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    2.
    发明专利
    未知

    公开(公告)号：DE69909292T2

    公开(公告)日：2004-04-22

    申请号：DE69909292

    申请日：1999-10-13

    Applicant: ST MICROELECTRONICS NV ,  ST MICROELECTRONICS SA

    Inventor： ISAKSSON MIKAEL ,  MESTDAGH DENIS JULIEN GILLES ,  OLSSON LENNART

    IPC: H04J11/00 ,  H04B3/32 ,  H04L5/02 ,  H04L7/00 ,  H04L27/26 ,  H04M1/74

    Abstract: In a DMT telecommunciations transmission system having at least two VDSL systems, each comprising a pair of modems, and belonging to a single binder group common to both VDSL systems, a method is described for keeping DMT frames aligned to the same frame timing. In this way, orthogonality holds and adjacent carriers can be used for different transmission directions without an capacity loss due to NEXT cross-talk. The steps are: estimating the time mis-alignment and power of cross-talk DMT signals added to a received DMT signal. The estimate is used by the modem to synchronise its own frame timing to a main cross-talker's frame timing auto-correlation is used on the received signal and a delayed copy of the received signal correlation maxima determine the frame boundaries of different DMT components of the received signal.

    3.
    发明专利
    未知

    公开(公告)号：DE69909292D1

    公开(公告)日：2003-08-07

    申请号：DE69909292

    申请日：1999-10-13

    Applicant: ST MICROELECTRONICS NV ,  ST MICROELECTRONICS SA

    Inventor： ISAKSSON MIKAEL ,  MESTDAGH DENIS JULIEN GILLES ,  OLSSON LENNART

    IPC: H04J11/00 ,  H04B3/32 ,  H04L5/02 ,  H04L7/00 ,  H04L27/26 ,  H04M1/74

    Abstract: In a DMT telecommunciations transmission system having at least two VDSL systems, each comprising a pair of modems, and belonging to a single binder group common to both VDSL systems, a method is described for keeping DMT frames aligned to the same frame timing. In this way, orthogonality holds and adjacent carriers can be used for different transmission directions without an capacity loss due to NEXT cross-talk. The steps are: estimating the time mis-alignment and power of cross-talk DMT signals added to a received DMT signal. The estimate is used by the modem to synchronise its own frame timing to a main cross-talker's frame timing auto-correlation is used on the received signal and a delayed copy of the received signal correlation maxima determine the frame boundaries of different DMT components of the received signal.

    5.
    发明专利
    未知

    公开(公告)号：DE69922176T2

    公开(公告)日：2005-11-10

    申请号：DE69922176

    申请日：1999-02-17

    Applicant: ST MICROELECTRONICS NV

    Inventor： ISAKSSON MIKAEL ,  BENGTSSON DANIEL ,  SJOEBERG FRANK ,  OEDLING PER ,  NILSSON RICKARD ,  BAHLENBERG GUNNAR ,  JOHANSSON MAGNUS ,  OLSSON LENNART ,  OEKVIST GOERAN

    IPC: H04L5/14 ,  H04L27/26 ,  H04L5/06

    Abstract: Zipper is the time-synchronized frequency-division duplex implementation of discrete multi-tome (DMT) modulation. Two communicating Zipper modems transmit DMT symbols simultaneously with a common clock. When all transmitters are time synchronized, the near end cross-talk (NEXT) and near end echoes injected into the received signal are orthogonal to the desired signal. The present invention provides a telecommunications transmission system using zipper and having at least two VDSL systems. Each VDSL system comprises a pair of zipper modems communicating over a cable transmission path. The telecommunications transmission system handles zipper transmission transmitted over the common cable; at least partly mitigates NEXT; and permits transmissions in a first VDSL system which are asynchronous with transmissions in a second VDSL system.

    6.
    发明专利
    未知

    公开(公告)号：DE69905040T2

    公开(公告)日：2004-01-22

    申请号：DE69905040

    申请日：1999-05-11

    Applicant: ST MICROELECTRONICS NV

    Inventor： JOHANSSON MAGNUS ,  OLSSON LENNART ,  BAHLENBERG GUNNAR ,  BENGTSSON DANIEL ,  ISAKSSON MIKAEL ,  OLOFSSON SVEN-RUNE ,  OEKVIST GOERAN

    IPC: H04L25/03 ,  H04L27/26 ,  H04L5/06

    Abstract: In a multi-carrier system employing OFDM, for example DMT, an adaptive channel equalizer is normally used, operating in the frequency domain. The sampling clock is controlled so that the time delay between the transmitter and the receiver is effectively eliminated. If the information used to control the sampling clock is received from the equalized data stream, it will introduce an ambiguity between the operation of the channel equalizer and the mechanism used to control the sampling clock. Operation of the equalizer can mask an increasing time difference, between transmitter and receiver, which the sample clock controller should be tracking. The present invention eliminates the ambiguities in the operation of the equalizer and sample clock controller by preventing the equalizer accepting time differences which should be corrected by operation of the sample clock controller.

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