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:
Oct. 15, 1985
Filed:
Jul. 29, 1983
John J Gibson, Princeton, NJ (US);
RCA Corporation, Princeton, NJ (US);
Abstract
An FM signal is demodulated by the technique of sequentially sampling the signal and combining the samples to approximate the standard formula for the instantaneous frequency deviation ##EQU1## where the dots indicate the first derivative of the samples. The FM signal is assynchronously sampled at approximately four times the carrier frequency rate. Alternate samples are substantially equivalent to orthogonal components x and y of the FM signal. At least four successive samples are successsively stored so that at least four of the lastmost samples are always available for processing. Particular x samples are summed to create averaged samples x.sub.n and differenced to create approximations of derivatives x.sub.n of the x signal components and particular y samples are similarly summed and differenced to create averaged values y.sub.n and derivatives y.sub.n. These values are used in the equation for F.sub.n. In terms of successive samples, S, the equation for F.sub.n becomes