| 摘要 |
PROBLEM TO BE SOLVED: To provide equipment for ultrasound operations that can vibrate a transducer with ultrasound easily even in a situation when a load impedance is high such as a case when holding a tissue with a hand piece. SOLUTION: Current Ipp detected at a current detecting part 15 and current set at an output setting part 17 are compared at a current comparing part 16 from starting to output till reaching the current level set in advance. After signals that represent the difference obtained at a current comparing part 16 receive a treatment to control the output, or multiplying a sine wave form a voltage controlled oscillator 19 at a multiplying circuit 18, the signals give a huge amount of energy to the transducer until the hand piece 2 begins to vibrate. Since the phase difference between voltage phase signals V and current phase signals I become detectable at a detecting circuit 11 once the impedance becomes lower and vibrations are made, the resonant frequency is tracked down by a phase-locked-loop control. After the output reached the level as it was set, the phase-locked-loop control controls to judge to see if a driving frequency remains within a certain frequency or not.
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