Control waveform generators for electronic musical instruments

摘要

In a control waveform generator for an electronic musical instrument of the type wherein the generator generates a control waveform adapted to control at least one of a tone pitch, a tone color and a tone volume, the control waveform generator is constituted by a pulse generator for generating a pulse signal having a repetitive frequency, and a detector including a counter which starts to count the number of the pulse signals when a key is depressed. The detector generates a first detection signal during an interval between depression of the key and a time at which a counter reaches a predetermined value and then produces a second detection signal until the depressed key is released. The control waveform generator further comprises a capacitor whose terminal voltage is taken out as the control waveform, a first charging or discharging circuit responsive to the first detection signal for charging or discharging the capacitor, a second discharging or charging circuit responsive to the second detector signal for discharging or charging the capacitor, and a third discharging or charging circuit for discharging or charging the capacitor when the depressed key is released.