| 摘要 |
<p>PURPOSE:To always detect the shift of a pickup or a magnetic head to the track width with the same type of frequency by avoiding that the two types of frequencies indicating the direction of said shift do not alter with every trace of the track. CONSTITUTION:A reference clock pulse delivered from an oscillating circuit 91 is applied to a frequency dividing circuit 92, and the circuit 92 divides the clock pulse to deliver four types of pilot signals f1-f4 individually in the form of rectangular waves. These pilot signals are applied to a switch circuit 93, and the circuit 93 selects and delivers one of signals f1-f4 by selection control signals Q1-Q4 supplied from a switch control circuit 95. This selected pilot signal is applied to a waveform converter 94 and delivered to a terminal 96. The signals Q1-Q4 are controlled when they are supplied so that the prescribed different orders are set for these signals in response to the mode. At the same time, the switch timing is controlled to obtain the coincidence between both modes.</p> |
