眼图及眼图在信号测试中的运用

null眼图及眼图在串行信号测试中的运用眼图及眼图在串行信号测试中的运用DM高级应用工程师:黄腾 Email:thuang@tek.com www.tek.com眼图 分析 定性数据统计分析pdf销售业绩分析模板建筑结构震害分析销售进度分析表京东商城竞争战略分析 的原始驱动眼图分析的原始驱动通讯技术发展的需要 SONET和SDH的在广域传输中的广泛应用以及以太网技术的爆炸式应用和发展 电子系统从传统的并行总线转为串行总线 Highly Scable,Serial Interface 采用当前许多最新的通讯行业成熟应用的技术: Point to Point Interconect,Switch-based Technology, Packetlized Protocol 高速串行总线和传统并行总线对比高速串行总线和传统并行总线对比高速串行总线－新兴标准和数据速率高速串行总线－新兴标准和数据速率眼图定义眼图定义一般信号与眼图的区别一般信号与眼图的区别眼图特征定义眼图特征定义 眼图特征定义眼图特征定义眼图形成示意眼图形成示意眼图在示波器上的形成眼图在示波器上的形成眼图的CLK眼图的CLK采样示波器的CLK通常可能是用户提供的时钟,恢复时钟,或者与数据信号本身同步的码同步信号. 实时示波器通过一次触发完成所有数据的采样,不需附加的同步信号和触发信号.通常通过软件PLL方法恢复时钟.Tektronix RT-Eye软件即使用此方法. TDS8200 ET Scope (20GHz 80E03)TDS6154C RT w. DSP眼图与CLK－时钟速率提高,眼图质量下降眼图与CLK－时钟速率提高,眼图质量下降125M CLK250M CLK500M CLK示波器上的眼图示波器上的眼图提供串行总线数据的丰富信息:通过比较发送端和接收端的眼图质量可以分析出信号传输的问题 眼高,眼底,眼宽 上升时间 下降时间 模板 个人简介word模板免费下载关于员工迟到处罚通告模板康奈尔office模板下载康奈尔 笔记本 模板 下载软件方案模板免费下载 测试眼图与系统速率眼图与系统速率水平时域上关联因素 Transition (rise) time Aperture time Timing uncertainty, skew and jitter 垂直域 幅度损耗和噪声Unimpared bit edge眼图和传输质量眼图和传输质量Larger eye opening means greater tolerance to amplitude and timing variations Larger eye opening translates to simpler system design and better reliability Wider transition region indicates greater jitter and higher bit error rate Best error rate obtained when decision point is near center of the eye眼图测量特征量眼图测量特征量P ValuesPTopmean , the mean value of PTop PTopsigma , the standard dev of PTop PBasemean , mean value within aperture PBasesigma , std dev of PBase in aperture Pcrossmean , vertical mean of crossing pt.T ValuesTcrossmean , horiz mean of crossing pt. Tcrosssigma , horiz std dev of crossing pt. Tcrosspk-pk , horiz pk-pk of crossing pt.The Eye Aperture defaults to the center 20% of the interval from TCross1 to TCross2 but is settable from 0 to 100%null Jitter RMS = TCross1sigma Jitter Pk-Pk = TCross1pk-pk Extinction Ratio = PTopmean /PBasemean (ER also in dB and %) Quality Factor = (PTopmean-PBasemean)/(PTopsigma+PBasesigma) Eye Height = (PTopmean-3*PTopsigma)-(PBasemean+3*PBasesigma) Eye Width = (TCross2mean-3*TCross2sigma)-(TCross1mean+3*TCross1sigma) Crossing Percent, Duty Cycle Distortion, Noisepk-pk, NoiseRMS, SNR 眼图测量特征量眼图的测量眼图的测量 串扰 随机抖动 确定性抖动 码间干扰 (ISI) 占空比失真 (DCD) 正弦抖动 (SJ) 无关联的 幅度损耗远端采样点串行总线: Basic blocks串行总线: Basic blocksTransmittersInterconnects (paths)ReceiversDifferential TransmitterDual-coax differential cableTwisted-pair differential cableCoupled-pair traces on circuit board (backplanes)Differential Receiver高速串行总线－信号线上不仅包含数据信息还包含时钟信息高速串行总线－信号线上不仅包含数据信息还包含时钟信息pathDifferential serial data is sent without any clock signal across the interconnect to the receiverA clock is “recovered” from the incoming data at the receiver through a clock and data recovery circuit (CDR).高速串行总线－数据传输过程中干扰因素增多高速串行总线－数据传输过程中干扰因素增多Transition points often involve combinations of solder joints, circuit board vias, and connectors: these all can have substantial effect on the total link performance.