| 摘要 |
PURPOSE:To correct a shift in track with high precision by constituting a rotating- angle control system of a magnetic-tape feeding motor in a continuous closed loop by using its rotating-angle detector and a track shift detecting circuit and rotating- angle detector at a head rotor side. CONSTITUTION:On magnetic surface 15 of magnetic tape 2, signals for track-shift detection differing in frequency according to information tracks are recorded repeatedly by turns at the beginnings of information tracks. While the center between parts where frequencies are recorded is regarded as the center of the information track, this is reproduced via magnetic head 14 to separate respective frequencies by a filter and reproduction output levels of respective frequencies are compared, so that when reproduction output levels of respective frequencies are equal, the agreement between the scan track center of magnetic head 14 and the center of the information track will be detected. For this purpose, the reproduction output of magnetic head 14 is extracted through track-shaft detecting circuit 37 consisting of the filter and comparator, and consequently capstan motor 18 is driven by an angle equal to the track shift, so that the track shift will be corrected. |
