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:
Oct. 29, 1996
Filed:
Aug. 26, 1993
Masaki Tokioka, Yokohama, JP;
Atsushi Tanaka, Kawasaki, JP;
Yuichiro Yoshimura, Kamakura, JP;
Kiyoshi Kaneko, Yokohama, JP;
Ryozo Yanagisawa, Matsudo, JP;
Katsuyuki Kobayashi, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
Vibration applied to a tablet is sensed by a sensor provided on the tablet and a time delay from generation of the vibration to the sensing thereof is measured, whereby distance from the vibration source to the sensor can be measured. If the vicinity of the leading edge of the envelope of registration is sensed when sensing the vibration, the effects of reflected waves from the periphery of the tablet are reduced. To this end, the envelope is differentiated to detect an inflection point. The peak gain frequency of the differentiating circuit is greater than the frequency of vibration generated by the vibration source. As a result, the phase of the output signal produced by the differentiating circuit is advanced by about .pi./2 with respect to the phase of the input signal, thereby making it possible to sense vibration more quickly.