| 摘要 |
PURPOSE:To shorten considerably a calculation time required for phase compensation while maintaining necessary phase compensation precision by using a phase compensation error estimating device and an automatic setter for the number of divisions in combination. CONSTITUTION:The device is provided with a range calculating device 20, reference coordinate setter 21, phase calculating device 22, interpolator 25, phase compensation error estimating device 27, automatic setter 28 for the number of divisions, etc. Then the setter 28 sets L=2 and K=128, where N is an integral number, L is the number of divisions, and N/L is K; and the calculating device 20 calculates L+1=3 phases per gate at relative distance. The result is inputted to the estimating device 27 to estimate a phase compensa tion error. At this time, when the error is within a permissible range, the output of the calculating device 22 is inputted to the interpolator 25 and phase compen sation is completed. When, however, the error is not within the permissible range, L=4 and K=64; and the phase calculation is performed again. At this time, five distances and phases per gate are need not be calculated again. Here, a phase compensation error is estimated from the five phases. |
