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. 23, 2003
Filed:
Aug. 24, 1999
Paul D. Hendricks, Coopersburg, PA (US);
Donald R. Laturell, Allentown, PA (US);
Lane A. Smith, Easton, PA (US);
Steven B. Witmer, Spring Township, Berks County, PA (US);
Agere Systems Guardian Corp., Allentown, PA (US);
Abstract
An AC impedance matching architecture which provides programmable AC impedance matching in a given range using a digital filter to filter a signal fed back from the impedance matched line to generate an AC impedance emulation control signal. The AC impedance emulation control signal is combined with a transmit signal (if desired) and drives a voltage controlled current source, which is in parallel with a reference impedance. A voltage is developed across the reference impedance to drive, e.g., the telephone line. The reference impedance is chosen based on a desired maximum AC impedance. The gain of the digital filter, a first order sigma delta filter in the disclosed embodiment, is chosen based on the desired value of the AC impedance. The transfer function of the digital filter is derived based on a desired AC impedance.