Tone generating system for electronic musical instrument

Abstract

This invention relates to tone generating systems for polyphonic electronic musical instruments. The system includes a plurality of programmable tone generators each of which is assigned to a different note to be sounded. For a preferred embodiment, one of the programmable tone generators is designated as a solo high tone generator, and is always utilized to produce the highest note to be sounded. Another generator may be designated as the solo low generator, and will always be utilized to generate the lowest note to be sounded. Additional solo note generators may be provided if desired. Tone generators are interconnected in a priority scheme with one generator at a time being designated as the next generator to be assigned a note to be sounded, and the designation being advanced in a predetermined manner as notes are assigned successively to the generators. One or more keyers are associated with each programmable tone generator, and receive a keyer enable signal from the tone generator when a note to be sounded is stored therein. Each generator also generates one or more pulse code outputs to its corresponding keyers, programming them to adapt to the selection of musical notes over a multi-octave range. Phase cancellation between two notes which are octavely related is avoided by duplicate generation of one of the notes in both master and slave tone generators, the code for any note being stored in both the master and slave generators whenever it is determined that the code for an octavely related note is already stored in another master generator. Various special effects are achieved by selectively dropping pulses from the clock signal applied to the programmable divider of the generator.