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:
May. 08, 2001
Filed:
Apr. 05, 1999
Applicant:
Inventors:
Joseph M. Cannon, Harleysville, PA (US);
James A. Johanson, Macungie, PA (US);
Paul J. Davis, Wayne, PA (US);
Assignee:
Agere Systems Guardian Corp., Miami Lakes, FL (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04M 3/00 ;
U.S. Cl.
CPC ...
H04M 3/00 ;
Abstract
Apparatus and methods for adaptively, reliably, and accurately measuring the frequency of an alerting or other signaling tone. A tone detector measures the frequency of a tone (continuous or pulsed) with a high degree of accuracy (e.g., to within 1 part in 10,000). Two lower order or smaller DFTs measure the energy level in two separate but intersecting frequency ranges. A simple ratio is determined from the relative energy measured from discrete Fourier transforms relating to each of the two separate frequency ranges, and an actual measured frequency is determined.