| 摘要 |
PURPOSE:To eliminate a reel rotation period measured value exceeding an allowable range, by deciding the stability of rotation of a reel, and a measured rotation period error range, by a rotation period difference of the reel of every rotation of a continuous prescribed number, and inspecting the validity. CONSTITUTION:A rotation period of one reel 3 is measured by a slit disk 9, an interval timer 11, etc. which are turned as one body with the reel 3, and a measured rotation period difference against the time of rotation immediately before every continous three rotation is calculated through storage circuits 14, 15 and subtraction circuits 16, 17. When a difference of these difference values becomes below a set value, a reel rise stability deciding output is generated from a comparing circuit 18 and is applied to an AND gate 20. In this state, in accordance with a measured rotation period of continuous two times of the other reel 2, a comparing circuit 13 applies a deciding output as to whether the measured rotation period error is below a prescribed value or not, to a gate 20. A tape position operation circuit 21 for calculating a tape position from a rotation period ratio of the reels 2, 3 is controlled by this gate 20, and evaluation which is capable of elmininating a measured value of an error exceeding an allowable value is executed. |
