| 摘要 |
<p>PURPOSE:To facilitate digital control by detecting four pilot signals separately, amplifying each pilot signals by an automatic gain control amplifier, and utilizing the gain control signals as an error signal for controlling. CONSTITUTION:Pilot signals separated by band pass filters 2-5 are inputted to a switching circuit 6, and inputted to an amplifier 8 at time division by a switching pulse inputted from a digital servo 11, being a controller, and amplified. At this time, output of the amplifier 8 is operated to keep a fixed level just before saturation by a gain adjuster 9. That is, the amplifier 8 operates as an automatic gain control amplifier, and the gain adjuster 9 outputs the gain in a digital value as gain information. This is a value that corresponds to the level of each pilot signal, and can be utilized as an error signal of tracking control.</p> |
