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. 30, 2005
Filed:
May. 07, 2002
Burkhard Dick, Hamburg, DE;
Burkhard Dick, Hamburg, DE;
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
The invention relates to an anti-demodulator circuit which is fundamentally built up in the same way as a demodulator circuit but, instead of a bandpass filter as generally used in a demodulator, comprises a notch filter which receives an input signal comprising a useful signal and an interference signal, and generates a filtered signal. The notch filter has a center frequency which approximately corresponds to the frequency of the input signal so as to suppress at least a part of the useful signal. The anti-demodulator circuit further comprises a mixer circuit which receives the filtered signal and a phase-shifted input signal and supplies a demodulated output signal which substantially corresponds to the interference signal. The invention can be particularly used in connection with a filtering device for suppressing interference signals based on adjacent channel disturbances in FM radios, in which the bandwidth of the filtering device is controlled in dependence upon the output signal of the anti-demodulator circuit.