| 摘要 |
PURPOSE:To switch the resonance state of a parallel circuit of resistance and inductance and enable the resonance of only an input signal by changing the impedance or resistance value of a diode every time when an output signal having a large amplitude and an input signal having a small amplitude are supplied to a cable. CONSTITUTION:When a L-level is output from a pulse generating circuit 4, a diode D0 is biased in the reverse direction by applying a high voltage pulse to the diode D0, and the impedance is made endless. A state in which a bias resistance Rb is connected in series to an inductance L0 is formed, and the current sent into the inductance L0 is limited by Rb to reduce Q-(=omegaL0/Rb), resulting in an elimination of the resonance effect. When an input signal is applied to a cable 2 from a vibrator 1 in the state in which a H level is outputted from the pulse generating circuit 4, the diode D0 is turned on while maintaining the forward directional bias, and thus the current sent into the inductance L0 is not limited to increase the value Q, resulting in the formation of the resonance state. |
