Single bus keyboard
US4136595A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 19, 1976 |
| Grant date | Jan 30, 1979 |
| Priority date | — |
| Expiry date | Oct 19, 1996 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S84/08
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
An inexpensive single bus keyboard circuit for voltage controlled electronic musical instruments. The keyboard signal voltage is sampled and stored after each depression of a key, or release of a key when other keys are held in a depressed state, and a gate detector is provided to prevent sampling and change of stored voltage when all keys are released, to thereby insure that the last stored signal voltage is retained when all keys are released. A program counter establishes the timing relationships between the generated control signals and provides adaptive timing to prevent response to spurious key switch signals. The circuit distinguishes in a simple manner between keyboard sample voltages corresponding to the depression of one or more keys and those corresponding to the condition in which no keys are depressed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.