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:
Jul. 12, 1994
Filed:
Nov. 30, 1992
Applicant:
Inventors:
Assignee:
Motorola, Inc., Schaumburg, IL (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04M / ; H04M / ;
U.S. Cl.
CPC ...
379399 ; 379403 ; 379404 ; 379413 ;
Abstract
A subscriber line interface circuit (SLIC) sets AC and DC output impedances as seen by first and second transmission signals. The common mode variation and differential variation of the first and second transmission signals is AC-sensed to provide a common mode feedback signal and a differential feedback signal which in turn controls the AC output impedance. The DC component of the first and second transmission signals is blocked allowing downstream amplifiers to operate at reduced power supply potentials. The DC variation of the first and second transmission signals is also sensed for providing a DC feedback signal to control the DC output impedance.