公开(公告)号：US5901289A

公开(公告)日：1999-05-04

申请号：US838842

申请日：1997-04-11

申请人： Mark A. Leonard ,  Trevor S. R. Dyck ,  Peter Wai-Wah Ma

发明人： Mark A. Leonard ,  Trevor S. R. Dyck ,  Peter Wai-Wah Ma

IPC分类号： G06T9/00 ,  H04N7/26 ,  H04N17/00 ,  H04N21/431 ,  H04N21/434 ,  H04N21/443 ,  H04N21/47 ,  G06F13/00

CPC分类号： H04N17/004 ,  H04N19/00 ,  H04N21/431 ,  H04N21/4316 ,  H04N21/4345 ,  H04N21/4438 ,  H04N21/47

摘要： A system and method for displaying MPEG-2 packets as a hierarchy of tables within a window of a graphical display. This hierarchial display is updated continuously as new packets are received, thus providing a real time display. When a packet is received, and the location of that packet has not been identified, the packet is placed at the top of the hierarchy. Once a subsequent packet is received wherein the subsequent packet identifies the location of the earlier received packet, the earlier received packet is moved to its correct location within the hierarchy. When a user of the system clicks one of the tables within the hierarchy, the system saves the next data packet or packets containing data for the table into a display table buffer. The system then displays a second window and formats the data from the display table buffer into the second window.

摘要翻译： 一种用于在图形显示的窗口内将MPEG-2数据包显示为表的层次结构的系统和方法。 当接收到新的分组时，该分层显示被连续更新，从而提供实时显示。 当接收到分组，并且该分组的位置尚未被识别时，分组被放置在层次结构的顶部。 一旦接收到后续分组，其中随后的分组标识较早接收的分组的位置，则较早接收的分组被移动到其等级内的正确位置。 当系统的用户点击层次结构中的一个表时，系统将下一个数据包或包含表的数据的数据包保存到显示表缓冲区中。 然后，系统显示第二个窗口，并将数据从显示表缓冲区格式化为第二个窗口。

公开(公告)号：US5883924A

公开(公告)日：1999-03-16

申请号：US878423

申请日：1997-06-18

申请人： Michael Yiu-Kwan Siu ,  Trevor S. R. Dyck ,  Simon Alexander Block ,  Chong T Ong

发明人： Michael Yiu-Kwan Siu ,  Trevor S. R. Dyck ,  Simon Alexander Block ,  Chong T Ong

IPC分类号： H04L29/14 ,  H04N17/00 ,  H03B3/46

CPC分类号： H04N17/004

摘要： A method and a test instrument are provided for measuring program clock reference (PCR) jitter in a data stream, such as an MPEG-2 transport stream. The test instrument includes a line interface circuit for receiving the data stream, a digital computer for processing the data stream and a local clock for generating timestamps. The digital computer extracts from the data stream a PCR sample value which represents a count of a system time clock used to generate the data stream. The timestamp is obtained from the local clock and is associated with the PCR sample value. The digital computer determines a reconstructed system time clock from a set of values including the PCR sample value and the timestamp, and previously-received PCR sample values and associated timestamps within a window representative of a predetermined time interval. The window is shifted as new PCR sample values are received. The digital computer determines a PCR jitter value for the PCR sample value by determining a deviation of the PCR sample value from the reconstructed system time clock. The PCR jitter value may be displayed on a display unit, preferably in a histogram.

摘要翻译： 提供了一种用于测量诸如MPEG-2传输流之类的数据流中的程序时钟参考（PCR）抖动的方法和测试仪器。 测试仪器包括用于接收数据流的线路接口电路，用于处理数据流的数字计算机和用于产生时间戳的本地时钟。 数字计算机从数据流中提取表示用于生成数据流的系统时钟的计数的PCR样本值。 时间戳从本地时钟获得，并与PCR样本值相关联。 数字计算机从代表预定时间间隔的窗口中的一组值确定重构的系统时钟，以及先前接收到的PCR样本值和相关联的时间戳。 当接收到新的PCR样本值时，窗口移动。 数字计算机通过确定PCR样本值与重构的系统时钟的偏差来确定PCR样本值的PCR抖动值。 PCR抖动值可以显示在显示单元上，优选地在直方图中显示。

公开(公告)号：US5774497A

公开(公告)日：1998-06-30

申请号：US632036

申请日：1996-04-12

申请人： Simon A. Block ,  Trevor S. R. Dyck

发明人： Simon A. Block ,  Trevor S. R. Dyck

IPC分类号： H04L29/14 ,  H04N17/00 ,  H03B3/46

CPC分类号： H04N17/004

摘要： A method and a test instrument are provided for measuring program clock reference (PCR) jitter in a data stream, such as an MPEG-2 transport stream. The test instrument includes a line interface circuit for receiving the data stream, a digital computer for processing the data stream, a local clock for generating timestamps and a display unit. The digital computer extracts from the data stream a PCR sample which represents a count of a system time clock used to generate the data stream. The timestamp is obtained from the local clock and is associated with the PCR sample value. The digital computer determines a line of best fit to a set of values including the PCR sample value and the timestamp, and previously received PCR sample values and associated timestamps. The line of best fit represents a reconstructed system time clock. The digital computer determines a PCR jitter value for the PCR sample value by determining a distance between the line of best fit and the PCR sample value. The PCR jitter value may be displayed on the display unit, preferably in a histogram.

摘要翻译： 提供了一种用于测量诸如MPEG-2传输流之类的数据流中的程序时钟参考（PCR）抖动的方法和测试仪器。 测试仪器包括用于接收数据流的线路接口电路，用于处理数据流的数字计算机，用于产生时间戳的本地时钟和显示单元。 数字计算机从数据流中提取表示用于生成数据流的系统时钟的计数的PCR样本。 时间戳从本地时钟获得，并与PCR样本值相关联。 数字计算机确定与包括PCR样本值和时间戳以及先前接收的PCR样本值和相关联的时间戳的一组值最佳拟合的线。 最佳拟合线表示重构的系统时钟。 数字计算机通过确定最佳拟合线与PCR样本值之间的距离来确定PCR样本值的PCR抖动值。 PCR抖动值可以显示在显示单元上，优选地以直方图显示。