| 摘要 |
PURPOSE:To improve productivity, by grounding one pont of a loop conductor constituting a coupling circuit by a capacitor and varying the coupling quantity to obtain an electric signal having a high S/N. CONSTITUTION:When the electrostatic capacity value of a capacitor 21 connected between a halfway position of a loop conductor 20 of a coupling circuit 2 and a partition plate 13 is changed, the resonance frequency of the coupling circuit 2 is changed, and the impedance of the coupling circuit 2 to a fixed frequency is changed, and therefore, the coupling quantity due to the coupling circuit 2 is adjusted. Consequently, a loop conductor which is formed on a substrate 15 by adhesion can be used as the loop conductor 20, and the coupling quantity is adjusted in accordance with types of a load of a fixed frequency oscillator and a used reproducing stylus to output easily the electric signal having a high S/N. |
