Automatic adaptive selection of accompaniment tone controls for an electronic musical instrument

Claim 2

In a musical instrument having a number of tone generators, in which a plurality of data words corresponding to the amplitudes of points defining the waveform of a musical tone are computed and transferred sequentially to a digital-to-analog converter to be converted into audible musical tones, apparatus for selecting a combination of accompaniment musical tones from a library of accompaniment musical tones which complement a selected solo musical tone comprising: a coefficient memory for storing a set of solo harmonic coefficient values, a first means for computing a solo master data set comprising a plurality of data points defining the waveform of a solo musical tone from said stored set of solo harmonic coefficient values, a solo means for producing a solo musical tone from said solo master data set, a second means for computing responsive to said stored set of solo harmonic coefficient values whereby a set of autocorrelation function data values are computed, a plurality of accompaniment harmonic coefficient memories each storing a set of accompaniment harmonic coefficient values and a zero crossing value, an accompaniment addressing means for accessing a set of accompaniment harmonic coefficient values and a zero crossing value from each of said plurality of accompaniment harmonic coefficient memories, a tone selection means responsive to said set of autocorrelation values and each said zero crossing value accessed by said accompaniment addressing means whereby a multiplicity of selection numbers are generated, a third means of computing responsive to accompaniment harmonic coefficient values accessed from said plurality of accompaniment harmonic coefficient memories whereby an accompaniment master data set comprising a plurality of data points defining an accompaniment musical tone is computed, an harmonic selection means interposed between said plurality of accompaniment coefficient memories and said third means for computing whereby selected accompaniment harmonic coefficient values accessed by said accompaniment addressing means are transferred to said third means for computing in response to said multiplicity of selection numbers, and an accompaniment means responsive to said accompaniment master data set whereby said combination of accompaniment musical tones are produced which complement said solo musical tone.

Claim 3

A musical instrument according to claim 1 wherein said second means for computing comprises: a squarer means, responsive to said solo harmonic coefficient values read out from said coefficient memory whereby each of said solo harmonic coefficient values is multiplied by itself thereby producing a power coefficient value, a clock means for providing timing signals, a first counter means for counting said timing signals modulo a first specified number and wherein a first reset signal is generated when said first counter means returns to its initial count state, a second counter means incremented by said first reset signal wherein said second counter means counts modulo a second specified number, a first adder-accumulator means for successively adding the contents of said second counter means to a sum value contained in said first adder-accumulator means, a sinusoid table for storing a set of trigonometric function values, a first addressing means whereby a trigonometric function value is read out of said sinusoid table in response to the sum value contained in said first adder-accumulator means, a first multiplier means for multiplying the trigonometric function value read out from said sinusoid table by said power coefficient value to create an autocorrelation function component value, a means for accumulating each said autocorrelation function value thereby generating a sequence of autocorrelation function values, and a zero crossing means, responsive to said sequence of autocorrelation function values, wherein a zero crossing signal is generated when one of said sequence of autocorrelation function values has a positive numerical value and is followed in sequence by one of said sequence of autocorrelation function values which has a negative or zero numerical value.

Claim 4

In a musical instrument according to claim 2 wherein said zero crossing means comprises: an interpolation means whereby a solo zero crossing value is computed from said sequence of autocorrelation function values in response to said zero crossing signal, and a complementary generator means whereby a complementary zero crossing value is generated in response to said solo zero crossing value.

Claim 5

In a musical instrument according to claim 3 wherein said interpolation means comprises: a first register means for storing one of said sequence of autocorrelation function values, a second register means for storing an autocorrelation function value, a transferring means for transferring an autocorrelation function value from said first register means to said second register means, a subtracting means wherein a difference value is generated by subtracting the contents of said second register means from the contents of said first memory means, a divider means for driving said difference value by the content of said first register means to form a correction value, and an interpolation adder for adding the said correction value and the count state of said first counter means to form said zero crossing value in response to said zero crossing signal.

Claim 6

In a musical instrument according to claim 3 wherein said tone selection means comprises: a multiplicity of crossing storage means, a first comparison means whereby each said zero crossing value accessed from said plurality of accompaniment harmonic coefficient memories is furnished to one of said multiplicity of crossing storage means if said zero crossing value is not larger than said complementary zero crossing value, a second comparison means for selecting the maximum crossing value of all zero crossing values stored in said multiplicity of crossing storage means, an effective crossing computation means wherein effective crossing values are computed for said select maximum crossing value and each zero crossing value stored in said multiplicity of crossing storage means, a third comparison means for selecting the minimum value of said effective crossing values which is less in value than said complementary zero crossing value, and a tone encoding means wherein a first selection number is generated corresponding to one of said plurality of accompaniment harmonic coefficient memories from which said maximum crossing value is accessed and wherein a second selection number is generated corresponding to one of said plurality of accompaniment harmonic coefficient memories from which a zero crossing value is accessed corresponding to the minimal value selected by said third comparison means.

