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:
Apr. 08, 1997
Filed:
Jun. 07, 1995
Stephen G Dame, Everett, WA (US);
Virtual DSP Corporation, Everett, WA (US);
Abstract
A method and device for very quickly and accurately determining the fundamental frequency of an input analog electrical signal. The method first uses sparse range autocorrelation to determine the note which is closest to the fundamental frequency. It then uses fine range autocorrelation and interpolation to calculate more precisely the exact pitch. Smoothing is employed for both the sparse range determination and the subsequent fine range determination to reject spurious signals. Because the sparse autocorrelation produces good results with merely one or two full cycles of the fundamental frequency, the initial sparse determination can be made in less than ten milliseconds and this is updated with a fine determination less than two milliseconds later.