Tone generator assignment in a keyboard electronic musical instrument

In combination with a keyboard musical instrument comprising a keyboard array of a number of keyswitches and having a plurality of tone generators smaller in number than the number of keyswitches in said keyboard array, apparatus for assigning members of said plurality of tone generators to actuated keyswitches in a manner such that a tone generator is always assigned to the latest actuated keyswitch comprising;

• a keyswitch state detect means wherein a detect signal is generated in response to each actuated keyswitch in said keyboard array of keyswitches,
• an encoding means for encoding each said detect signal to generate a detect data word which identifies each said actuated keyswitch corresponding to a generated detect signal,
• an assignor means responsive to each said detect data word whereby one of said plurality of tone generators is assigned to generate a musical tone associated with a corresponding keyswitch contained in said keyboard array of keyswitches,
• a tone generator counter incremented by each said detect data word,
• a comparator means responsive to the count state of said tone generator counter whereby if said count state has attained a prespecified maximum value a kill signal is generated in response to an additional data detect word
• a tone generator remove means responsive to said kill signal whereby a detect data word supplied to said assignor means is replaced by said additional data select word.

In combination with a keyboard musical instrument, having a keyboard array of keyswitches, in which a plurality of data words corresponding to the amplitudes of points defining the waveform of a musical tone are computed during each one of a sequence of computation cycles and transferred to a plurality of tone generators smaller in number than the number of keyswitches in said keyboard array, apparatus for assigning members of said plurality of tone generators to actuated keyswitches in a manner such that a tone generator is always assigned to the most recently actuated keyswitch comprising;

• a keyswitch state detect means wherein a detect signal is generated in response to each actuated keyswitch in said keyboard array of keyswitches,
• an encoding means for encoding each said detect signal to generate a detect data word which identifies each said actuated keyswitch corresponding to a generated detect signal,
• a means for computing whereby said plurality of data words corresponding to the amplitudes of points defining the waveform of a musical tone are computed,
• a plurality of tone generators each of which produces a musical waveshape in response to said plurality of data words computed by said means for computing,
• an assignor means responsive to each said detect data word whereby one of said plurality of tone generators is assigned and caused to generate said musical waveshape at a frequency associated with a corresponding keyswitch contained in said keyboard array of keyswitches,
• a tone generator status means whereby a kill signal is generated if all of said plurality of tone generators have been assigned to generate musical waveforms and an additional data detect word is generated, and
• a tone generator remove means responsive to said kill signal whereby a detect data word supplied to said assignor means is replaced by said additional data select word.

In combination with a keyboard musical instrument, having a keyboard array of keyswitches, in which a plurality of data words corresponding to the amplitudes of points defining the waveform of a musical tone are computed during each one of a sequence of computation cycles and transferred to a plurality of tone generators smaller in number than the number of keyswitches in said keyboard array, apparatus for assigning members of said plurality of tone generators to actuated keyswitches in a manner such that a tone generator is always assigned to the most recently actuated keyswitch comprising;

• a keyswitch state detect means wherein a detect signal is generated in response to each actuated keyswitch in said keyboard array of keyswitches,
• an encoding means for encoding each said detect signal to generate a detect data word which identifies each said actuated keyswitch corresponding to a generated detect signal,
• a means for computing whereby said plurality of data words corresponding to the amplitudes of points defining the waveform of a musical tone are computed,
• a plurality of tone generators each of which produces a musical waveshape in response to said plurality of data words computed by said means for computing,
• an assignor means responsive to each said detect data word whereby one of said plurality of tone generators is assigned and caused to generate said musical waveshape at a frequency associated with a corresponding keyswitch contained in said keyboard array of keyswitches,
• a tone generator counter incremented by each said detect data word,
• a comparator means responsive to the count state of said tone generator counter whereby if said count state has attained a prespecified maximum value then a kill signal is generated in response to said additional data detect word and,
• a tone generator remove means responsive to said kill signal whereby a detect data word supplied to said assignor means is replaced by said additional data select word.

In combination with a keyboard musical instrument, having a keyboard array of keyswitches, in which a plurality of data words corresponding to the amplitudes of points defining the waveform of a musical tone are computed during each one of a sequence of computation cycles and transferred to a plurality of tone generators smaller in number than the number of keyswitches in said keyboard array, apparatus for assigning members of said plurality of tone generators to actuated keyswitches in a manner such that a tone generator is always assigned to the most recently actuated keyswitch comprising;

• a keyswitch state detect means wherein a detect signal is generated in response to each actuated keyswitch in said keyboard array of keyswitches,
• an encoding means for encoding each said detect signal to generate a detect data word which identifies each said actuated keyswitch corresponding to a generated detect signal,
• a means for computing whereby said plurality of data words corresponding to the amplitudes of points defining the waveform of a musical tone are computed,
• a plurality of tone generators each of comprises, a note memory means for storing said plurality of data words computed by said means for computing, a slave memory means for storing said plurality of data words, a note clock for providing timing signals at a rate determined by said assignor means, a first memory address means responsive to said timing signals whereby a repetitive sequence of memory address numbers are generated and whereby data words are accessed from said note memory means in response to said memory address numbers, a second memory address means responsive to said sequence of memory address numbers whereby data words are accessed from said slave memory means, an adder for adding said data words read out from said note memory means with said data read out from said slave memory means to create a summed sequence of data words in response to an add signal, a converter means whereby said summed sequence of data words is converted into an audible musical tone,
• an assignor means responsive to each said detect data word whereby one of said plurality of tone generators is assigned and caused to generate said musical waveshape at a frequency associated with a corresponding keyswitch contained in said keyboard array of keyswitches,
• a tone generator status means whereby a kill signal is generated if all of said plurality of tone generators have been assigned to generate musical waveforms and an additional data detect word is generated,
• an event sequencer means whereby each of said detect data words are stored in an ordered sequence arranged in the time order in which the keyswitches corresponding to each said detect data word are actuated and wherein said arrangement identifies the oldest data detect signal, and
• a phase means whereby in response to said kill signal the waveshape produced by one of said plurality of tone corresponding to said oldest data detect signal is reduced in amplitude and whereby a done signal is generated when said waveshape has attained a minimum value.