| 摘要 |
<p>PURPOSE:To easily correct the head tracking deviation for reproducing with a button operation by varying the pulse width of a pulse width modulation signal to control the charging current of the time constant capacitor of a time constant circuit and variably setting the time constant of a monostable multivibrator. CONSTITUTION:A time constant circuit 31 of the monostable multivibrator is provided with one switching element Q which switches the charging current of a time constant capacitor Cy by the pulse width modulation signal to vary the time constant in proportion to the pulse width. The turning-on period and the turning-off period of the switching element Q are varied by varying the pulse width of the pulse width modulation signal to variably control the charging current of the time constant capacity Cy, thereby variably setting the time constant of the monostable. multivibrator. Thus, the tracking deviation is easily corrected by the button operation.</p> |
