LASER LENGTH MEASURING DEVICE

PURPOSE:To measure the distance with high resolution corresponding to speed all the time, by changing the constant of a frequency multiplier in response to the change in moving speed of a body, and inputting the constants to the frequency multiplier at an arbitrary timing. CONSTITUTION:A CPU21 is provided to issue a command, so that the optimum multiplying constant is stored in registers 15 and 16, based on the position data of the movable body 5 which is stored in a register 23 from an up and down counter 20 in response to the predicted change in the moving speed of the movable body 5 or in response to the request from comparators 26 and 27. An interface circuit 22 recives the command from the CPU21 and stores the optimum multiplying constants m and n to the registers 15 and 16 at an arbitrary timing. The constants for frequency multiplier 11 and 12 and frequency divider 13 and 14 are changed, respectively.