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:
May. 24, 1977
Filed:
Jan. 14, 1976
John M Ferrara, Hardley, PA (US);
Frank Patterson Smith, 2nd, Dresher, PA (US);
Narco Scientific Industries, Inc., Fort Washington, PA (US);
Abstract
A circuit which allows the operation of a VOR receiver in the presence of unwanted interference signals without sacrificing a fast response to omnirange bearing selector changes. A switching-type synchronous filter is used to filter the 30 Hz AM channel signal in the receiver. The narrow bandwidth of this synchronous filter rejects unwanted interference signals without introducing phase shift into the desired signal. The switching signal for the synchronous filter is generated by the FM channel in such a manner that the switching filter center frequency follows the input frequency. The use of a synchronous filter allows rejection of interfering AM signals that lie outside a narrow pass band, while allowing the receiver to follow variations in frequency of the transmitted signal.