Keyboard operated electronic musical instrument

摘要

A keyboard operated electronic musical instrument such as an electronic organ is disclosed which generates a musical tone signal by mixing together two different musical tone signals of different waveforms and which changes the sound of the generated musical tone by changing a the amount of mixing of the two signals. A clipping gate with a so-called sustain function is included for controlling the attenuation of an input signal as it passes to an output terminal while clipping the input signal gradually and smoothly so that the musical tone does not disappear instantly but attenuates gradually after the release of a depressed key. The input signal to the clipping gate circuit is a square wave signal, and a square wave signal derived at an output thereof is converted to a waveform other than a square wave. When the square wave signal and the non-square wave signal are used as the two different musical tone signals, an unintended change of tone is prevented by designing the system to avoid an abrupt change in the musical tone signal between a sound generated when a key is depressed and an attenuating sound generated when the key is released.