Input signal recognition circuit
US4231016A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 27, 1978 |
| Grant date | Oct 28, 1980 |
| Priority date | — |
| Expiry date | Nov 27, 1998 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M11/003
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An input signal recognition circuit for a control system having an array of momentary switching elements (hereinafter referred to as "keys") whose number is larger than that of the array input terminals, which prevents erroneous control system operation which may occur upon simultaneous actuation of a plurality of keys. The control system with the input signal recognition circuit stably operates against key chattering and noise. The input signal recognition circuit comprises a keyboard including a plurality of keys arranged in a matrix, signals for sequentially sensing the actuation of keys on the respective columns of the matrix, an input buffer section which responds to the sensing signals to store the key data keyed in through the key actuation, a memory section for temporarily storing the key data and a recognition section for checking the contents of the memory section to detect whether any key has been actuated and for recognizing whether a plurality of keys in different columns of the matrix have been actuated. Only when a single key is actuated, or a plurality of keys in the same column are actuated, does the circuit identify that the input data is effective and generate a …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.