| 摘要 |
PROBLEM TO BE SOLVED: To generate a driving signal with a waveform of an intended frequency spectrum without using a linear amplifier. SOLUTION: In transmission circuits 21-1 to 21-n corresponding to a plurality of channels respectively, a waveform data output part 21a outputs waveform data indicating a basic signal having a same waveform in either of the transmission circuits 21-1 to 21-n. A random noise generation part 21c generates random noise (a random coefficient) having an amplitude smaller than the maximum amplitude value of the basic signal and having no relation to relative positions of a plurality of ultrasonic transducers. The waveform data is multiplied by the random noise by a multiplier along with an apodization factor output by an apodization factor output part 21b to be weighted according to the random noise. The weighted waveform data are converted into analog data by a D/A conversion part 21f to be output as the driving signal. COPYRIGHT: (C)2006,JPO&NCIPI
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