高速串行总线－损耗 速率越高互连距离越长,损耗越大高速串行总线－损耗 速率越高互连距离越长,损耗越大Reference Maxim Note HFDN-27.0 (Rev. 0, 09/03)Clean, open, logical 1 & 0 at launch from transmitterSmeared edges at end of long interconnect.Logical 1 & 0 can be hard to distinguish at end of long interconnects; (this is often called a “closed eye”)Fast, sharp, edges at transmitter launch高速串行总线－串扰 高速串行总线－串扰 Serial data can be a single differential signal……but generally there are multiple “lanes” of serial data running side by side; these can CROSSTALK with each other.高速串行总线－精度 设计者要更加精确的掌控设计高速串行总线－精度 设计者要更加精确的掌控设计6.25Gb/s at Tx launch into backplane6.25Gb/s at 17in (43cm) of backplane6.25Gb/s after 34in (86cm) of backplaneSmall differences in levels being measured如何获得张开的眼图如何获得张开的眼图走线长度 短走线并非始终能够满足.短走线意味低损耗. 走线宽度 宽走线可以降低趋肤效应. 减小板材的介电常数 即降低介电损耗(Dielectric Loss),但将增加成本. 信号预加重和均衡处理 通过对跳变位预加重(Pre-Emphasis)处理补偿线路上因信号跳变产生的针对高频分量的损耗. 其它接收端均衡处理等. 眼图与BER眼图与BER究竟这个眼睛有多开? (…这却与你观察多久有关)?null眼图与BERpdf 1pdf 2cdf 20.5UI 12ABC0UI 1UI Eye open for BER @ 1.0E-12- 0.5UI 1.5UI cdf 11 1 0 眼睛睁开度 vs 误码率眼图与BER眼图与BER利用眼图分析抖动得到浴盆曲线(Bath Tub),从而进行误码率的估算。泰克提供的眼图测量 方案 气瓶 现场处置方案 .pdf气瓶 现场处置方案 .doc见习基地管理方案.doc关于群访事件的化解方案建筑工地扬尘治理专项方案下载 泰克提供的眼图测量方案从数据恢复时钟 (CDR), 眼图模板测试 硬件 CDR (PLL) 软件 CDR (PLL + 其它) 测量 绘图 抖动: 趋势, 频谱, 直方图, 浴盆曲线 硬件时钟恢复硬件时钟恢复TDS6000B 系列, TDS7704B 和 CSA7404B 显示器锗化硅触发 系统放大器/衰减器数据 采集 系统Golden PLL来自被 选中的 通道恢复 时钟Ch2 Ch3Ch4从1Mbit/s到 3.125Gbit/s的所有电接口和光接口速率独有的 锗化硅触发 系统硬件时钟恢复产生的眼图硬件时钟恢复产生的眼图TDS6804B/P7380SMA DSP增强功能 XAUI 超过 3.125Gb/s 眼图 测量 和统计新型测试方法 RT-Eye™方法生成眼图新型测试方法 RT-Eye™方法生成眼图新兴标准 要求 对教师党员的评价套管和固井爆破片与爆破装置仓库管理基本要求三甲医院都需要复审吗 新型工具 TDS RT-Eye (选项RTE)基于泰克在软件领域的专家经验，创建了一个交钥匙式的一致性测试和分析解决方案新型测试方法 RT-Eye™方法生成眼图新型测试方法 RT-Eye™方法生成眼图软件时钟恢复 眼图 全系列标准专用参数测量，包括幅度、定时和抖动 多种格线图，进行补充数据分析 标准专用模块作为插件提供 用户可定制的波形模板、测量极限和报告功能，支持专有标准和新兴标准 生成报告新型测试方法 RT-Eye™方法生成眼图新型测试方法 RT-Eye™方法生成眼图低抖动本底噪声 在TDS6604 或 TDS7704B上为700 fs RMS 单触发事件，而不是ET方法中的多触发事件 支持不同的时钟恢复模型 锁相环 (PLL) 相位内插重复取样 (恒定时钟, 连续位) 数据相关分析 把跳变位与非跳变位分开 码型长度检测，进行抖动分析 (Rj/Dj分离) 恢复高达 10Gb/s 的时钟 高达 5Gb/s 的眼图 高达 10Gb/s 的抖动分析 <0.1 UI的抖动本底噪声RT-Eye眼图示例－TDS6804B和下一代标准RT-Eye眼图示例－TDS6804B和下一代标准2.5Gb/s 5Gb/s 6.25Gb/s 新型测试方法 RT-Eye™方法生成眼图－分析结果 新型测试方法 RT-Eye™方法生成眼图－分析结果 新型测试方法 RT-Eye™方法生成眼图－抖动一致性测量 新型测试方法 RT-Eye™方法生成眼图－抖动一致性测量T TX-EYE-MEDIAN-to-MAX-JITTERTTX-EYE-MEDIAN-MAX-JITTER 新型测试方法 RT-Eye™方法生成眼图－抖动一致性测量 新型测试方法 RT-Eye™方法生成眼图－抖动一致性测量抖动眼图张开 + 总抖动 = 1UI采样示波器眼图生成采样示波器眼图生成When a clock signal is used to trigger the equivalent-time 8200 scope the sampled DATA signals generally create EYE PATTERNS (between clock triggers the sampled DATA could be either a logical 1 or 0)DatavoltagetimePrecision variable delayA clock trigger can be user-supplied or recovered from the data to trigger the equivalent time samplerClockEye patterns are the common result of clock-triggering in Equivalent time sampling: vectors are not drawn since adjacent samples can jump from logical 1 to 0 frequently采样示波器比较DRT示波器有更好的信号保真度采样示波器比较DRT示波器有更好的信号保真度CSA8200 with 20GHz 80E03A fast <15ps rising edge stimulus into an ET system and RT system; Averaging On. aberrations are listed

