The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 12, 1989
Filed:
Aug. 16, 1988
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
The subscriber line interface circuit comprises subscriber nodes, reception nodes and transmission nodes, a power feeding unit, adders, impedance elements, an inverting amplifier, and a feedback element. The subscriber nodes are coupled to a subscriber terminal via a subscriber line, and the reception and transmission nodes are coupled to an exchange via a reception line and a transmission line, respectively. The feeding unit supplied a DC current to the terminal and controls the current. The first adder adds the voltage between the subscriber nodes and the voltage from the reception node. The first impedance element has an impedance corresponding to a real-number multiplication of the impedance between the subscriber nodes, and is applied with the output voltage of the first adder. The amplifier is given with the output of the first impedance element. The second impedance element, inserted in the feedback path of the amplifier, has an impedance corresponding to a real-number multiplication of the impedances of the subscriber line and the terminal. The feedback element supplies, to the feeding unit, a signal corresponding to the current flowing through the first impedance element as a control signal. The second adder adds the output voltage of the amplifier, the output voltage of the first adder and the voltage of the reception nodes, and supplies the resultant signal to the transmission nodes.