| 摘要 |
Clavier multiplexing is used in the present keyboard musical instrument to reduce the number of sound generators needed by connecting them only to those notes that are depressed. The association of a tone generator with a control unit, which provides the tone generator with frequency, force, and speed information, continues as long as possible, and even after the associated note is released and until the control unit is needed to attend another note by use of independent address and idle-busy storage registers. The note address is digitally designated and remembered, sequential start up logic is used for a control unit. In the glissando mode, the address of the note of the pair involved in the glissando that was released last must be remembered, and the voltage-controlled oscillator involved must have continuing access to this address. A fixed priority rule for nonpercussive timbres and age-dependent rule for percussive timbres is used to select control units, thus enabling multiple glissandos and the control of different tone colors from the same clavier, the latter employing additionally suppression switches. The lockouts can be stacked thereby facilitating the addition of control units on a modular basis, so that any desired plurality may be achieved. Subdivision of the key interrogation interval into two parts enables the sensing of force of key depression and sidewise motion, which is used to provide vibrato, separately, capacitive keying being used in each case. A resistor in the feedback loop of the integrator of a voltage-controlled oscillator compensates for the reset time of the integrator. The digital-to-analog converter and voltage-controlled oscillators are tied together with feedback such that the frequencies of the oscillators are dependent primarily upon resistor ratios, and not power supply potentials.
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