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:
Jun. 09, 1998
Filed:
Jan. 15, 1997
Jeffrey Wayne Daugherty, Lisle, IL (US);
Richard Harry Ketchum, Wheaton, IL (US);
Lucent Technologies Inc., Murray Hill, NJ (US);
Abstract
A first validation circuit utilizes residual energy unaccounted for by a linear predictive coding model for a specified order of model as a criteria on which to make a validity determination of whether a valid tone or digit has been received. A second validation circuit operating in conjunction with the first validation circuit utilizes discrete Fourier transforms at the center and adjacent frequencies to energy peaks associated with tones. A ratio of the peak energy to the adjacent energies is utilized in combination with corresponding thresholds to make a validity determination. The combination of the first and second validation circuit provides a high level of confidence that a particular tone or digit has been detected.