| 摘要 |
PURPOSE:To form recording tracks concentrically by providing a magnetic sheet with a reference track where a vertical synchronizing signal and a reference signal are recorded, and detecting the extent of eccentricity of the sheet by reproducing the signals on the reference track during recording. CONSTITUTION:The innermost track 2 of a magnetic sheet 1 is used as a reference track, where a vertical synchronizing signal and a reference signal containing a wobbling frequency component are recorded. In recording a video signal, the reference track 2 is scanned firstly to detect the vertical synchronizing signal, and the phase difference of the video signal from the vertical synchronizing signal and the extent of eccentricity of the sheet 1 are stored in a storage device 29. On the basis of the stored phase difference, the vertical synchronizing signal of the video signal is delayed and a driving power source 14 is controlled according to the extent of eccentricity to record the signal on a sheet 1 by a head 9 over rotary phase servocontrol over a driver 13. |
