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:
Dec. 30, 1986
Filed:
May. 21, 1985
Applicant:
Inventor:
Heinrich Pfeifer, Denzlingen, DE;
Assignee:
Deutsche ITT Industries GmbH, Freiburg, DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04B / ;
U.S. Cl.
CPC ...
455228 ; 455 45 ; 340905 ; 34082548 ;
Abstract
An essentially digital circuit is disclosed in which a demodulated broadcast signal is digitized by an analog-to-digital converter and processed in three signal paths each including a tuned filter. The tuned filters have closely adjacent resonance frequencies, the same resonance curves, and the same resonance rises. The signals at the outputs of these three signal paths are so evaluated by means of four comparators and an RS flip-flop that the message tone signal appears at the Q output of the flip-flop only in the presence of the message tone frequency.