PURPOSE: To provide the automatic key controller for the orchestral accompaniment device which can automatically perform key control.
CONSTITUTION: An accompaniment frequency extracting means 10 extracts digital frequency signals of an accompaniment signal and a 1st arithmetic means 14 adds the respective digital frequencies within a measurement time to obtain the sum frequency. A song frequency extracting means 12 extracts digital frequency signals of a song signal and a 2nd arithmetic means 16 adds the respective digital frequencies within the measurement time to obtain the sum frequency. Then a 3rd arithmetic means 18 calculates the difference frequency between the sum frequency of the accompaniment frequency and the sum frequency of the song signal in each measurement time and a selecting means 20 selects the difference frequency having the highest frequency in a performance time. A key correcting means 22 corrects the key of the accompaniment according to deviation in the key corresponding to the selected difference frequency. For the purpose, the deviation between the key of the song and the key of the accompaniment is detected and the key of the accompaniment is corrected according to the deviation in key to put the controller in operation.
NOZOE KAZUJI
ITO MIYOSHI
TOSHIBA EMI KK
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