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    FAR-END ECHO CANCELER
    81.
    发明专利
    FAR-END ECHO CANCELER 失效

    公开(公告)号：JPH05206899A

    公开(公告)日：1993-08-13

    申请号：JP22457892

    申请日：1992-08-03

    Applicant: SGS THOMSON MICROELECTRONICS

    Inventor： DOMINIKU BIKAARU ,  UIRIAMU GURASU ,  FURANSHISU DEYURUURI

    IPC: H04B1/58 ,  H04B3/23

    Abstract: PURPOSE: To provide a far-end echo canceler which does not require any special external memory and can prevent the increase of the chip size of a data pump circuit. CONSTITUTION: A far-end echo canceler for a duplex modem is provided at least with one data pump type high-speed processor 30 for filtering operation and a microcontroller 41 for control which is required for canceling far-end echoes. The data required for canceling the far-end echoes correspondingly to transmitted data are coupled with the microcontroller 41 and stored in a memory 43 which is controlled by the microcontroller 41.

    SUBSCRIBER CIRCUIT
    82.
    发明专利
    SUBSCRIBER CIRCUIT 失效

    公开(公告)号：JPH04280597A

    公开(公告)日：1992-10-06

    申请号：JP4314291

    申请日：1991-03-08

    Applicant: NEC CORP

    Inventor： ARAI MASANOBU ,  HIRAOKA TOSHIHIDE

    IPC: H04B3/23 ,  H04B1/58 ,  H04M3/00 ,  H04M19/00 ,  H04Q3/42 ,  H04Q11/04

    Abstract: PURPOSE:To use a subscriber circuit for analog telephone set in common use with a subscriber circuit implementing duplex transmission of a digital signal by the echo canceller system. CONSTITUTION:An analog circuit 1 generates a signal to be sent to a 2-wire subscriber line, receives a signal reached from the 2-wire subscriber line and revises a termination impedance by external control. An A/D converter 2 converts a signal received by the analog circuit 1 into a digital signal. A digital circuit 3 implements digital signal processing by the control of the firmware and selects calculation of balance network or calculation of CODEC filter and echo canceller calculation or equalizing discrimination calculation by external control. Since the selection is attained by external control through the revision of a software data, the revision of the service is very simply implemented and work installation cost is reduced.

    HYBRID CIRCUIT
    83.
    发明专利
    HYBRID CIRCUIT 失效

    公开(公告)号：JPH0468809A

    公开(公告)日：1992-03-04

    申请号：JP17733990

    申请日：1990-07-06

    Applicant: FUJITSU LTD

    Inventor： TSUNOISHI MITSUO

    IPC: H03H21/00 ,  H03H17/00 ,  H03H17/02 ,  H04B1/58 ,  H04B3/23

    Abstract: PURPOSE:To enable econimization by setting the element value of a source equivalent circuit corresponding to the constitution of a two-line/four-line conversion part, calculating a filter coefficient by converting the source equivalent circuit to a specified impedance function, and deriving a cancel signal by a digital filter using the obtained filter coefficient. CONSTITUTION:The element value of the source equivalent circuit is set by an element value set part 26 and converted to the impedance function of a (z) function by the bilinear conversion of an over sampling frequency at an impedance function calculation part 25. Coefficient calculation parts 21 and 22 calculate the and a digital balancing circuit arithmetic part 19 calculate the filter coefficient by substituting this impedance function to a transmission function. On the other hand, transmission coarse gain set information and reception coarse gain set information for controlling the gains of coarse gain control circuits 12 and 13 is applied to a plane gain calculation part 18 and according to the coarse gain control of the coarse gain circuits 12 and 13, level control is executed to cancel a crosstalk component. Thus, economization is enabled.

    84.
    实用新型
    失效

    公开(公告)号：JPH02103941U

    公开(公告)日：1990-08-17

    申请号：JP1331989

    申请日：1989-02-07

    IPC: H04B1/58 ,  H04B3/03 ,  H04B3/20

    90.
    发明专利
    失效

    公开(公告)号：JPS62501117A

    公开(公告)日：1987-04-30

    申请号：JP50003285

    申请日：1985-11-22

    IPC: H04B1/58 ,  H04L12/413

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