| 摘要 |
<p>PURPOSE:To attain quickly the edition of a tape and program search of prescribed information, by detecting a tape residual amount converted by a constant speed tape running speed at recording and reproduction, in an operating state where the magnetic tape running speed such as fast feeding and rewinding is changed timewise. CONSTITUTION:When a prescribed amount of magnetic tape is wound on a supply tape reel 1 and a rotating period of the supply tape reel 1 is Tr in running the tape at a tape running speed V at recording/reproduction, a tape residual amount (t) is obtained by measuring the data N of the number of revolution from the relation of t=v.(Tr+ or -N/2a)<2>/4pid-piD0<2>/4vd with the number of revolution N of the supply reel, where D0 is a diameter of reel hub and d is a thickness of a magnetic tape. In this case, the tape residual amount converted into the tape running speed at recording/reproduction is detected by having only to give the revolution period at tape running start point and the succeeding data of the number of revolution.</p> |
