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公开(公告)号：EP0766412A3
公开(公告)日：1998-12-09
申请号：EP96307072
申请日：1996-09-27
申请人： PARADYNE CORP
CPC分类号： H04B3/238
摘要： A far-end modem (300) transmits a "pilot tone" during the time that a near-end modem (100) is training its echo canceller (650). Correspondingly, the near-end modem (100) is modified to notch or filter out this pilot tone from the received signal. The filtered received signal is then used by the near-end modem (100) to train its echo canceller (650).
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2.发明公开FILTER SYSTEM AND METHOD TO SUPPRESS INTERFERENCE IMPOSED UPON A FREQUENCY-DIVISION MULTIPLEXED CHANNEL 审中-公开过滤系统和方法要解决的问题实行了频率，声道减少
公开(公告)号：EP1325605A4
公开(公告)日：2005-06-22
申请号：EP00957358
申请日：2000-08-10
申请人： PARADYNE CORP
发明人： BINGEL THOMAS J , BREMER GORDEN , HAZEN RAMON B
CPC分类号： H04M1/738 , H04M11/062
摘要： A filter system and method is disclosed, the filter system (300, 300x, 300y, 300z) being connected between a large-amplitude, high-frequency noise source (304) and a frequency-division multiplexed communications channel (312, 412). The large-amplitude, high-frequency noise (413) commonly being a plain old telephone service (POTS) ring signal generated by a central office (CO) telephone switch (404). The frequency-division multiplexed communications channel (312, 412) generally used to carry digital signals at frequencies above the POTS baseband in order to implement a digital subscriber line (DSL). Large-amplitude, high-frequency signal components (413) from the POTS ring signal impair the performance of frequency-division multiplexed channels (312, 412) on a transmission line such as a subscriber loop (512, 613). The filter system (300, 300x, 300y, 300z) of the present invention utilizes amplitude and also may utilize frequency to selectively suppress the transients and harmonics on the transmission line caused by a telephone ring signal. In addition, the present invention uses bi-directional current limiting filters (700, 800) to implement some of the amplitude-dependent filtering behavior.
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公开(公告)号：EP0766411A3
公开(公告)日：1998-12-09
申请号：EP96307071
申请日：1996-09-27
申请人： PARADYNE CORP
摘要： A processor (650) of a cellular modem (100) monitors for the presence of a residual echo signal during a full-duplex portion of a training sequence. In particular, the processor (650) monitors an equalizer error signal during a full-duplex training phase that follows the half-duplex training phase for the echo canceller. If the processor (650) detects a level of the error signal greater than a predefined threshold, it presumes the increase in the error signal is due to the presence of a residual echo signal and performs a predefined adjustment of the echo filter taps of the corresponding echo canceller of the cellular modem (100).
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公开(公告)号：EP0766413A3
公开(公告)日：1998-12-16
申请号：EP96307073
申请日：1996-09-27
申请人： PARADYNE CORP
CPC分类号： H04B3/23
摘要： A fast response gain tracker (610) operates to adjust the magnitude of an echo cancellation signal developed from an echo canceler. The fast response gain tracker (610) provides an adjusted echo cancellation signal that is subtracted from an echo-corrupted received signal to provide an echo-canceled signal. In particular, the fast response gain tracker (610) correlates the echo-canceled signal with the echo cancellation signal from the echo canceler. If the gain of the gain tracker is correct the echo is canceled and there is zero correlation between the echo-canceled signal and the echo cancellation signal. However, if the echo level changes then a residual echo component appears in the echo-canceled signal, which now becomes correlated with the echo cancellation signal. In response, the magnitude of the gain tracker automatically adjusts the gain of the echo cancellation signal to match the change in echo level and thereby subsequently eliminates the residual echo.
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