| 摘要 |
<p>PURPOSE: To achieve a saving of power for an ATF circuit. CONSTITUTION: Reproduction signals which are obtained by reproducing a tape 1 having pilot signals with frequencies f1 and f2 recorded thereon by rotary heads 2a and 2b are applied to a digital ATF circuit 6 to extract f1 and f2 with BPFs 7a and 7b. The frequency components are detected separately to be converted to level signals, which are averaged using LPFs 9a and 9b and fetched into a control section 11 to determine a level difference. As result, an ATF error signal is generated indicating an off track value. A PLL circuit 13 outputs a clock CL locked in phase to the reproduction signals to be supplied to the ATF circuit 6 through a switch 14. The control section 1 turns OFF the switch 14 while the AFT circuit 6 is not required to extract the f1 and f2 to stop the operation of the ATF circuit 6 thereby enabling reducing of useless power consumption.</p> |