Claim 7

In a musical instrument according to claim 5 wherein said effective crossing computation means comprises: a first squaring means wherein said maximum crossing value is multiplied by itself to create a squared maximum crossing value, a second squaring means wherein each said zero crossing value stored in said multiplicity of crossing storage means is multiplied by itself to create a corresponding squared crossing value, an adder means for forming a sum value for said squared maximum crossing value added to said squared crossing value, and a square root means for evaluating the square root value of said sum value thereby generating said effective crossing value.

Claim 8

In a musical instrument having a number of keyboards comprising a plurality of keyswitches and having a number of tone generators, in which a plurality of data points defining the waveform of a musical tone are computed and transferred sequentially to a digital-to-analog converter to be converted into audible musical tones, apparatus for selecting a combination of accompaniment musical tones from a library of accompaniment musical tones which complement a selected solo musical tone comprising: a solo coefficient memory for storing a plurality of sets of solo harmonic coefficient values, a plurality of solo tone switches wherein each setting of the tone switches corresponds to a selection of a predetermined musical tone, a first addressing means responsive to the setting of said plurality of tone switches for reading out a corresponding set of solo harmonic coefficient values from said coefficient memory, a solo computing means responsive to said selected set of solo harmonic coefficient values for generating and storing a solo master data set having data values corresponding to a succession of points for said selection of a predetermined solo musical tone, an autocorrelation computing means wherein a set of autocorrelation function values are computed in response to said selected set of solo harmonic coefficient values read out from said solo coefficient memory, a zero crossing memory for storing a plurality of zero crossing values, a plurality of accompaniment tone switches wherein each setting of the accompaniment tone switches corresponds to a selection of a predetermined accompaniment musical tone, a second addressing means for reading out zero crossing values stored in said zero crossing memory, a tone selection means responsive to said set of autocorrelation function values and said read out zero crossing values whereby a multiplicity of selection numbers are generated, a tone setting means reponsive to said multiplicity of selection numbers whereby corresponding ones of said plurality of accompaniment tone switches are set, a solo tone generation means for generating said predetermined solo musical tone from said stored solo master data set, and an accompaniment tone generation means responsive to said setting of accompaniment tone switches whereby an accompaniment musical tone is generated which complements said predetermined solo musical tone.

Claim 9

In a musical instrument having a number of keyboards comprising a plurality of keyswitches and having a number of tone generators, in which a plurality of data points defining the waveform of a musical tone are computed and transferred sequentially to a digital-to-analog converter to be converted into audible musical tones, apparatus for selecting a combination of accompaniment musical tones from a library of accompaniment musical tones which complement a selected solo musical tone comprising: a solo coefficient memory for storing a plurality of sets of solo harmonic coefficient values, a plurality of solo tone switches wherein each setting of the tone switches corresponds to a selection of a predetermined musical tone, a first addressing means responsive to the setting of said plurality of tone switches for reading out a corresponding set of solo harmonic coefficient values from said coefficient memory, a solo computing means responsive to said selected set of solo harmonic coefficient values for generating and storing a solo master data set having data values corresponding to a succession of points for said selection of a predetermined solo musical tone, an autocorrelation computing means wherein a set of autocorrelation function values are computed in response to said selected set of solo harmonic coefficient values read out from said solo coefficient memory, a zero crossing memory for storing a plurality of zero crossing values, a plurality of accompaniment tone switches wherein each setting of the accompaniment tone switches corresponds to a selection of a predetermined accompaniment musical tone, a second addressing means for reading out zero crossing values stored in said zero crossing memory, a tone selection means responsive to said set of autocorrelation function values and said read out zero crossing values whereby a multiplicity of selection numbers are generated, a tone setting means reponsive to said multiplicity of selection numbers whereby corresponding ones of said plurality of accompaniment tone switches are set, a solo tone generation means for generating said predetermined solo musical tone from said stored solo master data set, and an accompaniment tone generation means responsive to said setting of accompaniment tone switches whereby an accompaniment musical tone is generated which complements said predetermined solo musical tone.

Claim 10

A musical instrument according to claim 7 wherein said autocorrelation computing means comprises: interpolation means whereby a zero crossing correlation spacing number is computed from each said set of autocorrelation values corresponding to an algebraic sign change between consecutive ones of said set of autocorrelation function values, and a crossing computing means responsive to said zero crossing correlation spacing number wherein a complementary zero crossing number is computed.

Claim 11

In a musical instrument according to claim 8 wherein said tone selection means comprises: a maximum number selection means whereby the largest of said plurality of zero crossing values which is less in magnitude than said complementary zero crossing number is selected, a first encoding means whereby a first selection number is generated corresponding to the zero crossing value selected by said maximum number selection means, an effective crossing computation means whereby a set of effective zero crossing numbers are generated in response to the zero crossing value selected by said maximum number selection means and each zero crossing value read out of said zero crossing memory, and a second encoding means whereby a second selection number is generated corresponding to the maximum one of said effective zero crossing numbers which is less than the value of said complementary zero crossing number.