| 摘要 |
PURPOSE:To shorten the pull-in time of phase locked by switching the reference potential of an amplifier to a potential different from that in steady operation for a specific period in mode switching between normal reproduction and special reproduction and shifting a phase error signal in level. CONSTITUTION:The reference potential selected by a reference potential switching circuit 11 is E0 in a steady state of normal reproduction and special reproduction, E1 for the constant period when the normal reproduction is switched to the special reproduction, and E2 for the constant period when the special reproduction is switched to the special reproduction. The level shift quantity of the reference potential of the amplifier 10 when the normal reproduction mode is switched to the special reproduction mode or vice versa and the length of the times when the reference potential is switched from E0 to E1 or E2 are selected properly. Consequently, the pull-in time of phase locked required for the mode switching is shortened.
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