| 摘要 |
<p>PURPOSE:To obtain a tracking error signal with simple constitution by recording pilot signals, differing in frequency, on a video signal frame by frame alternately, and by comparing the level of the beat signal of their reproduced signals with a reference voltage. CONSTITUTION:A 3.58MHz signal is supplied to terminal, and pilot signals with frequencies f1 and f2 are supplied to a switch SW1 through frequency dividers 18 and 19. The switch SW1 is changed over in every half period through an FF21 receiving a head switch signal through a terminal 20. The pilot signals are passed through a BPF22 and synthesized with a color signal 23 passed through an HPF24 and an Y-FM signal 25 to generate an output 26. A color signal 27 is supplied to a BPF28, a detecting circuit 31, and a BPF23 to extract the beat signal of the pilot signals, which is passed through a detecting circuit 33 and a gate circuit 35 to obtain a signal during the contact period of a head. The output is compared by a comparator 37 to input its difference signal to a driving circuit 39. Thus, a tracking error signal is obtained by the simple constitution.</p> |
