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:
Aug. 19, 1986
Filed:
Jul. 27, 1984
Philip T Martin, Raleigh, NC (US);
ITT Corporation, New York, NY (US);
Abstract
In a transformer-coupled interface circuit for interconnecting two-wire and four-wire telephone communication channels, there are provided a bucking winding in the transformer and a flux compensation circuit which drives the bucking winding. The flux compensation circuit includes a sensor of direct current current flowing through a primary winding of the transformer for applying power to a subscriber telephone. Also included within the compensation circuit is a current source responsive to the measured primary current for controlling the magnitude of the bucking winding current to track the primary current, thereby to reduce the flux in the transformer core and permit use of a smaller sized core. A stabilization circuit within the current source prevents oscillation resulting from feedback and reactive circuit components.