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. 09, 2006
Filed:
Feb. 11, 1999
Kenichi Shiraishi, Yokohama, JP;
Atsushi Shinoda, Sagamihara, JP;
Kenichi Shiraishi, Yokohama, JP;
Atsushi Shinoda, Sagamihara, JP;
Kabushiki Kaisha Kenwood, Tokyo, JP;
Abstract
An AM neighboring interference removing method and circuit is provided which can select only a desired AM modulation wave even if an interference AM modulation wave is partially superposed upon the desired AM modulation wave. An AM modulation wave desired to be received is multiplied at multipliers by local oscillation signals having frequencies 3fc/2 and fc/2 where fc is the carrier frequency of a neighboring interference AM modulation wave. High frequency components contained in the outputs of the multipliers are removed by low-pass filters. Of the outputs of the low-pass filters, the carrier frequency of the neighboring interference wave is fc/2 and the AM carrier frequencies of the AM stereo modulation wave are (fc/2+fα) and (fc/2−fα), where fα is a difference frequency between the AM carrier frequency of the AM stereo modulation wave and the carrier frequency of the neighboring interference wave. A subtractor subtracts the output of one of the low-pass filter from the output of the other to thereby cancel out the neighboring interference wave. This subtraction signal is passed through a low-pass filter having a cut-off frequency of fc/2 to derive only the AM stereo modulation wave.