| 摘要 |
<p>PURPOSE:To make fast a lead-in time of a tracking and to reduce the variance by detecting a beat signal component outputted when the relation of the frequencies of local pilot signals is that they are adjacent alternately and shifting the local pilot signal for two fields. CONSTITUTION:At a time of a rise of a capstan motor, when frequencies of a pilot signal of a running track on which the first and the second rotating magnetic heads 2, 3, are running and a local pilot signal have the relation that they are adjacent alternately on a track pattern, a component of a frequency 2XfH or 4XfH are included in a beat component. The component of this frequency 2XfH or 4XfH is taken out by a B.P.F32 or a B.P.F33; this signal is inputted to a level detecting circuit 34 to detect whether more than a fixed level of the bear signal component of the frequency of 2XfH, 4XfH is present or not and discriminate. In a pilot signal generator 12, the local pilot signal is shifted for two fields by this shift signal.</p> |
