| 摘要 |
PROBLEM TO BE SOLVED: To make the number of pitch names in use obtain at least a decided result of high degree of accuracy by counting the number of appearance of the pitch names out of the scale of each key and determining the key signature number by the key recording the smallest value. SOLUTION: The pitch name information determined by a pitch name detecting means 2 is inputted to plural out-of-scale counting means 3A, 3B, 3C,...3L. The out-of-scale counting means 3A-3L perform counting operation of the number of appearance of pitch names out of the scale of each key, respectively. The count values of the respective out-of-scale counting means 3A-3L are taken in a minimum value detecting means 4 and the order is detected from smaller count values. By detecting the order from smaller count values, the key of the out-of-scale counting means outputting the minimum value is specified as a first candidate and the kind # and the number of key signature are specified according to a prescribed table by means of the key allocated to the out-of-scale counting means 3A-3L in accordance with the successive order. |
