| 摘要 |
An information playback system, for recovering information recorded on a record medium, includes a pickup stylus having a conductive element establishing a capacitance with the record medium that varies with the recorded information, a conductive support housing, and a flexibly mounted conductive member supporting the pickup stylus and forming a transmission line with the surrounding support housing. The flexibly mounted conductive member has one end movably connected to the support housing and the second end mechanically coupled to the stylus to provide mechanical support therefor. An electrical connection is provided between the flexibly mounted conductive member and the conductive element of the stylus to establish a tuned circuit including the reactances of the transmission line and of the variable capacitance formed between the stylus and the record medium. A source of signal energy coupled to the tuned circuit energizes the tuned circuit such that signals modulated by the record information are developed in the tuned circuit. When the stylus is in playing position, capacitance between the support housing and the record medium is established with sufficient magnitude to provide a low impedance path for the modulated signals between the record medium and the support housing, completing the tuned circuit connections in a manner advantageous to pickup sensitivity. |
