| 摘要 |
PROBLEM TO BE SOLVED: To prevent noise due to a power supply voltage from being mixed in a blood flow velocity pattern displayed on a screen by a switching frequency and a resonance frequency when using a resonance circuit. SOLUTION: In the power device of a pulse doppler ultrasonic diagnostic device for repeatedly transmitting ultrasonic pulses by a PRF, sampling reception signals in synchronism with the PRF and detecting a doppler shift frequency which is a difference between the transmission frequency and reception frequency of ultrasonic waves, control is performed such that the positive integral multiple of the switching frequency fd of a switching circuit 12 and the positive integral multiple of the resonance frequency fr of the resonance circuit 13 are outside the shift region of the doppler shift frequency fe. COPYRIGHT: (C)2007,JPO&INPIT
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