| 摘要 |
<p>PURPOSE:To attain normally a tracking control by prohibiting the detecting of a sink signal when the level of the pilot signal frequency component in the output signal of respective rotating heads is not the prescribed relation to the level of the pilot signal of an on-track. CONSTITUTION:A sample holding S/H circuit 103 sample-holds the DC level of the pilot signal on one adjoining track by the timing of a sampling signal SP1 from a sink detecting circuit 202. An S/H circuit 105a supplies the DC level of an on track pilot signal during the reproduction of the A track of a +azimuth to the control input of a level adjusting circuit 109 and supplies it to one side input of a comparator 107. For the comparator 107, when the 1/2 of the level inputted through a switch SW2 is smaller than the input from an envelope detecting device 102, the output comes to be H, and an ATF window off signal is supplied through or gates 217 and 218 to the sink detecting circuit 202.</p> |
