Wavetable audio synthesizer with waveform volume control for eliminating zipper noise
US5742695A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 2, 1994 |
| Grant date | Apr 21, 1998 |
| Priority date | — |
| Expiry date | Nov 2, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10H2250/621
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A wavetable audio synthesizer with means for eliminating zipper noise caused by large volume increments, especially at slower rates of volume increment. The wavetable audio synthesizer includes shift circuitry which stores the value of volume increment in binary format and shifts the value right when the shift circuitry is enabled. Shifting the increment value right divides the value by an amount based on the number of bit positions shifted. For example, in the preferred embodiment, the volume increment value is shifted right three positions, thereby dividing it by three and effectively reducing the increment value. When the synthesizer is programmed to increment the volume at a slow rate, preferably the shift circuitry is automatically enabled. Those volume increment bits which are shifted right may be added to the current value of the volume to provide more resolution to this value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.