Waveshape memory type electronic musical instrument
AssigneeNippon Gakki Seizo Kabushiki Kaisha
InventorsYohei Nagai, Shimaji Okamoto
Life of this patent
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Abstract
A waveshape memory type electronic musical instrument produces a tone signal by cyclically reading wave value samples of a tone waveshape stored in a waveshape memory. The electronic musical instrument comprises a function generator for generating a periodic function signal which includes the mathematical product of an amplitude term varying as a function of time and a cyclic term of a selected frequency, and a multiplier for modulating a part of the tone waveshape by the periodic function signal, thereby producing a musical tone signal changing in waveshape as time lapses.
Claims9
A waveshape memory type electronic musical instrument including a waveshape memory which stores sample values of a waveshape defining a cycle of the waveshape, and producing a tone wave signal by repeatedly reading said sample values to constitute said waveshape at a frequency determined by the pitch of a tone to be sounded, the electronic musical instrument comprising:
- a function generator for generating a function wave signal;
- and
- means for modulating such ones of the read-out sample values that constitute a fractional part of said cycle of the waveshape of said tone wave signal generated from said waveshape memory by said function wave signal.
In a waveshape memory instrument of the type including a waveshape memory having stored therein sample values of a waveshape defining a cycle of said waveshape, means for repeatedly reading out said sample values at a frequency in accordance with the desired pitch of a tone to be sounded, envelope generator means, responsive to signals indicative of said read-out sample values, for generating output signals indicative of said read-out sample values multiplied by a predetermined attack/decay envelope function, and means, responsive to said envelope generator means output signals, for generating an audio tone, the improvement wherein said instrument further comprises:
- function signal generator means, for generating a time varying function signal;
- and
- multiplier means, responsive to said read-out sample values and said time varying function signal, for selectively multiplying a predetermined fractional portion of said sample values by said time varying function to generate thereby output signals indicative of said read-out sample values but having a predetermined fractional portion corresponding to said predetermined fractional portion of said read-out sample values which varies on a cycle-to-cycle basis, said multiplier means output signal being applied to said envelope generator means as said signal indicative of said read-out sample values.
Dependencies are inferred from the claim text.