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. 25, 1981
Filed:
Oct. 03, 1979
Kazuhiko Takaoka, Tokyo, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A multi-frequency signal receiving apparatus for receiving signals with at least more than two frequencies and selectively separating these signals, comprising a first maximum value detecting means for detecting the maximum value of the rectified outputs of a plurality of channel filters provided for said signals to be selected; a second maximum value detecting means for detecting the maximum value of the rectified outputs at the intermediate stage of two channel filters for discriminating the signals at both ends of the signal frequency bands of a plurality of said channel filters; and a comparison means for comparing the outputs of said first and second maximum value detecting means with an appropriate weight and thereby detecting the presence or absence of the signal to be detected; whereby based on the result of comparison, the threshold value of discriminators placed at the succeeding stage of said channel filters for discriminating the predominant frequency signal is controlled. The invention thus permits the elimination of input filers, and realizes an economical and reliable signal receiver.