, step.DSP ONtR 10-90=22ps aberrPkPk=0%, 6.1%tR 10-90=30.3ps aberrPkPk=9.5%, 7.2%TDS6154C, DSP On.Averaging on采样示波器比较DRT示波器有更好的信号保真度采样示波器比较DRT示波器有更好的信号保真度CSA8200 with 20GHz 80E03 A fast <15ps rising edge stimulus into an ET system and RT system. aberrations are listed 
, step.TDS6154C, DSP On.DSP ONtR 10-90=21ps aberrPkPk=0%, 5.5%tR 10-90=22.5ps aberrPkPk=10.4%, 11.3%Averaging off采样示波器与DRT示波器眼图对比采样示波器与DRT示波器眼图对比TDS8200 ET Scope (20GHz 80E03)TDS6154C RT w. DSPAn Advantest 12Gb BERT (D3186) was used to differentially drive two channels and also supplied a reference clock.
LEFT:CHA-CHB on an TDS8200 with 80E03 20GHz sampler and an 82A04 Phase Reference module
RIGHT:CH2-CH3 on a TDS6154A (TDS6154C) realtime scope; eye generated using RT-Eye.采样示波器与DRT示波器眼图对比采样示波器与DRT示波器眼图对比TDS8200 ET 80E04TDS6154C RTO, DSP OnSlow Eye Diagram (4GFC, cca. 80ps edges, 600mV full swing)
(TDS6154 comparison is a composition)Mask Margin=80% Mask Margin=47% Mask_MarginCSA is about 1.7x Mask_MarginTDS应用对比选择应用对比选择TDS6154C
Debug
Triggering
Probing
Signal Acquisition
Single shot capable
Non-repetitive signals
Superior Advanced Analysis
Jitter
Serial Data Applications
Power, etc.TDS8200
Signal Fidelity
Bandwidth
Noise
Aberrations
Vertical & Horizontal resolution
TDR & TDR probing
Future Extendibility (Modular)
Optical SupportYour TurnYour TurnQuestions?
Concerns?
Suggestions?nullThank You For Attending!Mobile Phone:(0)13761684620光通信基础知识介绍-性能参数光通信基础知识介绍-性能参数光通信眼图比较关注的性能参数
          OMA(Optic Modulation Amplitude)和ER(Extinction Ratio)
          Q(Quality)
          OSNR(Optic Signal to Noise Ratio)
          Eye Opening/Eye Opening Penalty
          Bit Error Rate
          Reciver Sensitivity光通信基础知识介绍-性能参数光通信基础知识介绍-性能参数逻辑1和逻辑0:
            光功率高的状态是逻辑1，反之则为逻辑0.
            光功率常用:dBm = 10log10(Power(mW)/1(mW))
OMA:Optical Modulation Amplitude
            逻辑1和逻辑0光功率差:
            OMA=P1-P0
            有时也定义成:



