Apparatus for tone generation with combined loudness and formant spectral variation
AssigneeKawai Musical Instrument Mfg. Co., Ltd.
InventorRalph Deutsch
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Abstract
In a musical instrument having one or more tone generators in which a plurality of data words corresponding to the amplitudes of a corresponding number of evenly spaced points defining the waveform of one cycle of an audio signal are transferred sequentially from a note register to a digital-to-analog converter in repetitive cycles at a rate proportional to the pitch of the tone being generated, apparatus is provided for varying the spectral content of the tone in response to control signals. A loudness control signal causes loud tones to be produced with a greater number of harmonics than those for a soft tone. A formant control signal also causes the tones to have a time variant spectral quality.
Claims11
In a musical instrument having one or more tone generators in which a plurality of data words corresponding to the amplitudes of a corresponding number of evenly spaced points defining the waveform of an audio tone are computed and in which the data words are transferred sequentially from a note register to a digital-to-analog converter at a rate proportional to the pitch of the tone being generated, apparatus for generating tones having a variable spectral content comprising;
- a first means for computing transfer data values during the first subcomputation cycle of a sequence of computation cycles each comprising a first and second subcomputation cycle,
- a first memory means for storing said transfer data values to be thereafter read out,
- a second memory means for storing a master data set comprising a plurality of data points to be thereafter read out,
- a signal generating means for generating a control signal,
- a first addressing means responsive to a control signal whereby said transfer data values are read out from said first memory means and stored in said second memory means during said second subcomputation cycle,
- a note register means for storing data values to be thereafter read out,
- a data transfer means whereby said master data set is read out from said second memory means and wherein said master data points are translated in magnitude to produce a translated master data set having a zero average value which is stored in said note register means,
- a second addressing means for sequentially and repetitively reading out data stored in said note register means, and
- means for producing musical signal waveshapes from data read out from said note register means.
A digital polyphonic tone synthesizer in which tones of variable spectral content are generated in response to control signals comprising;
- a keyboard comprising a plurality of keyswitches,
- a plurality of tone switches wherein each setting of the tone switches corresponds to the selection of a musical tone,
- a means for computing transfer data values during a computation cycle of a sequence of computation cycles,
- a first memory means for storing said transfer data values,
- a signal generating means for generating a control signal,
- an addressing means responsive to a control signal for addressing out transfer data values from said first memory means, said transferred data values comprising a master data set,
- a second memory means for storing said master data set,
- a plurality of note register memory means,
- transfer means whereby master data set stored in said second memory means is read out, translated in magnitude to have a zero average value, and transferred to be stored in selected members of said plurality of note register memory means,
- a plurality of variable frequency clock generators, each associated with a member of said plurality of note register memory means, whereby data is addressed out of said associated note register memory means at a selected clock rate,
- means responsive to operation of any member of said plurality of keyswitches for setting the frequencies of said variable frequency clock generators to predetermined values assigned to said key switches,
- digital-to-analog converter means connected to said plurality of note register means, and
- means for repetitively and sequentially reading data from each of said plurality of note register means and providing data to said digital-to-analog converter means in synchronism with said associated variable frequency clock generator, whereby said digital-to-analog converter means generates a plurality of analog output signals each having a fundamental frequency determined by a selected key on said keyboard and a waveshape determined by the combination of the setting of said tone switches and the magnitude of said first control signal.
Dependencies are inferred from the claim text.