U.S. Philips Corporation

Willem-Arie Sloof

Wolfdietrich G Kasperkovitz

Wolter Bijker

Hendricus C De Ruytere

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.

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Eindhoven, Netherlands

Willem-Arie Sloof