| 摘要 |
PROBLEM TO BE SOLVED: To solve such a problem that a quantum error increases for a whole amplitude after D/A conversion when adjusting the amplitude of a digital waveform signal in a digital waveform generator, in an ultrasonograph. SOLUTION: An attenuater 22 is disposed in the rear step of a D/A converter 14, and the amplitude is suppressed by the attenuater 22. Namely, the digital waveform signal having a maximum amplitude is outputted from the digital waveform signal generator 20, it is made to an analog waveform signal by D/A conversion, and the amplitude is suppressed in the attenuater 22 for the analog waveform signal. The degree of the suppression of the signal in the attenuater 22 can be switched stepwise or continuously. COPYRIGHT: (C)2003,JPO
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