| 摘要 |
A pickup appts. for use in video playback system of a type involving variation of a stylusdisc capacitance in accordance with recorded information, comprised a source of oscillations at a nominal frequency in the vicinity of the given range of frequencies, device for supplying oscillations from the source to the tuned cct. and amplitude detector coupled with the tuned cct. The conductive stylus support arm is with a length more than a quarter-wavelength and less than a half-wavelength at the oscillation frequency and the frequencies within the given range.
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