| 摘要 |
PURPOSE:To improve resolution by calculating the position of a measurement point from a specific proportional arithmetic expression based upon two signal values selected in an interpolation section divided by zero points of plural signal in the interpolation section. CONSTITUTION:A processing circuit consists of a measurement part 10, a correction part 20 having subtracters SB1-SB4, a multiplier MP1, a divider DV1, etc., an interpolation part 40 having subtracters SB6 and SB7, a divider DV2, etc., a control part CTL, etc. Then, the resolution is improved greatly by calculating the position of the measurement point P in the interpolation section divided by points a0 and b0 where signals (a) and (b) generated by an encoder detection part become zero from an equation l=[Xp/(Xp-Yp)]alpha, (where l is the movement extent of the measurement point P, Xp and Yp are values of the two signals at the measurement point P, and alpha is the position shift extent of an encoder which indicates the length of the interpolation section). |
