| 摘要 |
<p>PURPOSE:To display the remaining quantity time of a tape with high accuracy, by estimating the difference between the present and the preceding rotational period of a supplying reel with a statistical method, and calculating the remaining quantity time of the tape based on an estimated value. CONSTITUTION:A magnetic tape 2 supplied from the supplying reel 1, after being scanned slidably by a head 4 via a guide pole 3, is taken up by a take-up reel 8 passing between a capstan 5 and a pinch roller 6 and via a guide pole 7. A rotation detector 9 constituted of a magnetic sensor, etc., for example, generates a pulse corresponding to the rotation of the supplying reel 1, and outputs it to a rotation detecting part 10. After the difference (d) of the rotational period at every rotation of the supplying reel 1 is calculated with the statistical method based on the rotation speed N and the rotational period T of the reel 1 detected by the rotating detecting means 10, the remaining quantity time of the tape is calculated at an arithmetic circuit 11 by equation I, and is displayed on a display unit 12. Also, it is assumed that RH shows the diameter of a reel hub, and V shows the traveling speed of the magnetic tape 2.</p> |
