An eye diagram is a useful tool for understanding signal. Seamlessly integrates into teledyne lecroys sda ii software for eye diagram and jitter analysis. The vertical axis in the 2d statistical eye diagram is in codes, not millivolts. Simulated eye diagrams for internal and external lpddrs under ff and ss corners. You can easily see the noise margins of the data signal with an eye diagram. Digital signal integrity the eye diagram is also a common indicator of performance in digital transmission systems. The mp1800a is a multichannel bert with 32 channels max. What does an eye diagram or eye pattern on an oscilloscope mean. Ideal high speed digital signal with eye diagram obviously, this ideal eye diagram offers little additional information beyond the time domain waveform display. Simbeor is the onestop solution for all interconnect budget exploration advanced stackup planning and prelayout, design verification. Simbeor is the onestop solution for all interconnect budget exploration advanced stackup planning and pre.
Vital for anyone using an 8 ghz or higher oscilloscope. Noise margin refers to the amount by which the signal for 0 or 1 exceeds ideal boundaries but is still within an acceptable range. By applying a mask test to the composite eye diagram, you can quickly tell if the signal can meet the overall signalintegrity requirement. With comprehensive jitter and eyediagram analysis and decomposition algorithms dpojet simplifies discovering signal integrity concerns and jitter and their related sources in todays highspeed serial, digital, and communication system designs. The everchanging hardware that supports big data and the internet of things must be fast, reliable and quickly developed.
The all eye diagrams graph is used as a collection document. The highfrequency performance of the pcb was improved, and the potential signal. For comparisons, please see the all eye diagrams graph, described below. As shown in figure 4, the resulting waveform resembles an eye, hence the. Review of signal integrity concepts at frequencies in the gigahertz range, a host of variables can affect signal integrity. Jitter analysis includes standard tj, rj and dj dualdirac model measurements, jitter spectrum, jitter histogram and more. Electronics free fulltext design and realization of a. Does the signal reach its destination when it is supposed to. Highspeed board designers have come to rely upon the venerable ipcd317, design guide for electronic packaging utilizing highspeed techniques in the design of their highspeed circuitry. Eye diagram and digital signal testing national instruments. Users can measure the sparameters on an attached lecroy sparq signal integrity network analyzer, or import a touchstone file from a vna or other sparameter modeling or simulation tool. Maintaining power and signal integrity by larry zu, president, sarcina technology llc, palo alto, u. Cool 3d visualization capabilities for eye diagram analysis that will captivate anyones attention ddrx wizard supports new architectures for lpddr and registered dimms thats just a few of the things youll find in hyperlynx 8.
In the design of highspeed digital circuit, the transmission of digital signal by the differential pair can solve signal integrity issues effectively. Eye diagram analysis in simbeor thz wild river technology. Eye diagram measurements in ads the use of optimization in signal integrity performance centric high speed digital design flow brahim bensalem, intel corporation lihua wang, agilent technologies sanjeev gupta, agilent technologies. Eye diagrams are a quick, visual means to quickly identify whether there are any signal integrity issues before moving on to more refined analysis. The duration of the eye diagram is 268 ps, about 34% greater than the 200 ps clock period, letting two adjacent eye crossings be visible at once. Understanding data eye diagram methodology for analyzing high speed digital signals introduction the data eye diagram is a methodology to represent and analyze a high speed digital signal. Hyperlynx signal integrity delivers advanced tools for optimizing serdes design projects. Dpojet provides the highest sensitivity and accuracy available in realtime instruments. Makers of digital communications hardware often include eye diagrams in their literature to demonstrate the signal integrity performance of their products. Differential signals offer superior noise immunity and overall improved signal integrity, which is highly desirable in. In telecommunication, an eye pattern, also known as an eye diagram, is an oscilloscope display in which a digital signal from a receiver is repetitively sampled and applied to the vertical input, while the data rate is used to trigger the horizontal sweep. May 30, 2017 since the eye diagram is derivative of the received signal, there is no new information between the eye diagram and the received signal. Signal integrity design using fast channel simulation and. I spy with my little eye a signal integrity issue keysight.
The basics of signal integrity analysis in your pcb pcb. What does an eye diagram or eye pattern on an oscilloscope. Hyperlynx business and technical value technology overview. The greater the area of the eye opening the better the channel signal integrity. It is so called because, for several types of coding, the pattern looks like a series of. The correlation display analysis function of the eye diagram is shown in figure 8, including eye diagram display, mark testing, eye diagram parameter calculation. Aug 01, 2014 this video demonstrates the what if design space exploration workflow that our statistical eye diagram channel simulator enables, and also covers tools and modes that can be used in exceptional. Standard eye diagram simulation mentor graphics communities. Fundamentals of signal integrity analysis watch for more ways to get started with signal. Accurate signal integrity analysis results product demo. Once the eye diagram is created, we can look at its pattern and determine the quality. The bottom trace is the eye diagram for a data stream clocked at 5 ghz. Eyediagram analysis speeds ddr sdram validation electronic. This is because the fast edge rate at ff wafer corner introduces higher ripples.
