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:
Sep. 24, 1985
Filed:
Mar. 26, 1982
Commissariat a l'Energie Atomique, Paris, FR;
Abstract
Apparatus for suppressing interference in a capacitive keyboard. Unconditioned operating signals from receiving lines are passed into a subtractor, which establishes the difference between the signal present on a reference line in the keyboard and supplies, at the output, a conditioned operating signal which is free from any unwanted electromagnetic component which may have entered the structure. In addition, in order to determine which of several keys is supplying the highest signal, operating signals corresponding to particular receiving lines are scanned in sequence to determine which has the highest amplitude. As the operating signal corresponding to each successive key is scanned, its voltage is compared with a previously-stored voltage for an earlier-scanned key. If a higher voltage is detected, the voltage and key address are stored in place of the previously-stored values.