公开(公告)号：US20070133726A1

公开(公告)日：2007-06-14

申请号：US11228664

申请日：2005-09-15

申请人： Srikrishna Nadig ,  Kalev Sepp

发明人： Srikrishna Nadig ,  Kalev Sepp

IPC分类号： H04L7/02

CPC分类号： H04L7/0058 ,  H03L7/00 ,  H04L1/205 ,  H04L7/033

摘要： A method for recovering a clock from a serial data stream for use in producing “eye” diagram measurements includes determining an initial recovered clock from the serial data stream based upon transition edges. Time interval error values are then determined as a function of the transition edges and corresponding initial recovered clock times. Time interval error values are interpolated for initial recovered clock times not associated with transition edges to produce a complete set of time interval error values. The complete set of time interval error values are lowpass filtered to produce a filtered set of time interval error values. The clock for the serial data stream is reconstructed from the filtered set of time interval error values.

摘要翻译： 用于从用于产生“眼”图测量的串行数据流中恢复时钟的方法包括基于过渡边缘确定来自串行数据流的初始恢复时钟。 然后，确定时间间隔误差值作为过渡边缘和对应的初始恢复时钟时间的函数。 对于与过渡边缘无关的初始恢复时钟时间，内插时间间隔误差值，以产生一整套时间间隔误差值。 完整的一组时间间隔误差值被低通滤波，以产生经滤波的一组时间间隔误差值。 串行数据流的时钟从经过滤的一组时间间隔误差值重建。

公开(公告)号：US20080080605A1

公开(公告)日：2008-04-03

申请号：US11529856

申请日：2006-09-28

申请人： Kan Tan ,  John C. Calvin ,  Kalev Sepp

发明人： Kan Tan ,  John C. Calvin ,  Kalev Sepp

IPC分类号： H04B3/46

CPC分类号： H04L1/205 ,  G01R29/26 ,  G01R31/31709

摘要： A method of measuring transport delay and jitter with a realtime oscilloscope using cross-correlation acquires waveforms from two test points in a system under test. Clock recovery is run on both waveforms to obtain respective rates and offsets. A time offset between the two waveforms is computed. The jitter from the two test points is filtered and a mean-removed cross-correlation coefficient is computed from the filtered jitters. A fractional delay is computed using interpolation based on LMS error, and the respective computational components are summed to compute a transport delay between the two test points. The transport delay may be used to adjust clock edges from one waveform for comparison with data transition edges of the other waveform to measure jitter.

摘要翻译： 使用互相关的实时示波器测量传输延迟和抖动的方法从被测系统的两个测试点获取波形。 在两个波形上运行时钟恢复以获得相应的速率和偏移量。 计算两个波形之间的时间偏移。 对两个测试点的抖动进行滤波，并从滤波的抖动中计算平均去除的互相关系数。 使用基于LMS误差的插值计算分数延迟，并将相应的计算组件相加以计算两个测试点之间的传输延迟。 传输延迟可用于从一个波形调整时钟边沿，以便与其他波形的数据转换边沿进行比较，以测量抖动。

公开(公告)号：US07912117B2

公开(公告)日：2011-03-22

申请号：US11529856

申请日：2006-09-28

申请人： Kan Tan ,  John C. Calvin ,  Kalev Sepp

发明人： Kan Tan ,  John C. Calvin ,  Kalev Sepp

IPC分类号： H04B3/46

CPC分类号： H04L1/205 ,  G01R29/26 ,  G01R31/31709

摘要： A method of measuring transport delay and jitter with a realtime oscilloscope using cross-correlation acquires waveforms from two test points in a system under test. Clock recovery is run on both waveforms to obtain respective rates and offsets. A time offset between the two waveforms is computed. The jitter from the two test points is filtered and a mean-removed cross-correlation coefficient is computed from the filtered jitters. A fractional delay is computed using interpolation based on LMS error, and the respective computational components are summed to compute a transport delay between the two test points. The transport delay may be used to adjust clock edges from one waveform for comparison with data transition edges of the other waveform to measure jitter.

