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:
Aug. 10, 1976
Filed:
Oct. 29, 1974
Glen R Griffith, Westminster, CA (US);
Ralph Deutsch, Sherman Oaks, CA (US);
Nippon Gakki Seizo Kabushiki Kaisha, Hamamatsu, JA;
Abstract
In this key switch scanning and encoding system, open (OFF) switches may be scanned at a faster rate than closed (ON) switches, and a coded signal is produced indicative of each closed switch. The switches are arranged in a matrix of M groups each connected to N common output lines. The switch groups are enabled sequentially, one at a time. As each group of switches is enabled, the N output lines sequentially are gated to a coding matrix. If the gated line is associated with a closed switch in the enabled group, an output code is produced by the code matrix, which, together with a signal designating the enabled group, uniquely identifies the closed switch. Scanning is delayed briefly to permit utilization of the encoded output. If an open (OFF) switch is scanned, no code is produced by the code matrix. This no-code condition immediately causes the next switch matrix output line to be gated to the code matrix. In this way, open switches are 'skipped over' or scanned at a rapid rate. The system is particularly useful in an electronic musical instrument.