| 摘要 |
A video disc playback system consists of a stylus having the first, the second and the third electrodes which are located on different side of the stylus and detecting signal varied with capacitance of the contacted surface of disc, the first, the second and the third detectors converting variation of capacitance to output signal, a microprocessor for demodulating video and audio signal which is connected to the signal detector, a comparator generating signal which is compared output signal of the detector with reference signal and a tracking device connected to the output of comparator to control position of the stylus.
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