Electronic musical instrument capable of generating a chorus sound

In an electronic musical instrument having a keyboard with a plurality of keys and an output system adapted to receive tone signals and convert them into sound waves, a tone signal generator for generating a plurality of tone signals comprising:

• clock means comprising low frequency oscillator means for generating a series of timing pulses, a first phase lock loop responsive to said timing pulses for generating a first clock signal and a second phase lock loop responsive to said timing pulses for generating a second clock signal, said first and second phase lock loops including, respectively, first and second frequency dividers having division factors differing by an integral number of semitones;
• first and second top octave synthesizer means respectively connected for receiving said first and second clock signals for producing, respectively, first and second series of tone pulse signals, each of said series corresponding to a different tempered scale;
• divider means responsive to said first and second top octave synthesizer means for producing tone pulse signals octavely related to said first and second series of tone pulse signals;
• and
• means responsive to the operation of said keys for simultaneously supplying said output system with two tone pulse signals of approximately the same frequency derived individually from non-corresponding outputs of said first and second top octave synthesizer means, whereby the sound of a chorus is simulated.