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:
Nov. 20, 1979
Filed:
Jul. 30, 1976
Applicant:
Inventor:
Arman V Dolikian, Palatine, IL (US);
Assignee:
Motorola, Inc., Schaumburg, IL (US);
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
H03K / ;
U.S. Cl.
CPC ...
328149 ; 307358 ; 329179 ; 3401 / ;
Abstract
The presence of a tone in a received signal is detected by passing the signal through a bandpass filter tuned to the frequency of interest. The output from the filter is peak detected and applied both to the first input of a comparator and to a unique variable threshold circuit which, in turn, is coupled to the remaining comparator input. The threshold circuit tracks the peak detected level of the bandpass filter output such that the comparator is activated between its logic states, representing the detect or undetect condition, with a minimum of delay time.