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. 12, 1988
Filed:
Apr. 29, 1986
Jacques Lewiner, 92210 Saint Cloud, FR;
Claude Hennion, 75013 Paris, FR;
Other;
Abstract
An electronic assembly is provided associated with a capacitive keyboard for identifying the depressed keys of this keyboard, which keys are disposed at the intersection points of a checkerboard pattern formed of m lines and n columns, comprising means for successively applying to the inputs of the m lines trains of n successive identical pulses, means for successively collecting at the outputs of the n columns the signals created by these pulses and means for detecting and identifying, among the signals collected, the echoes which exceed a predetermined threshold and which correspond to depressed keys, which means comprise a comparator for comparing the amplitude of said signals with that of a reference voltage. At all times, the comparison reference is related to the average in time of the mean of the amplitudes of the signals received at least two of the column outputs.