Circuit preventing phantom input in a switch matrix
US4599608A · kind A · utility
10Cited by
5References
14Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Mar 21, 1983 |
| Grant date | Jul 8, 1986 |
| Priority date | — |
| Expiry date | Mar 21, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M11/003
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
In an information processing apparatus with an input device in the form of a keyboard, a multiplicity of switches associated with input keys on the keyboard are disposed in independent submatrices. When three or more keys in each submatrix are operated simultaneously, key input detection is stopped. The number of switches which are turned on in each scanning is registered and when the number is two at the most, addresses representative of the switches which are turned on are delivered out for inputting information. Key input at high speeds can be permitted and erroneous input can be prevented.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.