Wavetable audio synthesizer with low frequency oscillators for tremolo and vibrato effects
US5668338A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 2, 1994 |
| Grant date | Sep 16, 1997 |
| Priority date | — |
| Expiry date | Nov 2, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10H2250/611
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A digital wavetable audio synthesizer with an LFO generator is described. The synthesizer can generate up to 32 high-quality audio digital signals or voices, including delay-based effects. The synthesizer includes an address generator which has several modes of addressing wavetable data. The address generator's addressing rate controls the pitch of the synthesizer's output signal. A synthesizer volume generator, which has several modes of controlling the volume, adds envelope, right offset, left offset, and effects volume to the data. The synthesizer LFO generator can add LFO variation to: (i) the wavetable data addressing rate, for creating a vibrato effect; and (ii) a voice's volume, for creating a tremolo effect. The LFO generator assigns two triangular-wave LFOs to each of the 32 possible voices. One LFO is dedicated to vibrato (frequency modulation) effects and the other to tremolo (amplitude modulation) effects. It is possible to ramp the depth of each LFO into and out of a programmable maximum. The parameters for each LFO are stored in local memory. When creating delay-based effects, data is stored in one of several effects accumulators. This data is then written to a waveta…
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