| 摘要 |
PROBLEM TO BE SOLVED: To obtain a sine/cosine arithmetic circuit that does not need a large capacity memory for previously writing operation results by using specific operation results and obtaining the operation results in quadrants other than a prescribed and limited quadrant. SOLUTION: An absolute value/code extraction circuit finds an absolute value signal |A| of a phase angle signal A being an input signal and a code information signal IS, and a sine/cosine approximation arithmetic circuit finds sine operation results S and cosine operation results C in a 1st quadrant through a primary approximation operation shown by an expression in accordance with a low order (N-2) bit of the absolute value signal |A|. A phase rotation processing circuit performs phase rotation processing by replacing the results S and C obtained by performing the approximation operation in accordance with the signal of three bits of high orders of the signal |A| and inverting a code and obtains sine operation results SIN and cosine operation results COS in the quadrants other than the 1st quadrant by that. In this expression, Kij and Lij are each 0 or ±1, Mi and Ni are each 0 or 1 and zero (ω) is 0 in the case of ω=0 and is 1 in the case of ω≠0. |