As a result, the eye diagrams are dramatically worse than the ss slow ptype and slow ntype transistors corner. Differential signals use a true p and a complement n signal, one being an inversion of the other. Pcba reliability due to thermal cycling and shock power integrity. Eye diagrams are powerful representations of serial signals. Now lets move the probes of the oscilloscope to the other, poorly designed, connection and repeat the simulation.
The eye diagram displays multiple data bits using a duration of slightly longer than a single bit period on a persistence display. The use of optimization in signal integrity performance. Uses industry standard touchstone format sparameter files for fixture and channel. Figure 4 an eye diagram can help you interpret a signal and determine the best time for making a measurement. Signal integrity analysis of package and pcb for high speed. Simbeor is the industryfirst measurementvalidated electromagnetic signal integrity software for physical design of pcb and packaging interconnects for communication links operating at 6100 gbs and beyond. Eyediagram system object, eyediagram function, or eye diagram scope block to examine the eye diagram of signals for information about constructing an eye diagram object, running a simulation, collecting data. When testing ddr interface signal quality, data eye analysis helps to reveal potential. With eye diagrams you can see signal quality with one display, you can diagnose problems, such as attenuation, noise, jitter, and dispersion that arise or characterize specific parts of the system. This eye diagram is completely unacceptable the signal enters prohibited areas of the mask. Signal integrity design using fast channel simulation and eye. This video demonstrates the what if design space exploration workflow that our statistical eye diagram channel simulator enables, and also covers tools and modes that can be used in exceptional. Jitter, noise and eyediagram analysis solution tektronix. Eye diagram measurements in ads the use of optimization in signal integrity performance centric high speed digital design flow brahim bensalem, intel corporation lihua wang, agilent technologies.
Singleended eye diagrams were successfully formed at 5 gbitssec. A closed eye indicates signal integrity degradation. Signal integrity analysis of package and pcb for high speed data link application by sreejith palleeluveedu raghavan department of electrical and information technology faculty of engineering, lth, lund university se221 00 lund, sweden. The eye diagram allows key parameters of the electrical quality of the signal to be quickly visualized and determined.
Simbeor is the onestop solution for all interconnect budget exploration advanced stackup planning and prelayout, design verification postlayout, dielectric and conductor roughness models identification, and macromodeling tasks. Sdaiiicompletelinq software for eye diagram and jitter analysis. However, the eye diagram allows us to have a concise way to view the quality of the interconnect in a single picture. The detection of other parameters mentioned in the paper can find the corresponding function in the board of clock recovery, jitter measurement, level detection, jitter signal.
Eye diagrams provide instant visual data that engineers can use to check the signal integrity of a design and uncover problems early in the design process. Ensuring high signal quality in pcie gen3 channels 2017. By varying the data rate of the digital data the different structures can be compared to see how they. As data rates and design complexity continues to increase, signal integrity becomes an integral part of the design. One of the most fundamental measurements used in digital systems, particularly in gigabit. Simulation tools are great for calculating the behavior of signals in different nets during schematic and layout design, but youll still need to take some steps to interpret the results. Programmable software clock recovery including software pll 1. The attached graphs show the associated eye diagrams. Since the eye diagram is derivative of the received signal, there is no new information between the eye diagram and the received signal.
Understanding eye pattern measurements application note. The signal integrity analysis of differential signal based on. An ideal digital waveform with sharp rise and fall times and constant amplitude will have an eye diagram as shown in figure 1 below. Simulated eye diagram dislplaying a ddr3 signal waveform.
When evaluating digital signals, the eye diagram will be nearly square. Signal integrity analysis and measurements go handinhand. Developing customized measurements and automated analysis. A pure software based ddr3 signal eye diagram test method is used to verify the improvement inf the signal integrity of the chip without the need for probe measurement. It does this by using the xilinx hardware described above, using an hdllinux reference design that was created by analog devices.
Mar 10, 2017 the purpose of the eye diagram is to witness at a glance the health of the signal integrity. The signal integrity analysis of differential signal based. The most popular formats for high speed electrical circuits are nonreturn to zero nrz and pulse amplitude modulation with 4 levels pam4. In digital communications, an eye diagram provides a visual indication of how noise might impact system performance. Eye patterns an eye diagram is the result of superimposing the 1s, 0s and corresponding transitions of a high speed digital signal onto a single amplitude, versus time display. Several software tools available at present for signal integrity analysis and current trends in this area will also be introduced. The software rapidly analyzes eye diagram behavior and jitter decomposition characteristics of a serial data channel. In actuality, the ss corner has the best eye diagrams, even better than those of the tt typical p and ntype transistors. Compliance and signal integrity analysis of automotive. The basics of signal integrity analysis in your pcb pcb design. The jesd204b eye scan tool that analog devices created runs natively on a the zc706 under linux and creates the pictures below. The model was then ported to ansys hfss to provide a fullwave sparameter model for simultaneous noise switching analysis. Histograms are used to statistically analyze time and. However, digital signals are fundamentally analog in nature, and all signals are subject to effects such as noise, distortion, and loss.
