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.:

US 9179202 B1

PDF
Full Text
Expired
Date of Patent:
Nov. 03, 2015

Filed:

Sep. 16, 2013
Applicant:

The United States of America, As Represented BY the Secretary of the Army, Washington, DC (US);

Inventor:

Wei Su, Bel Air, MD (US);

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04Q 1/45 (2006.01);
U.S. Cl.
CPC ...
H04Q 1/45 (2013.01);
Abstract

A multi-frequency (also known as multiple-frequency) signal, such as a dual-tone signal, can be a repeating signal that indicates a character designated on a keypad. The signal can be processed such that the character is identifiable. This processing can include using first and second-order statistics of the signal to determine an estimated average frequency of the signal. A table can be accessed that lists individual characters of the keypad and specific average frequency values can be associated with the individual characters. The specific average frequency value that is closest to the estimated average frequency can be identified and the character associated with this closest specific average frequency value can be appointed as the character indicated by the signal. Thus, the multi-frequency signal can be classified as communicating the appointed character.


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