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    DSL TRANSMISSION SYSTEM FOR COMPENSATING FAR-EDGE CROSSTALK
    1.
    发明专利
    DSL TRANSMISSION SYSTEM FOR COMPENSATING FAR-EDGE CROSSTALK 失效

    公开(公告)号：JP2001237747A

    公开(公告)日：2001-08-31

    申请号：JP2000377457

    申请日：2000-12-12

    Applicant: ST MICROELECTRONICS SA ,  ST MICROELECTRONICS NV

    Inventor： NORDSTROEM TOMAS ,  BENGTSSON DANIEL ,  ISSON OLIVIER

    IPC: H04J11/00 ,  H04B1/62 ,  H04B3/32 ,  H04L25/03 ,  H04L27/26

    Abstract: PROBLEM TO BE SOLVED: To provide a canceller circuit which can eliminate far-edge crosstalks, in a digital subscriber circuit transmission system. SOLUTION: This system includes a pre-compensation means which multiplies a vector S=(Si), where i is equal to 1 to n by a pre-compensation matrix M prior to transmission, so as to obtain a diagonal matrix product H*M. In this example, H is a transmission matrix of plural transmission channels as prescribed by R=H*S and R=(Ri), where i is equal to 1 to n is a vector of discrete multi-tone symbol Ri that is received by a modem. Such a system configuration is attained by a far-edge crosstalk eliminating circuit.

    3.
    发明专利
    未知

    公开(公告)号：DE69915082D1

    公开(公告)日：2004-04-01

    申请号：DE69915082

    申请日：1999-12-14

    Applicant: ST MICROELECTRONICS NV ,  ST MICROELECTRONICS SA

    Inventor： NORDSTROEM THOMAS ,  BENGTSSON DANIEL ,  ISSON OLIVIER

    IPC: H04J11/00 ,  H04B1/62 ,  H04B3/32 ,  H04L25/03 ,  H04L27/26

    Abstract: The invention relates to a far-end crosstalk (FEXT) canceling circuit for a digital subscriber line transmission system, said transmission system comprising a plurality n of line termination (LT) modems (Mi) transmitting discrete multitone (DMT) symbols Si to corresponding network (NT) termination modems (Mc(i)) over n transmission channels. The invention proposes to multiply the vector S = (Si) i = 1 to n, before transmission, by a precompensation matrix M such that the matrix product H*M is diagonal, H being the transfer matrix of the n downstream transmission channels defined by R = H*S where R = (Ri), i = 1 to n, is the vector of the DMT symbols Ri respectively received by the modems Mc(i).

    6.
    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.

    7.
    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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