摘要翻译： 使用互相关的实时示波器测量传输延迟和抖动的方法从被测系统的两个测试点获取波形。 在两个波形上运行时钟恢复以获得相应的速率和偏移量。 计算两个波形之间的时间偏移。 对两个测试点的抖动进行滤波，并从滤波的抖动中计算平均去除的互相关系数。 使用基于LMS误差的插值计算分数延迟，并将相应的计算组件相加以计算两个测试点之间的传输延迟。 传输延迟可用于从一个波形调整时钟边沿，以便与其他波形的数据转换边沿进行比较，以测量抖动。

公开(公告)号：US07623581B2

公开(公告)日：2009-11-24

申请号：US11228664

申请日：2005-09-15

申请人： Srikrishna H. Nadig ,  Kalev Sepp

发明人： Srikrishna H. Nadig ,  Kalev Sepp

IPC分类号： H04L12/28 ,  G01R13/00

CPC分类号： H04L7/0058 ,  H03L7/00 ,  H04L1/205 ,  H04L7/033

摘要： A method for recovering a clock from a serial data stream for use in producing “eye” diagram measurements includes determining an initial recovered clock from the serial data stream based upon transition edges. Time interval error values are then determined as a function of the transition edges and corresponding initial recovered clock times. Time interval error values are interpolated for initial recovered clock times not associated with transition edges to produce a complete set of time interval error values. The complete set of time interval error values are lowpass filtered to produce a filtered set of time interval error values. The clock for the serial data stream is reconstructed from the filtered set of time interval error values.

摘要翻译： 用于从用于产生“眼”图测量的串行数据流中恢复时钟的方法包括基于过渡边缘确定来自串行数据流的初始恢复时钟。 然后，确定时间间隔误差值作为过渡边缘和对应的初始恢复时钟时间的函数。 对于与过渡边缘无关的初始恢复时钟时间，内插时间间隔误差值，以产生一整套时间间隔误差值。 完整的一组时间间隔误差值被低通滤波，以产生经滤波的一组时间间隔误差值。 串行数据流的时钟从经过滤的一组时间间隔误差值重建。

公开(公告)号：US06836738B2

公开(公告)日：2004-12-28

申请号：US10389545

申请日：2003-03-14

申请人： Kalev Sepp ,  John C. Calvin

发明人： Kalev Sepp ,  John C. Calvin

IPC分类号： G01R2902

CPC分类号： G01R13/029

摘要： A first method for rendering an eye diagram synchronized to a recovered clock and based on a single shot acquisition of a digital storage oscilloscope, acquires a waveform and measures the timing of its edges. It then estimates the symbol rate of the waveform and derives clock signals in accordance with the edge timing and the estimated symbol rate. The waveform data is then sliced into frames with respect to the derived clock signals, and the frames are partially overlapped and aligned to form an eye diagram. In a second embodiment of the invention, the frames are aligned, without being overlapped, to form an eye diagram.

摘要翻译： 用于渲染与恢复的时钟同步并基于数字存储示波器的单次采集的眼图的第一种方法，获取波形并测量其边缘的定时。 然后，它估计波形的符号率并根据边沿定时和估计的符号率导出时钟信号。 然后将波形数据相对于导出的时钟信号切片成帧，并且将帧部分地重叠并对准以形成眼图。 在本发明的第二实施例中，框架被对准而不重叠以形成眼图。

公开(公告)号：US20090121762A1

公开(公告)日：2009-05-14

申请号：US11937749

申请日：2007-11-09

申请人： Kalev SEPP

发明人： Kalev SEPP

IPC分类号： H03L7/00

CPC分类号： G01R31/31709

摘要： Timebase variation compensation in a measurement instrument is achieved by simultaneously acquiring both a signal under test and a reference signal. The reference signal is derived from a source that has very stable timing with respect to the timebase. Timing variations are measured from the acquired signals. Timing variations detected in the reference signal are deemed to reflect variations in the timebase of the test and measurement instrument. The timing variations in the reference signal are used to detect, and compensate for, timebase variation in the signal under test to produce a corrected signal under test that reflects the actual timing variations present in the signal under test.

摘要翻译： 测量仪器中的时基变化补偿通过同时获取被测信号和参考信号来实现。 参考信号源自相对于时基具有非常稳定的定时的源。 从所获取的信号测量时序变化。 在参考信号中检测到的定时变化被认为反映了测试和测量仪器的时基的变化。 参考信号的定时变化用于检测和补偿被测信号中的时基变化，以产生反映被测信号中存在的实际定时变化的被测信号。