| 摘要 |
PURPOSE:To reduce the unnecessary radiation of a constant-frequency signal, by applying the output signal obtained from a resonator through inductive coupling to a detector after the amplification of an amplifier and thus obtaining reproduced information, and decreasing the level of the constant-frequency oscillation signal energized to the resonator by the level corresponding to the gain of the amplifier. CONSTITUTION:A reproducing stylus 1 having an electrode part 1 scans on recording tracks on a recording medium disk 2 where an information signal is recorded in the form of an array of bits to detect and reproduce the information signal as variation in electrostatic capacity; and the resonance frequency of the resonator 4 coupled with the reproducing stylus 1 is varied and the output signal obtained from the resonator 4 through the inductive coupling 6 is amplified by the amplifier 9 and then inputted to the detector 7. Thus, the level of the constant-frequency oscillation signal energized from an oscillator 3 to the resonator 4 through inductive coupling 5 is decreased, so the unnecessary radiation of the constant-frequency oscillation signal generated of an open part of the resonator 4 where sealing is not done sufficiently. |
