| 摘要 |
In certain video disc systems it is desirable to have a stylus position sensing apparatus. An electrode secured in fixed relation to a movable stylus is disposed between first and second electrodes to form first and second variable capacitors therewith. The capacitance of the variable capacitors change relative to the motion of the stylus related electrode between the first and second electrodes. Complementary signals are applied to the first and second electrodes, which signals are coupled proportional to the respective variable capacitances to the stylus related electrode. The algebraic sum of the signals coupled to the stylus related electrode is indicative of the position of the stylus.
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