Patent ID: 7285715

Claim:
An estimator for a physical quantity expressing motion of a component part of a musical instrument, comprising: a data storage storing series of values of a piece of motion data expressing a sort of physical quantity varied on a trajectory on which said component part travels; and a data processor connected to said data storage, and determining another sort of physical quantity expressing said motion of said component part on the basis of said series of values of said piece of motion data through methods for estimating a value of said another sort of physical quantity by using equations different from one another and selectively used depending upon a characteristic of said motion, wherein said equations are expressed as PQ =1 /ΔT ×{( C 1 ×P 1 , . . . +Cn×Pn )/ M}, where PQ is said another sort of physical quantity, P 1 , . . . , Pn are said series of values of said piece of motion data, n is a natural number equal to the number of said values of said series, C 1 , . . . , Cn are coefficient for said P 1 to Pn different among said methods, M is a coefficient different among said methods and ΔT is a time interval between adjacent two of said series of values.