| 摘要 |
PURPOSE:To shorten the time for operation and reduce operation error by obtaining trigonometric functions by an angle computer that represents angles of o deg.-360 deg. by 16 bits, data stored in a ROM after dividing a cosine curve from 0 deg.-90 deg. into 64 uniformly, and a formula to obtain a straight line from the data. CONSTITUTION:A straight line AB that approximates to CD which is 1/64 of a cosine curve from 0 deg.-90 deg. is drawn and an intersection Bn of the straight line AB and (y) axis OC and inclination (y'/x')=An are found out. Then, an intersection Bn and inclination An are found out for an approximate straight line A' B' between DE making (y) axis FD. Thus, the cosine curve from o deg.-90 deg. is divided into 64 by shifting (y) axis by 1/64, and An and Bn are found for all cases and stored in a ROM. It is examined which An, Bn data are to be cited from angle data converted to 16 bits according to a format, and values are substituted in a formula for finding a straight line Y=AnXX+Bn making lower 8 bits X, and the value of trigonometric function is obtained by the result of calculation Y. |
