Key depression number processing system for keyboard circuit
US4472991A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 16, 1982 |
| Grant date | Sep 25, 1984 |
| Priority date | — |
| Expiry date | Sep 16, 2002 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S84/02
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
Key switches of a keyboard circuit are scanned by a counter which starts at a lower or upper limit value that is preset in the counter by a signal which also reverses the counting direction data from the counter, is provided to a first circuit having preset therein the number of preferential low-pitched or high-pitched tones to be produced and a second circuit having preset therein a maximal number of tones to be produced. In the case where the number of preferential low-pitched tones is preset in the first circuit, and when the number of tones based on the data from the counter reaches the preset number, the direction of counting of the counter is reversed by the signal to cause the counter count down starting with the preset upper limit value. In the case where the number of preferential high-pitched tone productions is preset in the first circuit, and when reaching the preset number, the direction of counting of the counter is inverted to cause it to count up from the preset lower limit value. When the number of simultaneous key depressions exceeds the maximal number of tones allowed by the second circuit, the processing causes middle-pitched tones to be eliminated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.