| 摘要 |
<p>PURPOSE:To widely shorten the time of retrieval by using a tape traveling time obtained from the number of rotation of a reel, to which a magnetic tape is wound, for the high speed retrieval of arbitrary program information recorded on the magnetic tape. CONSTITUTION:A reel pulse to be generated by the rotation of a winding reel 3 is detected by a detector 18 and the number of rotation is computed by a measuring circuit 19 and supplied to a tape traveling time arithmetic circuit 20. Then, in the circuit 20, the traveling time of a tape 1 is calculated based on a counted value and outputted to a control part 13. In the control part 13, the present position of the magnetic tape 1 is calculated based on the traveling time information and difference to a purpose position is obtained. When the difference goes over a setting value (d), whether the purpose position is in front or back of the present position is compared 11 and super-high speed retrieval is continued. Then, the retrieval is continued until the difference goes into the setting value (d). When the difference goes into the setting value (d), the retrieval of the present position of the tape 1 is obtained by the rotational number of the reel 3 without reading a sub code which is recording to the tape 1.</p> |
