| 摘要 |
PURPOSE:To perform the tracking control of two sets of rotary heads without using an inverter by using the frequency signal and the pilot signal of the next but on adjacent track as the standard of comparison with the pilot signal of the adjacent track. CONSTITUTION:The frequencies f1-f4 of pilot signals which are cyclically recorded for each track are defined as (f1-f2)=(f3-f3)=alpha and (f2-f3)=(f4 -f1)=beta. For instance, a head 2a corresponds to a track T2 of a pilot signal of frequency f1, and therefore a signal of frequency f1 is selected by a switch 12 among signals of frequencies f1-f4 and applied to a mixer 14 as the standard of comparison with the signal of the adjacent track. A track error signal is delivered from an amplifier 19 which processes signals alpha and beta. When an adjacent track T3 is tracked by a head 2b, the reference signal which is selected by the switch 12 via switches 23-26 has successively frequencies f1, f4, f3 and f2 respectively. Then the reference signal corresponds to the frequency f4 of the pilot signal of the next but one adjacent track T5, and the error signal has no inversion. Thus no inverter is needed. |