ER:Extinction Ratio,消光比
光通信基础知识介绍-性能参数光通信基础知识介绍-性能参数另外一个重要术语就是Q.理论上系统的误码率BER是完全由光纤的信噪(Signal-to-Noise Ratio)比决定的,也就是Q.一般主要在光纤放大器和接收端进行测量.
光通信基础知识介绍-性能参数光通信基础知识介绍-性能参数OSNR:Optical Singal-to-Noise Ratio
                             
    对RZ编码传输系统,亦可定义如下:
                                                          
              和        定义如右图示

EOP:Eye Opening Penalty
      测量系统的垂直方向的眼图
      张开度,公式定义如下:

光通信基础知识介绍-性能参数光通信基础知识介绍-性能参数BER:Bit Error Rate
    
    
     与Q和OSNR或光功率相关,是衡量传输系统性能的最直观的特征.          当前光通信系统要求的BER一般在1E-9到1E-12之间.光通信基础知识介绍-SDH/SONET光通信基础知识介绍-SDH/SONETSONET:Synchronous Optical Network.北美标准.


SDH:Synchronous Digtial Hierarchy.欧洲标准.中国采用SDH标准.光通信基础知识介绍-SDH/SONET光通信基础知识介绍-SDH/SONET光通信基础知识介绍-SDH/SONET-光速率光通信基础知识介绍-SDH/SONET-光速率光通信基础知识介绍-SDH/SONET 眼图模板光通信基础知识介绍-SDH/SONET 眼图模板RatesX1X2Y1STM-1
OC-1 & OC-3STM-4
OC-9 to OC-240.150.350.200.250.400.20 STM-1,  STM-4 OC-1 to OC-24Normalized
AmplitudeTime (UI) 1+Y11-Y110.5Y10-Y1光通信基础知识介绍-SDH/SONET-Transmit Power Levels光通信基础知识介绍-SDH/SONET-Transmit Power Levels光通信基础知识介绍-SDH/SONET-Measuring Transmit Power光通信基础知识介绍-SDH/SONET-Measuring Transmit PowerOscilloscope with OE Converter
Limited Dynamic Range (0 to -35 dBm)
Accuracy adequate for some tests (error 6%, about ± 0.25dB)
Useful for troubleshooting functionality
Optical Power Meter
Extremely wide Dynamic Range (+10 dBm to -80 dBm)
Very accurate (error < 3%, about ± 0.1 dB)
Calibrated for multiple wavelengths
Useful for device calibration and accurately setting power levels光通信基础知识介绍-SDH/SONET-测试连接图光通信基础知识介绍-SDH/SONET-测试连接图Pattern GeneratorOptical SwitchOptical Power MeterO/E
Reference 
Receiver 

OscilloscopeApparatus:  Transmitter EvaluationData OutClock OutTrigger InSDUT光通信基础知识介绍-SDH/SONET Extinction Ratios光通信基础知识介绍-SDH/SONET Extinction Ratios光通信测量-CSA7000B光通信测量-CSA7000BOptical Bandwidth (unfiltered)CSA7404BElectrical BandwidthMaximum Real-time Sample RateTelecom/Datacom Bit Rates (max, filtered)Optical SensitivityWavelength RangeBase Price (USD)2.4 GHz4 GHz20 GS/s2.5 Gb/s-17 dBm700-1650 nm$63,250(AP504 CN Price)光通信测量-CSA7000B光通信测量-CSA7000B主要产品有CSA7154B,CSA7404B.
目前支持的最高速率为2.5Gb/s.
光通信测量-CSA7000B-ORR光通信测量-CSA7000B-ORR光通信测量-CSA7000B-ORR光通信测量-CSA7000B-ORR四阶Bessel-Thomson Filter 频响图,CSA7000B内嵌四阶Bessel-Thomson 数字滤波器.
可以保证用户在不同速率之间平滑切换.而无需
更换模块进行不同速率信号的测量.光通信测量-CSA7000B-ORR光通信测量-CSA7000B-ORR对NRZ编码光通信系统即通常的10Gb/s以下低速系统在接收端通常被设计成忽略高频上的细节,因为在高频上没有描述信号的重要参数.为了保持和真实接收端的一致性,内嵌的ORR带宽为0.75倍Bit Rate即1.5倍Bit Frequency.
对RZ编码而言,Bit Frequency等于Bit Rate,则根本没有ORR标准.甚至无法确定应该在什么频率上进行滤波,虽然看起来象应该高于Bit Frequency.这是由RZ编码的特点决定的.光通信测量-CSA7000B-Optical/Electrical System (ORR)光通信测量-CSA7000B-Optical/Electrical System (ORR)Waveform
Memory光通信测量-CSA7000B -Digital Filters -in the Optical Reference Receiver光通信测量-CSA7000B -Digital Filters -in the Optical Reference Receiver光通信测量-CSA7000B-ORR – Performance and Simplicity光通信测量-CSA7000B-ORR – Performance and SimplicityIntegrated Optical Reference Receiver (ORR)

