| 摘要 |
PURPOSE:To omit a track exclusively used for tracking control and also receiving virtually no effects of the drop-out, the clogging of a magnetic head, etc., by dividing the tracks of a magnetic head for reproduction into two groups of different arrays and using the difference of outputs obtained from both track groups as a tracking control signal. CONSTITUTION:For tracks of a magnetic head for reproduction, tracks P1-P4 are shifted to the upper side from the center O of a magnetic tape with tracks P5-P8 shifted to the lower side from the center O respectively. The reproduction outputs S1-S8 of tracks P1-P8 are amplified by amplifiers 1-8 and then delivers as outputs S1'-S8' after the adjustment of variance carried out by attenuators 9-16. The outputs S1-S4' given from attenuators 9-12 are used as the 1st signal f1; while the outputs S5-S8' of attenuators 13-16 are used as the 2nd signal f2. Both signals f1 and f2 are calculated by a differential amplifier 29 for production of a control signal Cs. In such a way, no track is needed exclusively for tracking control. Furthermore the tracking control is made possible without effect of drop-out of the magnetic tape. |
