| 摘要 |
PURPOSE:To ensure the automatic switching of a bias equalizer, by forming the opaque stripes having a length equivalent to the type of the tape at the leader tape part and reading the length of the stripe while the tape is travelling. CONSTITUTION:In the recording/reproducing mode, a light emitting diode 4 glows. When the opaque stripe part passes the front of the diode 4, the pulses proportional to stripes (k) and (l) are obtained at the output of a phototransistor 5. When the pulse is delivered, an AND circuit 7 is opened to count the number of clocks. A pulse Q4 is delivered after the clock pulses are counted by the reference signal (k). Then a counter 9 is reset and a 1-shot circuit 10 is triggered to obtain a signal Q5. While the signal Q5 is delivered, the number of clock pulses equivalent to the stripes (l) is counted. In such way, the bias equalizer characteristics is automatically switched in accordance with the type of the tape. |