Broad-wavelength, multimode O/E 700 to 1650 nm, calibrated at 780, 850, 1310,1550 nm

Library of ORR Digital Filters
4th-Order Bessel-Thompson filters
Easily disabled to provide full-bandwidth analysis on optical signals.
Eliminates the need for reconfiguring external accessories, modules or plug-ins

Allows easy optical/electrical Conformance Testing on a wide range of Comm standards up to 2.5 Gb/s with one instrument

Internal calibration ensures the accuracy and repeatability of results = confidence in measurements and design margins光通信测量-CSA7000B-Clock Recovery光通信测量-CSA7000B-Clock Recovery一个典型的SONET/SDH光纤传输系统收发单元示意图. 





The receiver's output interface provides regenerated data in a serial
		or parallel (deserialized) bit stream, along with the recovered clock.
在系统没有主时钟有效分布时需要采用Clock Recovery.
系统主时钟可以在研究室或机房等有效分配或布置.
分布式系统时钟(不同地点)可以用GPS接收机或时间-码产生机(time-code generators)进行同步(网络同步)  –称为1层时钟(Stratum 1 clocks) (highest level accuracy, synchronization).
Clock Recovery提供相对精度低点,低级别的同步(抖动, PLL 相关).光通信测量-CSA7000B-Clock Recovery光通信测量-CSA7000B-Clock RecoveryClock and Data Recovery (CDR) circuit functions:
First to recover the clock signal (CR) from the received data stream (input signal).
Use the CR to perform timing and amplitude-level decisions on the incoming signal.
Regenerate the data stream (DR), with timing and amplitude characteristics, synchronized with the recovered clock (CR) or regenerated system clock.
 Phase-Locked Loop (PLL) necessary for clock recovery:
Fully integrated and does not require an external reference clock. 
Ensure alignment of the clock with the middle of a data word.
Monitors the CR and provides a Loss-of-Lock (LOL) alarm when the PLL loses lock.
for Optimized bit error rate (BER) – adjust clock phase relative to the data signal.Jitter specifications – the real challenge for integrated CDRs:
Jitter specifications are recommended by the ITU/ Bellcore – e.g.  The OC-48, 2.488 Gb/s specs transmitter jitter-generation of 0.01 UIRMS (4 psRMS) and receiver jitter tolerance of 0.15 UIPk-Pk (60 psPk-Pk).  One bit Unit-Interval (UI) = 1/2.488Gb/s = 400 ps.
“Eye diagrams" best illustrate the signal quality of a serial data stream – this can be done directly (Measurements) or referenced to an "eye mask“ (Mask Test).光通信测量-CSA7000B-Clock Recovery光通信测量-CSA7000B-Clock RecoveryCSA7404B – Built-in CR for optical and electrical serial data streams from 1.5 Mb/s to 2.5 Gb/s
Integrated CR in an oscilloscope
Provides single-connection convenience
Can be used internally for trigger pick-off
Improves internal jitter performance
Eye diagram analysis and mask test with more confidence
Jitter and pattern dependencies are not hidden by triggering on the data stream
CR and DR Outputs (on CSA7000s only) 
Max 1.25 Gb/s CR and DR on outputs
Recovered Clock Out (CR) and Regenerated Data Out (DR) from specified channel, available on SMA front-panel connectors for use with other test equipment (e.g. BER analyzers)