| 摘要 |
PURPOSE:To improve the variable power accuracy by determining an output frequency of a reference clock generator so that a fraction under a decimal point is not generated in a result of operation of a variable power of an operation controlling circuit in accordance with the minimum resolution. CONSTITUTION:When an output frequency of a reference clock generator 32 is set so as to become E for satisfying an expression: E=100Xn (n is an integer), an arithmetic controlling circuit 33 receives a variable power M(%), derives a necessary clock number E' by executing a calculation determined by an expression: E'=EX(M/100)=100nX(M/100)=nM, and a stepping motor 31 receives a driving pulse P=F/E' (F is a frequency of a reference clock) from the arithmetic controlling circuit 33 and drives a driving transfer mechanism 34. Since E' is an integer, there is no excess nor short in an input pulse rate to the motor 31, and an optical system 20 can always be moved at a correct speed. |
