US 4,498,363 AGranted

Just intonation electronic keyboard instrument

AssigneeVictor Company of Japan, Ltd.

InventorsKengo Shimada, Yutaka Chiba, Toshio Sanuki

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Abstract

A just intonation electronic keyboard instrument comprises a plurality of tonality selection switches for selecting each key from among twenty-four just intonation keys, a control circuit for determining one or a plurality of just intonation keys according to the manipulation of said switches, a variable frequency oscillator having its output oscillation frequency varied in accordance with the selected key, and a frequency dividing circuit having frequency dividers which are varied of their frequency dividing ratios according to the selected key. The number of tonality selection switches is less than twenty-four. The control circuit discriminates the selection to a major scale or a minor scale, and discriminates one or a plurality of keys from each of twelve keys from C through B, and determines one or a plurality of selected just intonation keys, according to the manipulation of said intonation selection switches. The variable frequency oscillator produces an output oscillation frequency which is an integral multiple of a frequency of a key-note of the determined key. The frequency dividing ratios of the frequency dividers are respectively varies so that ratios among frequency dividing ratios are in accordance with a temperament of the determined just intonation key.

Claims14

Dependent claims

A just intonation electronic keyboard instrument comprising:

a plurality of tonality selection switches for selecting each key from among twenty-four different just intonation keys, number of said tonality selection switches being less than twenty-four;
control means for discriminating selection of a major scale or a minor scale, discriminating one or a plurality of keys among each of twelve keys from C through B, and determining one or a plurality of keys from among said twenty-four just intonation keys, according to manipulation of said plurality of tonality selection switches;
variable frequency oscillator means responsive to the determined one or plurality of keys among said twenty-four just intonation keys, for generating an output oscillation frequency so that the output oscillation frequency is equal to a frequency which is an integral multiple of a frequency of a key-note of the key determined by said control means;
and
frequency dividing means comprising a plurality of frequency dividers respectively provided in correspondence with each of instrument keys of a keyboard for play,
each of said plurality of frequency dividers being supplied with the output of said variable frequency oscillator means,
each of frequency dividing ratios of said frequency dividers being varied so that ratios among the frequency dividing ratios are in accordance with a temperament of just intonation key determined by said control means.

4 more elements

Dependencies are inferred from the claim text.