| 摘要 |
<p>PURPOSE:To automatically adjust a switching point for a video head changeover at the time of an adjustment mode. CONSTITUTION:The adjustment mode is set by a microcomputer 21 with a pilot signal inputted during a horizontal blanking period of a video signal from a video signal processing circuit 6. Then, a control ant. is calculated by the microcomputer for the purpose of setting a space between a vertical synchronizing signal and a video head changeover signal for 6.5H. The video head changeover signal is generated in timing corresponding to this control amt. by a servo circuit 8 based on a position detecting signal of a rotary drum 11. and hence a head changeover switch 5 is changed so as to select a video head 2a or 2b. Consequently, a circuit configuration is simplified at low cost, and moreover, durability is superior.</p> |
