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:
Apr. 16, 2002
Filed:
Oct. 08, 1999
Toshiyuki Matsumoto, Hyogo-ken, JP;
Yoshihiro Hirota, Kyoto, JP;
Muneo Harada, Hyogo-ken, JP;
Takaya Miyano, Aomori-ken, JP;
Sumitomo Metal Industries, Ltd., Osaka, JP;
Abstract
An apparatus for detecting an impedance variable in response to a sensed physical amount of a sensor is provided which comprises an impedance-frequency conversion unit and a counter. The impedance-frequency conversion unit converts the sensor impedance to an oscillation signal a frequency of which corresponds to the sensor impedance. The impedance-frequency conversion unit comprises an impedance-voltage converter for providing a voltage corresponding to the sensor impedance, and a Wien bridge oscillator including an element an impedance of which varies in response to the voltage from the impedance-voltage converter, for generating the oscillation signal. The Wien bridge oscillator is capable of generating a square wave signal as the oscillation signal. The counter counts the number of waves (or wave number) of the oscillation signal in a predetermined time period to output a count value which can be handled as a digital signal.