Patent ID: 6188750
Filing Date: 2001-02-13
Classification: H04M

Abstract:
An impedance blocking filter circuit used in telecommunication systems for interconnecting between incoming telephone lines and customer's terminal equipment so as to unconditionally block impedances from above 20 KHz due to the customer's terminal equipment from an ADSL network unit and/or home networking interface unit, said filter circuit comprising:first, second, and third inductors connected in series between a first input terminal and a first common point;said first inductor having its one end connected to said first input terminal and its other end connected to one end of said second inductor, said second inductor having its other end connected to one end of said third inductor, said third inductor having its other end connected to said first common point;a first resistor having its one end also connected to said first common point and its other end connected to a first output terminal;fourth, fifth, and sixth inductors connected in series between a second input terminal and a second common point;said four inductor having its one end connected to said second input terminal and its other end connected to one end of said fifth inductor, said fifth inductor having its other end connected to one end of said sixth inductor, said sixth inductor having its other end connected to said second common point;a second resistor having its one end also connected to said second common point and its other end connected to a second output terminal; anda capacitor having its one end connected to said first common point and its other end connected to said second common point.