EP 1325605 A1 20030709 - FILTER SYSTEM AND METHOD TO SUPPRESS INTERFERENCE IMPOSED UPON A FREQUENCY-DIVISION MULTIPLEXED CHANNEL
Title (en)
FILTER SYSTEM AND METHOD TO SUPPRESS INTERFERENCE IMPOSED UPON A FREQUENCY-DIVISION MULTIPLEXED CHANNEL
Title (de)
FILTERSYSTEM UND VERFAHREN ZUR UNTERDRÜCKUNG VON STÖRUNGEN, DIE EINEM FREQUENZGEMULTIPLEXTEN KANAL AUFERLEGT WERDEN
Title (fr)
SYSTEME DE FILTRAGE ET PROCEDE CORRESPONDANT PERMETTANT DE SUPPRIMER UN BROUILLAGE SUR UN CANAL MULTIPLEXE PAR REPARTITION EN FREQUENCE
Publication
Application
Priority
US 0021820 W 20000810
Abstract (en)
[origin: WO0215539A1] 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.
IPC 1-7
IPC 8 full level
H02H 9/02 (2006.01); H04M 1/738 (2006.01); H04M 1/76 (2006.01); H04M 11/06 (2006.01)
CPC (source: EP)
H04M 1/738 (2013.01); H04M 11/062 (2013.01)
Designated contracting state (EPC)
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
DOCDB simple family (publication)
WO 0215539 A1 20020221; AU 6899100 A 20020225; EP 1325605 A1 20030709; EP 1325605 A4 20050622
DOCDB simple family (application)
US 0021820 W 20000810; AU 6899100 A 20000810; EP 00957358 A 20000810