| 摘要 |
PROBLEM TO BE SOLVED: To generate a transmission signal which exhibits similar characteristics to a high-voltage single pulse by a transmission circuit which is not adapted to high voltage in an ultrasonic diagnostic system. SOLUTION: The transmission signal 34 corresponds to a composite waveform which is composed of a trapezoidal waveform 30 and a reverse impulse waveform 32. In the transmission signal 34, a slope part 34A, flat parts 34B and 34D and a slope part 34E exist on the side of the positive electrode 36. The impulse part 34C has a shape protruding from the offset level and crossing the base line toward the other polarity. It is possible that the slope part is provided for only one side of the impulse part 34C and a pulse part is provided for the other side. The center frequency of the trapezoidal waveform 30 exists near DC and can be substantially ignored. Since the impulse part 34C straddles both polarities, it is not necessary to respond to the high voltage at both polarities. It is possible to add a trapezoidal waveform of the reverse polarity preceding the trapezoidal waveform 30. COPYRIGHT: (C)2008,JPO&INPIT
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