Patent Document ID: 4387622
Application ID: 06284744
Patent Flag: 1

Claim One:
1. In a keyboard musical instrument having a number of 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 a musical tone are computed during a sequence of computation cycles and are transferred sequentially to a digital-to-analog converter at a rate proportional to the pitch of the tone being generated, apparatus for generating tones having independent time-varying harmonic components comprising: a coefficient memory for storing a set of harmonic coefficient values, a first addressing means for reading out harmonic coefficient values from said coefficient memory, a formant clock for providing a sequence of format timing signals a curve memory for storing a plurality of sets of curve parameter values wherein each set of said sets of curve parameter values corresponds to one of said harmonic coefficient values, a first addressing means wherein a harmonic address signal is generated and whereby a harmonic coefficient value corresponding to said address signal is read out from said coefficient memory, a parameter addressing means responsive to said harmonic address signal whereby a plurality of curve parameter values is read out sequentially from said curve memory in response to said sequence of formant timing signals wherein said read out plurality of curve parameter values are from a set of curve parameter values corresponding to said harmonic address signal, a harmonic scale factor generation means whereby a sequence of harmonic scale factors are computed recursively in response to said parameter values read out sequentially from said curve memory to produce a sequence of time variant harmonic scale factor values corresponding to said harmonic address signal, a first multiplier means wherein said read out harmonic coefficient value is multiplied by said sequence of time variant harmonic scale factor values thereby producing a sequence of time variant harmonic coefficient values corresponding to each harmonic coefficient value read out from said coefficient memory, a means for computing, responsive to said sequence of time variant harmonic coefficient values corresponding to each harmonic coefficient value read out from said coefficient memory, whereby a master data set defining said waveform of a musical tone is generated during each one of said sequence of computation cycles, and a means for producing musical tones from said master data set having said independent time-varying harmonic components.