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. 22, 1989
Filed:
Oct. 07, 1988
Walter Braun, Wettingen, CH;
BBC Brown Boveri AG, Baden, CH;
Abstract
A method for demodulating an FM signal (FM=Frequency Modulation), in which the FM signal is directly mixed down into an in-phase and a quadrature component of a complex frequency baseband and a modulation signal is determined from a phase relationship of the complex frequency baseband signal, and the phase relationship is determined from a curve length of the frequency baseband signal. The curve length is approximated by a length of a polygon curve which is spanned by successive sampled values of the complex frequency baseband signal. An estimated radius of an envelope curve of the complex frequency baseband is preferably used for normalizing the curve length. A signal receiver according to the invention comprises a direct converter (2), AC-coupled amplifiers (5a, 5b), a demodulator (6a) and a loudspeaker (8).