Control waveform generators for electronic musical instruments

A control waveform generator for an electronic musical instrument for generating a control waveform adapted to control at least one tonal element of a musical tone in response to the depression and release of a key among a plurality of keys, said musical tone including a tone pitch, a tone color and a tone volume, said control waveform generator comprising:

• a pulse generator for generating a pulse signal having a repetitive frequency;
• a detector including a counter which starts to count the number of said pulse signals in response to a key depression, said detector generating a first detection signal during an interval between a time corresponding to said key depression and a time at which a count of said counter reaches a target value and generating a second detection signal from a time when the counter counts the target value until a time corresponding to release of said depressed key;
• a capacitor, a terminal voltage of said capacitor being taken out as said control waveform;
• a first circuit responsive to said first detection signal for carrying out one of a charge operation and a discharge operation for said capacitor;
• a second circuit responsive to said second detection signal for carrying out the other of said charge and discharge operations for said capacitor;
• and
• a third circuit for carrying out said other one of said charge and discharge operations for said capacitor when said depressed key is released, thereby generating the control waveform represented by the terminal voltage of said capacitor, said tonal element being controlled in accordance with the control waveform.