| 摘要 |
PROBLEM TO BE SOLVED: To provide an approximation circuit finding an approximation value of a non-linear function by high-speed hardware processing. SOLUTION: This approximation circuit approximating the non-linear function, in which an output value is varied non-linearly with respect to an input value, by approximation straight lines in a plurality sections is provided with an inclination ROM 108 and an intercept ROM 109 storing inclinations and intercepts of the respective approximation straight lines, an address computing means 112 computing addresses of the inclination ROM and the intercept ROM, a multiplication apparatus 110 performing multiplication between the output value and the input value of the inclination ROM, and an adder 111 performing addition of the output of the multiplication apparatus and the output of the intercept ROM. The address computing means 112 is a circuit sequentially carrying out determination on the input value step by step through a plurality of steps. The respective steps are configured of first-third ROM 105-107 storing criteria in addresses of the second power number and first-fourth comparators 101-104 comparing dimension of the criteria stored in the ROM with that of an input value for outputting a ROM address of the following step according to the comparison result. COPYRIGHT: (C)2005,JPO&NCIPI
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