| 摘要 |
PURPOSE:To feed a video head from a prescribed track by an optional number of tracks by recording successively and repetitively three tracking signals having the 1st-3rd frequencies with an equal amplitude and calculating the differences among these three tracking signals. CONSTITUTION:The tracking signals f1-f3 reproduced by a video head 1 are amplified by an amplifier 2. This amplifier 2 operates only in a vertical flyback time of a video signal by a gate pulse (g). These amplified tracking signals are separated from each other through a BPF1 which transmits only the signal f1, etc. An operator F1 calculates (f1-f2), and this calculated value is amplified and cut with the positive/negative threshold values to deliver arithmetic signals F (1,2) of trapezoidal waves. The terminals (a)-(c) of a rotary switch SW are connected to operators F1-F3 respectively. At the same time, a rotary contact (d) is turned clockwise or counterclockwise by a command of a controller 3. |
