Musical instrument and method for generating musical sound
AssigneeThe Board of Trustees of the Leland Stanford Junior University
InventorJames A. Moorer
Life of this patent
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Abstract
Disclosed is a musical instrument and method for generating musical sound. Digital circuits produce a sequence of numbers which are converted to analog electrical signals which are periodically sampled to drive a conventional speaker. The digital circuits operate in accordance with a method of forming each sample by evaluation of a closed-form expression including a first function of time, either periodic or non-periodic, transformed by a second function of time where the second function is non-linear, non-sinusoidal and differs from the first function. The frequency spectra of the resulting musical sound can be finite and the amplitudes of frequency components do not have unwanted limitations.
Claims16
A musical instrument for producing musical sound comprising,
- a keyboard for specifying a frequency and duration of a musical sound to be generated,
- an initial data memory storing initial data and responsive to the keyboard for initializing the musical instrument,
- a spectral control unit for storing a time-varying spectral index,
- an amplitude control unit for storing a time-varying amplitude index,
- a first function memory for storing data for a first function,
- a second function memory for storing data for a second function when said second function is non-linear and is different from said first function,
- arithmatic means for combining signals from said memories and units,
- control means for providing control signals to said memories, units and arithmatic means in accordance with a control sequence to produce periodically digital signals as the non-linear transformation of said first function by said second function and where said digital signals specify an amplitude controlled by said amplitude index and a frequency spectra controlled by said spectral index,
- means for generating musical sound in response to said digital signals whereby the musical sound has an amplitude and component frequencies determined by the amplitude and frequency spectra of said digital signals.
A musical instrument for producing musical sound comprising,
- a keyboard for specifying a frequency and duration of a musical sound to be generated,
- an initial data memory storing initial data and responsive to the keyboard for initializing the musical instrument,
- a spectral control unit for storing a time-varying spectral index,
- an amplitude control unit for storing a time-varying amplitude index,
- a first function memory for storing data for a first function,
- a second function memory for storing data for a second function where said second function is a non-linear and is different from said first function,
- a scratch pad memory,
- arithmatic means for arithemetically combining signals from said memories and units,
- control means for providing control signals to said memories, units and arithmatic means in accordance with a control sequence to produce, periodically at a sample period, digital signals as the non-linear transformation of said first function by said second function and where said digital signals determine an amplitude controlled by said amplitude index and a frequency spectra controlled by said spectral index,
- generator means for generating musical sound in response to said digital signals whereby the musical sound has an amplitude and component frequencies determined by the amplitude and frequency spectra determined by said digital signals, said generator means including means for converting one of said digital signals to an analog signal each sampling period.
Dependencies are inferred from the claim text.