Abstract: 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.

Abstract: An automatic accompaniment system for use with an electronic musical instrument of a type having keyboard arrangements, which is capable of automatically sounding chords and basses in accordance with a predetermined rhythm of a selected music, the basses of which are each formed by some of tones forming each chord in the case where the right and left hands of a player are used to play the melody and an accompaniment, respectively. To this end, the system includes a counting circuit composed of a binary counter and a decoder, a high frequency pulse generator, a plurality of logical gating elements and a rhythm pulse generator.