| 摘要 |
<p>PURPOSE:To preform a tracking in a simple and accurate way, by recording also the pilot signals of prescribed frequencies which are different with every prescribed period and then reproducing those pilot signals as the crosstalk from the adjacent tracks to detect a shift of tracks. CONSTITUTION:The pulse signals that are formed through a horizontal synchronous signal dividing circuit 3 plus dividers 5-8 with the repetitive frequencies equivalent to 1/2, 1/3, 1/5, 1/7, and the like of the horizontal scan frequency give a control to a gate circuit 10 via a switch 9 which is switched with every track forming period. The horizontal blanking period signals produced through a voltage control oscillator 15, a 1/16 divider 12, an LPF18, an FF13, a gate circuit 19 and others are applied to the circuit 10. Then the low frequency pilot signals of frequencies different with every track are also recorded in the horizontal blanking period via a mixer 20 and others. The pilot signals of the adjacent tracks are reproduced as the crosstalk to detect the shift of tracks in accordance with the difference of levels. Accordingly even a large track shift can be detected accurately without impairing the picture quality. Thus a simple and accurate tracking is possible.</p> |
