| 摘要 |
<p>PURPOSE:To detect the moving extent of a tape with a simple constitution even when no CTL signal is recorded by providing a fixed head having the head gap of a slope corresponding to the magnetization pattern of a track and detecting a track crossing the fixed head in response to the tape running. CONSTITUTION:A fixed head FH having a gap G in the same direction as the magnetization pattern of a track TA among tracks TA, TB recorded by heads A, B is provided to the transverse center of a tape T. The head FH crosses the track TA at a period T1 and moves gradually to the track TB, then the output of the hand FH is gradually smaller in the amplitude at the left side of the period T1 toward the right side. On the other hand, an inverted output is obtained at a period T2. This signal is compared with a threshold level via an amplifier, a detection circuit and a waveform shaping circuit and an obtained pulse is counted to detect the moving extent of the tape.</p> |
