| 摘要 |
PURPOSE:To obtain a reproduced FM signal having a sufficient level without being influenced by a change in the lapse of time, an adjustment variance, the warp of a disk or the like by making a relative distance between a signal sensor electrode and a disk signal surface variable according to the reproduced FM signal level. CONSTITUTION:When a voltage (a) that the reproduced FM signal, obtained from the disk 19 is converted into a DC level, is lower than a reference voltage (higher than a reference voltage), previously set in a window comparator amplifier 9, the output of a positive polarity (negative polarity) is fetched from the window comparator amplifier 9, and a carrier is raised (lowered) by a carrier height shifting motor 12, and the sensor electrode 2 of a sensor 20 is brought close to (away from) the disk signal surface 4. Thus, even if the sensor electrode 2 is worn by the time aging or the like, the reproduced FM signal with the sufficient level can be obtained, and further, even if the warp or the like exists at the disk 19, the reproduced FM signal with the adequate level can be obtained, and therefore, a turn table 18 can be miniaturized.
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