| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem of heat generation and to amplify an optional waveform with a low distortion factor even when the level of a transmission signal is varied. SOLUTION: An ultrasonic diagnostic apparatus is constituted so as to generate a pair of pedestal clamp pulses (bias pulses) Vb1 and Vb2 each having a pulse width corresponding to an original transmission signal and having a bipolar symmetric property by a pedestal clamp circuit (a bias setting circuit) 30. A pseudo-linear amplifier 32 sets a bias point according to levels of the pulses Vb1 and Vb2, and linearly amplifies the original transmission signal only in the period of the pulse. Also, a drive power source variably sets electrical potentials HV1 and HV2 of the drive power source, and the level of the transmission signal outputted from the pseudo-linear amplifier 32 is variably set. Furthermore, an operating point is kept at a prescribed value by the levels of the pedestal clamp pulses Vb1 and Vb2. COPYRIGHT: (C)2004,JPO
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