Digital music synthesizer

Abstract

The system of this invention is for use with an electronic musical instrument having a keyboard, and generally includes keyboard circuitry, audio waveform generators, envelope generators, static and dynamic filter circuitry and power amplifier and speaker apparatus. In accordance with one feature of this invention, the system comprises means for establishing different digital voice codes which are coupled to read only memories associated with the audio waveform generators, envelope generators and main voice circuitry. This voice code provides a limited number of program conditions to control such variables as audio waveform pulse widths, envelope attack, decay, sustain or release intervals, and instrument resonator control. Another feature of the present invention is concerned with the keyboard circuitry which operates from a digital key and octave code. Each code is sequentially interrrogated to determine if the corresponding key has been played. Although the completely illustrated embodiment is of a monophonic system, this sequential interrogation scheme lends itself quite readily to polyphonic operation. Still another feature of the invention resides in a novel digital controlled oscillator of the audio waveform generators that includes a feedback control loop and wherein the majority of the components of the oscillator only operate over a one octave range.

Dependencies are inferred from the claim text.