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:
Dec. 28, 1993
Filed:
Oct. 29, 1990
Gyula Jakab, Nepean, CA;
Northern Telecom Limited, Montreal, CA;
Abstract
A telephone line interface circuit includes a transformer provided with first, second and third windings. The first winding is connected across the tip and ring wires of the telephone line and the second winding is connected to the output of an amplifier which has an input connected to a receive line. In a first case where the input to which the receive line is connected is the inverting input, a first resistor is connected in series between the receive line and the inverting input. The third winding is connected in series with a second resistor to form a feedback loop which is connected to the inverting input of the amplifier. The transfer function of the interface circuit is dependent on the ratio of the resistances of the first and second resistors and the turns ratio of the first winding to the third winding but is substantially independent of transformer parasitics. In the case where the receive line is connected to the non-inverting input, the first and second resistors are not required and the transfer function is dependent only on the turns ratio.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile