The Wurlitzer Company

Acoustic Standards Corporation

Carl P Oppenheimer

Thomas A Niezgoda

A programmable tone generator for an electronic musical instrument generates a tone signal having a desired fundamental frequency and harmonic content. A binary counter serves as a time base for encoding each period of a tone signal waveform onto plural outputs in the form of a binary code. A plurality of programmable tone generation circuits are coupled with selected counter outputs to comprise plural tone signal branches, each providing a tone signal at a selected fundamental frequency and having selected harmonic content. A signal processing circuit associated with each tone signal branch includes a programmable variable code generator and determines the initial content of the output waveform, subsequently either maintaining or changing the fundamental frequency and harmonic content thereof.

Programmable tone generator

A tone generation system is intended for use with an electronic musical instrument of the type wherein an audible tone is generated electronically in response to actuation of the instrument by a player. The invention generates digital signals capable of defining either the waveshape or the envelope or characteristic of a tone for each tone initiated by such player actuation the latter envelope being varied in accordance with the intensity of the player actuation initiating that tone. In the latter case, digital electronic circuits are utilized for developing a digital scaling signal S corresponding to the intensity of actuation of the instrument by the player, and a digital envelope signal which represents slopes and Y intercepts of portions of a composite waveform, viewed in an orthogonal coordinate system. These digital circuits arithmetically manipulate these scaling signals and envelope signals to give a composite output signal defining the envelope.

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Sycamore, IL, United States of America

Carl P Oppenheimer