Correlation is an important concept which appears in two separate contexts in jitter analysis. For ddj jitter measurements, the measurement bandwidth should. The ddj relates to the system bandwidth, the bit rate, the input risefall time, and the number of maximum consecutive identical bits of the data pattern. The ui is the proportion of jitter per bit and is calculated using eq. A repeating prbs9 pseudorandom test pattern, 511 bits long, is used. Data jitter is thedeviationof thedata threshold crossing times from a reference time. Abstractan analysis for calculating datadependent jitter. Pdf analysis and equalization of datadependent jitter. The impact of jitter on conventional clock and data recovery circuits is studied in the time and frequency domain. These protocols use dynamically changing duty cycles and irregular clock edges, which contribute to overall jitter. This is the pdf is assumed to be the pdf for each and every edge in the pattern.
As well as expressing the amount of jitter in time units, such as ps and ns, jitter can also be expressed as the unit interval ui. Effect of prbs pattern length on datadependent jitter. The simulation results show that ddj is dependent on the data pattern, data rate, and data slew as well as frequency bandwidth, impedance mismatch, and loss of the data path of integrated circuits. The integrated decay electron distribution in the lab frame has the form n idealt n 0 exp. A jitter test is a type of network performance test that helps to evaluate and measure the rate and statistics of network jitter based errors and latency. The rfd sends two sets of pulses using nodes up and dn. A perturbation technique is used to generalize the analytical. Timing jitter consists of random jitter rj and deterministic jitter dj. For a clock signal, the pdf consists of two impulse. Jitter measurements in serial data signals teledyne lecroy. Jitter stew jitter can best be defined as the sum total of skews, reflections, patterndependent interference, propagation delays, and coupled noise that degrade signal quality.
Quality phone calls require a jitter rating of less than 1520ms. As a result, this numeric simulation only considers ddj. Clock jitter cancelation in coherent data converter. Jitter stew basically represents the portion of a unit inter. The implemented prototype in 65nm cmos supports both 10gbs nrz and 20gbs pam4 while. Duty cycle distortion and intersymbol interference are good examples of the system memory, this means, that the current bit waveform will depend from the previous bits. Wavepro 7 zi series test equipment pdf manual download. Page 178 menus and dialog boxes jitter measurements panel optional. This paper presents a closedform equation of data dependent jitter ddj in first order low pass systems. The peaktopeak amplitude for the component of the deterministic jitter correlated with the signal polarity. Pragmatic simulationbased verification of clock domain crossing signals and jitter using systemverilog assertions mark litterick, verilab, munich, germany. This is referred to as data correlated jitter, and it is simply characterized by frequency bandwidth limited model or transmission line. Jittering to prevent overplotting in statistical graphics.
Datadependent jitter of transmitter for nonframed prbs and sdhframed signal weresimulated. We could use any berr but 1012 is quite common to use and 1012 equals to 14. The total jitter is modeled as the sum of two independent random variables, rj, and dj, 1 as follows. Lastly, the other type of data dependent jitter is due to variations in the crossing level used to identify the edge timing, an offset in the signal amplitude, or asymmetry in risefall times. However, this jitter is correlated to the data pattern, and is therefore data dependent jitter. A more appropriate jitter definition would seem to be one for something called jitter stew. Removing dj would produce a gaussian distribution adding dj to the histogram broadens the distribution while maintaining gaussian tails, effectively separating. A preliminary pair of rj and dj are determined, and from these an idealized probability density function pdf is calculated. Datadependent jitter ddj is an important component of dj, which characterizes the delay deviation among different data patterns. Dj can be further classified into three subcategories.
The response is determined by both current state and previous state of data 45. The m28335 is a 12port line interface unit liu which includes integrated receivers and transmitters for use in implementing digital loop carriers dlcs,digital subscriber line access multiplexers dslams,multiservice access concentrators,and packet and atm cell switches. Understanding jitter, its components, and separation. Jitter objects make extensive use of a new max capability known as attributes. If random jitter is excessive, other means of jitter cleaning may be needed for example, use of retimers.
