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:
Feb. 06, 1990
Filed:
Oct. 30, 1987
Jean Appel, Vanves, FR;
Office National d'Etudes et de Recherche Aerospatiales, Chatillon, FR;
Abstract
The occurrence and frequency of a periodic component embedded in a composite waveform including noise is detected by real time calculating the autocorrelation function of the waveform and deducing the frequency of the periodic component from the value of the autocorrelation function coefficients. An analog-to-digital converter periodically transforms the waveform into samples having q bits. The samples are delayed by a predetermined time interval .DELTA.t and multiples thereof, to derive 2n delayed samples, x.sub.i, x.sub.i-1 . . . x.sub.i-2n. The delayed samples are multipled to derive 2n products, such that the first n products are represented by x.sub.1 .multidot.x.sub.i-k and the second n products are represented by x.sub.1-n .multidot.x.sub.i-(n+k), where k is selectively 1 . . . n. Difference between the first and second products are obtained as (P.sub.1 -P.sub.n+1) . . . (P.sub.n-1 -P.sub.2n), where P.sub.1 =x.sub.i .multidot.x.sub.i-1, P.sub.n-1 =x.sub.i .multidot.x.sub.i-n, P.sub.+1 =x.sub.i-n .multidot.x.sub.i- n+1, P.sub.2n =x.sub.i-n .multidot.x.sub.i-2n. The differences are integrated to derive autocorrelation funtion coefficients of the input signal. In response to at least one of the coefficients exceeding a predetermined threshold, an indication that the input signal contains a periodic component is derived.