| 摘要 |
PURPOSE:To enable to obtain good picture quality even when reproducing at varied speed by wrapping a head with a wrapping tape while oscillating a bimorph to attenuate slowly. CONSTITUTION:A period in which a magnetic head traces one track on a tape (at the time of high level of pulse wave, that is, t1, t2...t3) is bisected into the first half and the second half. In the first period t1 of tracing, positive.negative voltage +V1, -V1 equal to positive.negative voltage +V0, -V0 in which absolute value of titled voltage is maximum or larger than +V0, -V0 are supplied to a bimorph in the first half and second half respectively. In the next period t2 of tracing, negative.positive voltage -V2, +V2 obtained by subtracting about 25% of absolute value from negative.positive voltage -V1, +V1 are supplied to the bimorph in the first half and second half. In the next period t3, voltage is reduced by 50%, and reduced by 75% in the period t4, and in the period t5, voltage is not supplied entirely, i.e. made to the state of zero V. Thus, wrapping tape is traced by the magnetic head while supplying voltage to the bimorph. |
