| 摘要 |
PURPOSE:To correct tracking automatically by slantingly fixing a tracking detecting head of track width greater than that of a reproducing head to the reproducing head and by detecting as a tracking differential signal a phase shift between reproduced signals of both the heads. CONSTITUTION:A tracking detecting head with track width greater than that of a reproducing head is fixed to the reproducing head slantingly. The reproduction output of reproducing head 2 is passed through voltage amplifier 13 to obtain reproduced signal 15, which is also inputted to mixers 20 and 21 via LPD14. The reproduction output of detecting head 4 is inputted to mixers 20 and 21 via voltage amplifier 16, phase inverter 17, and delay devices 18 and 19. Both delay devices 18 and 19 differ in delay time. The output of mixer 20 is inputted to mixer 25 via wave detector 22 and inverter 23, and the output of mixer 21 is inputted to mixer 25 via wave detector 24. The output of mixer 25 is passed through current amplifier 26, switch circuit 27 and DM motor 9 to correct tracking automatically. |
