SINE-WAVE AMPLITUDE VALUE GENERATING DEVICE

摘要

PROBLEM TO BE SOLVED: To effectively decrease the necessary storage capacity by selecting a case wherein the value obtained by reading a value stored by subtracting a phase address from a sine amplitude value and adding the phase address is outputted as it is or a case wherein the sign is inverted according to a quadrant decision result. SOLUTION: A storage means 4 is stored with the difference from the straight line connecting a sine-wave amplitude value (=0) whose phase is 0 and a sine- wave amplitude value (=1) whose phase is π/2 to each other. Representing the phase discretization number of a sine wave with a 1/4 cycle as N and the phase address determined by a phase address determining means 2 as (n), the value stored in the storage means 4 is sin π(n+0.5)/(2N)}-n/N. A normalizing means 5 normalize the phase address (n) determined by the phase address determining means 2 with the phase discretization number N, and an adding means 6 performs addition to the output from the storage means 4. Through this addition, sin π(n+0.5)/(2N)} is obtained.