| 摘要 |
<p>PURPOSE:To prevent a BOT marker for a magnetic tape from an error by detecting the marker once and stopping the magnetic tape to detect the BOT marker again in the stopped state, and if the BOT marker is not detected, by travelling the magnetic tape slightly to detect the BOT marker again. CONSTITUTION:When the BOT marker is detected and the magnetic tape is stopped, the BOT marker 1 is detected again at that time t2. When the magnetic tape is detected again, the detection is regarded as normal status and the detecting operation is completed. If reflected light is not detected because of a fold or dirt, a capstan motor is driven again and the magnetic tape is travelled by about 0.8mm. e.g. and then stopped. The BOT marker is detected again at time t3, and if detected, the detection is regarded as normal state. If the BOT marker is not detected, the tape is travelled slightly moreover and the marker is detected at t4. When the BOT marker is not detected even if redetection is repeated several times, an error signal is generated for the first time.</p> |
