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. 23, 1994
Filed:
Apr. 14, 1993
Wolter Bijker, Eindhoven, NL;
Wolfdietrich G Kasperkovitz, Eindhoven, NL;
Hendricus C De Ruytere, Eindhoven, NL;
Willem-Arie Sloof, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
FM quadrature demodulator having in-phase and quadrature terminals for applying a pair of FM-modulated signals in a mutual phase quadrature thereto, having a modulation signal which is frequency-modulated on a carrier, one of the two terminals being coupled to a first input of a first phase comparison circuit and the other terminal being coupled to a second input of the first phase comparison circuit via a first phase-shifting circuit which realizes a phase shift varying with said modulation signal, the first phase comparison circuit being connected to an output of the FM quadrature demodulator via a low-pass filter. In order to enhance, inter alia, the signal processing and the field of use of the FM quadrature demodulator, this demodulator includes a second phase comparison circuit having first and second inputs, in which one of the two in-phase and quadrature terminals is coupled to the first input of the second phase comparison circuit and the other terminal is coupled to the second input of the second phase comparison circuit via a second phase-shifting circuit which realizes a phase shift varying with the modulation signal, the FM quadrature demodulator also having a differential stage which is coupled between outputs of the two phase comparison circuits and an input of the low-pass filter.