithm to achieve better performance..tb_button {padding:1px;cursor:pointer;border-right: 1px solid #8b8b8b;border-left: 1px solid #FFF;border-bottom: 1px solid #fff;}.tb_button.hover {borer:2px outset #def; background-color: #f8f8f8 !important;}.ws_toolbar {z-index:100000} .ws_toolbar .ws_tb_btn {cursor:pointer;border:1px solid #555;padding:3px} .tb_highlight{background-color:yellow} .tb_hide {visibility:hidden} .ws_toolbar img {padding:2px;margin:0px}

  • Q同步精度与哪些因素有关系？

    A A combination of software algorithm, hardware PLL IC and carefully design of timestamping.tb_button {padding:1px;cursor:pointer;border-right: 1px solid #8b8b8b;border-left: 1px solid #FFF;border-bottom: 1px solid #fff;}.tb_button.hover {borer:2px outset #def; background-color: #f8f8f8 !important;}.ws_toolbar {z-index:100000} .ws_toolbar .ws_tb_btn {cursor:pointer;border:1px solid #555;padding:3px} .tb_highlight{background-color:yellow} .tb_hide {visibility:hidden} .ws_toolbar img {padding:2px;margin:0px}

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