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:
Jul. 26, 2005
Filed:
May. 02, 2002
Applicant:
Hiroshi Kawakatsu, Suita, JP;
Inventor:
Hiroshi Kawakatsu, Suita, JP;
Assignee:
Nohken Inc., Osaka, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01R027/02 ; G01H001/00 ;
U.S. Cl.
CPC ...
Abstract
A triangular wave generating circuit () generates a sweep voltage of a triangular wave, a VCO () generates a sweep of a frequency according to the sweep voltage, and a driving coil () is driven by the sweep voltage. From the current flowing through the driving coil (), an interference component is extracted and rectified by a rectifier circuit (). A peak hold circuit () holds a peak value of an interference voltage within a period corresponding to one sweep. The peak value thus held is compared by a comparator circuit () with a predetermined value and accordingly, a relay circuit () outputs a signal indicative of whether an object is present or not.