| 摘要 |
PURPOSE: To reduce cost by enabling a meter to have an oscillator that is set to an operating frequency that is equal to or higher than 50MHz and incorporating a level response part for modifying a phase state for determining the oscillation of the oscillator when a preset limit value is exceeded. CONSTITUTION: A meter 2 includes a dipole 5 for connecting an oscillator 6 that is set to an operating frequency of 50MHz or higher. Also, the oscillator 6 is connected to a proper evaluation device 8 by a line 7. Then, the dipole 5 is adjusted to the oscillation frequency of the oscillator 6. When a level is above a line 4, namely above the dipole 5, the dipole 5 discharges energy into a liquid and power is consumed, thus causing the output voltage of the back coupler of the oscillator 6 to decrease, preventing the amplitude conditions for determining the oscillation of the oscillator 6 from being satisfied, and causing the oscillator 6 to stop oscillating. Also, when the level is below the line 4, the dipole 5 cannot discharge energy into the liquid so that no output voltage of the back coupler of the oscillator 6 decreases, thus satisfying amplitude conditions and causing the oscillator 6 to oscillate.
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