Ability to execute your matlab analysis routines directly on agilent oscilloscopes using n8806a udf visualizing analysis routines to improve signal integrity analysis routines created in matlab can be utilized to visualize and understand eye diagram characteristics to help improve signal integrity of your highspeed systems. The channel combines the em extracted data of the connector, eightlane channel and chip package in advanced design system ads software. Differential eye diagrams were successfully formed at 5 gbitssec. Analysis to measurement correlation of eye diagram for pcb interconnects in simbeor thz electromagnetic signal integrity software. Singularity engineering provides a unique set of solutions to predict and solve a wide range of problems for electronics systems.
Jitter, emphasis and pam ber functions support accurate signal integrity analysis for phy devices such as serdes, highspeed interconnects such as aoc qsfp for infiniband, as well as for 100 gbedpqpsk optical modules. This software allows the system to operate similar to a highspeed sampling. I think eye diagrams are covered in chapter seven white paper. Creates eye diagrams 50x faster than existing solutions.
Creating eye diagrams using vectorstar snp files and awr. With comprehensive jitter and eye diagram analysis and decomposition algorithms dpojet simplifies discovering signal integrity concerns and jitter and their related sources in todays highspeed serial, digital, and communication system designs. The method of increasing the thermal conductive silver glue was used to improve the thermal performance after the test and analysis. Syz parameter extraction, serdes and eye diagram calculation electronics cooling.
Ease of use let engineers focus on analyzing their designs rather than learning how to use test equipment. One tool used to characterize these effects is the eye diagram. This instrument class measures samples of the input signal to form an eye diagram that can be used for analysis of the signals noise, jitter, and eye mask compliance. Analysis options scale from timing standard, to jitter opt. Eye pattern fundamentals an eye diagram is a useful tool for understanding signal impairments in the physical layer of highspeed digital. Confidence in measurement results repeatability from one test system to the next.
Feb 24, 2016 analysis to measurement correlation of eye diagram for pcb interconnects in simbeor thz electromagnetic signal integrity software. It is so called because, for several types of coding, the pattern looks like a series of eyes between a pair of rails. Making use of an actual pcb, its signal integrity and eye diagram performances were simulated by the hyperlynx software. Signal integrity analysis of package and pcb for high. To generate a waveform analogous to an eye diagram, we can apply infinite persistence to various analog signals a well as to quasidigital signals such as square wave and pulse as synthesized by an arbitrary frequency generator afg. From the eye diagram, it can be seen that the signal degrades over a long transmission path and due to the connectors. This eye diagram represents an excellent signal integrity. The ability to accumulate and display samples supports statistical analysis techniques for assessing the quality of the digital signal, but does not detect. The purpose of the eye diagram is to witness at a glance the health of the signal integrity. An eye diagram is used in electrical engineering to get a good idea of signal quality in the digital domain. Eye diagrams help with the effective analysis of serial data, and offer both qualitative and quantitative insight regarding the data communications signal path itself and what might be affecting signal integrity. Teledyne lecroy serial data standard eye doctor ii. This measurment is also called the eye diagram or signal integrity test. The eye diagram is the digital measurement that most signal integrity engineers are familiar with today and can have various formats.
Find and fix weaknesses in ddr234 and lpddr234 designs with just a few clicks using the ddrx wizard. Dpojet is the premier eyediagram, jitter, noise and timing analysis package. The basics of signal integrity analysis in your pcb can be anything but basic. As discussed above, the 2d eye scan operates after the agc and equalizer blocks inside the fpga, so it is difficult impossible to correlate voltage on the rx pins of the fpga, to the vertical axis in the 2d statistical eye diagram. If the eye diagram shows an open eye at the transmitter and a closed eye at the receiver, the next step is to determine which devices or interconnects in the channel are causing the signal degradation. In digital electronics, a stream of binary values is represented by a voltage or current waveform. And9075 understanding data eye diagram methodology for. Dec 16, 2011 figure 4 an eye diagram can help you interpret a signal and determine the best time for making a measurement. This technology offers great immunity from commonmode noise, and yields excellent signal integrity provided that uniform impedance is achieved and that the pair of signals arrive at the receiver simultaneously. The following is a simplified block diagram of the eye diagram creation process. Additive noise tends to close the eye vertically while timing jitter. A rich set of jitter and eye diagram analysis tools yield deep insight signal integrity issues of. Coupled with the automated passfail eye diagram mask testing capability of the jitter analysis application, this graphical measurement technique allows you to use a single test to verify signal amplitudes and noise, timing jitter, and rise and falltimes. The agilent 71501d eyediagram analysis you can configure the 71501d system as a highspeed eyediagram analyzer using option 005 eyediagram analysis software.
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