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:
Nov. 02, 1993
Filed:
Apr. 16, 1992
Northern Telecom Limited, Montreal, CA;
Abstract
An impedance generator, especially suitable for determining a terminating impedance of an active impedance telephone line interface circuit, comprises a subtracting circuit for forming a difference between an input voltage multiplied by a multiplier and a high pass filtered version of the difference multiplied by another multiplier, and a summing circuit for combining the input voltage multiplied by a further multiplier with a low pass filtered version of said difference to produce an output voltage. In one arrangement, the input voltage multiplied by the further multiplier constitutes a third input to the subtracting circuit. The high pass filtered version of the difference is produced by subtracting the output of a low pass filter from the difference. The multipliers are constituted by controllable gain elements, enabling the generated impedance to be easily programmed under digital control.