Depending on characteristics of the signal and transmission topology, previously transmitted symbols can affect the edge cross over time. However, system timing margins are degraded by channel skew between clock and data signals and highfrequency loss. Pdf datadependent jitter in serial communications researchgate. A method for calculating the data dependent jitter in broadband systems from the pulse response is discussed. Measuring deterministic jitter tj histograms represents the tj pdf, therefore if the dj and rj process are independent the total pdf is the convolution of the dj and rj pdf. Data dependent jitter measurement varies by system.
Data dependent jitter ddj ddj is a part of deterministic jitter dj, and consists of dcd and isi. Highspeed links which employ source synchronous clocking architectures have the ability to track correlated jitter between clock and data channels up to high frequencies. Final report of the muon e821 anomalous magnetic moment. Of these, ddj is impacted directly by the data pattern. First, the data depen dent jitter ddj due to the transmission line is analyzed and a ddj probability density knction pdf is intro duced. Example waveform of simple data dependent jitter ddj.
Ddjs pdf is always a series of pulses at the locations where a specific bit pattern experiences a cross over. Datadependent jitter in serial communications ieee xplore. Clock and data recoveryintroductionjitter is far from. Pdf measurements of fission fragment properties using. For an explanation of attributes, you should first read the chapter titled attributes that precedes the jitter tutorial in the jitter manual jittermanual. Dda 7 zi series, sda 7 zi series, wavepro dda 7 zi series, wavepro sda 7 zi series. For the 001 and 101 sequences, the firstorder ddj pdf consists of a double dirac function as modeled in 1. Data dependent jitter buj bounded uncorrelated jitter dcd duty cycle distortion isi inter symbol interference l 1 l 2 ddpws data dependent pulse width shrinkage. Sinusoidal jitter is best for modeling, for measuring and to retain some margin, but real jitter is essentially noisy some periodicity in the bit stream due to framing, or to periodic data patterns, may induce via intersymbol interference periodic components of jitter, but the real jitter will be essentially noisy.
Deterministic jitter dj is the type of jitter that is bounded has a finite peaktopeakvalue, repeatable and predictable. Another common name for ddjisi is pattern dependent jitter pdj. Furthermore, random jitter is the type of jitter lvds signal conditioners cannot eliminate or minimize. When two or more random jitter sources are added in the signal path, their random jitter contributions are summed geometrically. How the dependent method obtains this update data is configured by the parameters with which the method is called.
The standard jitter measurement is in milliseconds ms. The jitter probability density function the jitter probability density function pdf gives the probability for a given logic transition to differ from the ideal by certain amount between. Pdf datadependent jitter limits the biterror rate ber performance of broadband communication systems and aggravates synchronization. Estimating datadependent jitter of a general lti system from step response behnam analui, james buckwalter, and ali hajimiri abstract we present a method for estimating data dependent jitter ddj introduced by a general lti system, based on the systems step response. Characterizing jitter histograms for clock and datacom. Estimating datadependent jitter of a general lti system from. Most jitter objects are considerably more complex than most other max objects. Nov 14, 2019 the longer data packets take to transmit, the more jitter affects audio quality. The results showed that jitter evaluation for transmitters should be identical to the framed pattern used at the final equipment testing. This paper describes how these key channel effects impact the jitter performance and influence the clocking. Dj has systematic origins such as bandwidth limitation or crosstalk. The input is the reference 25mhz signal, compared with the feedback from the frequency divider, both are entering pfd. Data dependent jitter ddj is a specific class of timing jitter.
We would like to show you a description here but the site wont allow us. Analysis and equalization of datadependent jitter article pdf available in ieee journal of solidstate circuits 4. Probabilistic theory for semiblind oversampling burst. If receiving jitter is higher than 1520ms, it can increase latency and result in packet loss, causing audio quality degradation. A new jitter model is developed using matlab and spice to analyze data dependent jitter ddj in serial data integrated circuits. Data dependent jitter, a prominent form of the deterministic jitter of data symbols, arises from the impairment of channels and is a major contributor to isi 51. So if we measure sigma is 10 picoseconds, then we would say the random jitter is 141 psec. Jitter tests help in identifying the amount of jitter present on a network connection or infrastructure. Measurements are able to estimate the jitter pdf, but are not able to determine the. High speed interconnect data dependent jitter analysis. Deterministic jitter dj is predictable, bounded, and is attributed to duty cycle distortions.
Pdf we present a method for predicting datadependent jitter ddj introduced by a general linear timeinvariant lti system based on the. The predicted ddj features unique threshold crossing times with selfsimilar geometry. The dcd pdf probability density function is represented by two. Delay jitter control for realtime communication in a packet.
In compiler theory, the technique used to discover data dependencies among statements or instructions is called dependence analysis. View and download lecroy wavepro 7 zi series operators manual online. This assumes that the gaussian rj pdf appends to the dj pdf. The fission fragment nuclear charge distributions can be determined and a timing signal can be extracted which allows a determination of the instant of fission with a time jitter of jitter. It directly equalizes data dependent jitter ddj by adaptively shifting the isiaffected zero crossings. Receiver jitter tracking characteristics in highspeed source. This type of impairment is dutycycle distortion dcd. A combined clock and data recovery circuit with adaptive. Proposed data dependent jitter ddj measurement ieee 802. Datadependent jitter ddj is a specific class of timing jitter. Analyzing digital jitter and its components 4 12 page 23 automated jitter analysis page 24 advanced jitter analysis use counter hardware to focus samples on edges use averaging to isolate datacorrelated jitter focus on individual edges to isolate datauncorrelated jitter datacorrelated jitter is data dependent jitter ddj. In particular, it is a form of deterministic jitter which is correlated with the sequence of bits in the data stream.
A newly introduced method called normalized qscale analysis offers a more robust, repeatable, and accurate technique to estimate and measure the random and bounded, uncorrelated jitter compo. Since rj and ddj are independent, the total jitter pdf is the con volution of. Datadependent jitter in serial communications core. The data dependent jitter of a interconnect on fr4 board with various line separations. Delay jitter control for realtime communication in a packet switching network dinesh c. They help in understanding how quickly packets are arriving at the. The deterministic nature of data dependent jitter suggests equalization techniques suitable for highspeed. To confirm the derived equation, simulations have been done with a first order rc low pass circuit for various system bandwidths, bit.
Dj can be subdivided further into data dependent jitter ddj and periodic jitter pj. In contrast, intersymbol interference isi is an example of data dependent jitter from an isochronous 8b10b coded serial data stream e. Generally two random variables are correlated if changing one of the variables causes the other to change. Predicting datadependent jitter article in circuits and systems ii. Pragmatic simulationbased verification of clock domain. Using clock jitter analysis to reduce ber in serial data. To a statistician, it is more than what happens when you drink too much coffee. Jittering is the act of adding random noise to data in order to prevent overplotting in statistical graphs. The jitter components of a data signal can be classified into deterministic jitter dj and random jitter rj. The fomc moved to data dependent forward guidance in december 2012, when it replaced the calendar date with the socalled thresholds for inflation 2.
An1957lvds signal conditioners reduce data dependent jitter. Clock jitter cancelation in coherent data converter testing. Datadependent jitter and crosstalkinduced bounded uncorrelated jitter in copper interconnects james buckwalter, behnam analui, and ali hajimiri california institute of technology, pasadena, ca 91125 abstract this paper resolves the jitter impairment of nonreturntozero data in transmission lines. Closedform equation of data dependent jitter in first order. This is basically random jitter with a bounded pdf. Random jitter is unbounded, if we wait long enough we would have hits anywhere in the eyediagram. Designcon 20 understanding apparent increasing random. Predicting datadependent jitter james buckwalter, student member, ieee, behnam analui, student member, ieee, and ali hajimiri, member, ieee abstractan analysis for calculating datadependent jitter ddj in a. However, language about being data dependent remained in.
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