| 摘要 |
PURPOSE:To realize an automatic control for the proper playback amplification gain although a local defect may occur to the AGC region, by having a retrial through an automatic shift of the detector in case when some error arises to the reference signal caused through detection of the AGC region of the magnetic recording medium having the oblique and parallel tracks. CONSTITUTION:The prescribed playback level control is carried out through the detection of the AGC region 2 of the magnetic tape 1 having the oblique and parallel tracks 3 before the recording and playback and then an automatic control given to the gain of the playback amplifier 15 via the AGC circuit 16 and in accordance with the playback reference signal. In case when the local defect 21 exists at the strip 221 of the region 2 and the circuit 16 detects the error when the region 2 is detected, the tape 1 is shifted by a prescribed extent via the driving circuit 17 and the motor 18. And then the retrial detection is carried out through the strip 222. As a result, an automatic control is secured for the playback amplifier to obtain the proper playback gain althrough the local defect may arise in the AGC region due to the abrasion, the sticking of dust and the like factors. |
