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:
Aug. 04, 1992
Filed:
Aug. 05, 1991
Shawn McCaslin, Cedar Creek, TX (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A method of detecting a wideband tone, having a nominal frequency but occurring anywhere within a wide range of frequencies, includes a step of bandpass filtering input data. The bandpass-filtered data is used to predict a value of the input data using an algorithm such as least-mean-squares (LMS) adaptive linear prediction. An error signal is provided as a difference between the actual and predicted values of the input data. By computing the power in the error signal, the presence or absence of a tone can be detected, because a tone causes a smaller prediction error and power than other, non-tone processes such as white noise. A high-to-low transition in power represents a start of a tone, whereas a low-to-high transition in power represents an end of a tone. A tone flag signal is provided in response to a predetermined relationship between two power computations, such as a low-to-high transition.