Transient voice generator
AssigneeDeutsch Research Laboratories, Ltd.
InventorRalph Deutsch
Life of this patent
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Abstract
Musical notes having time variant modification of the waveshape are produced polyphonically in a tone synthesizer by computing master and transient data sets, transferring these data to buffer memories, adding the data read out from the buffer memories briefly during a transient time interval and repetitively converting the summed data to waveforms. The master and transient data set are created repetitively and independently of tone generation by computing a generalized Fourier algorithm using stored sets of generalized Fourier coefficients. Circuitry is disclosed for independently applying Attack/Release modulations to the principal tone generated from the master data set and to the transient tone generated from the transient data set.
Claims9
In a musical instrument of the type including a keyboard having a plurality of key-operated switches, a plurality of tone setting stop switches, generation means for synthesizing a musical waveshape by calculating its constituent generalized Fourier components and wherein each Fourier component is established by a harmonic coefficient associated with the corresponding Fourier component, said generation means including first circuitry operative during a computation cycle for individually calculating the constituent Fourier components and an accumulator for summing these Fourier components to form a master data set in which the relative values of the words are established by a set of harmonic coefficients selected in response to the setting of said stop switches and second circuitry having a plurality of registers for receiving transferred master data set words, and a convertor means for generating analog output musical waveshapes from data read out of registers by associated clock generators;
- the improvement for time variant modification of the synthesized musical waveshapes comprising;
- means for computing a master data set and a transient data set during a computation cycle,
- a first storage means comprising a first memory means for writing said master data set to be thereafter read out and a second memory means for writing said transient data set to be thereafter read out,
- a third memory means for writing input data to be thereafter read out,
- means for repetitiously reading out data stored in said first storage means at selected rates,
- a transient signal control generator wherein a select signal is created in response to actuation of said key-oriented switches, and
- select means responsive to said select signal whereby data is selectively read out from said first memory means or is selectively read out from said second memory means and the selected data is transferred and caused to be written into said third memory means thereby producing said time variant modification of the synthesized musical waveshape.
Dependencies are inferred from the claim text.