| 摘要 |
<P>PROBLEM TO BE SOLVED: To increase accuracy of extracting Doppler information in extracting the Doppler information from a target position by using continuous waves. Ž<P>SOLUTION: An FM modulator 24 performs frequency modulation processing on a first modulation wave by using a second modulation wave as a modulation signal. An FM modulator 20 performs frequency modulation processing on an RF wave by using the first modulation wave that is modulated as a modulation signal. A reference signal supplied to a reception mixer 30 is generated from an FM continuous wave which is doubly modulated and is output from the FM modulator 20. Delay processing is performed on the reference signal in a delay circuit 35 in accordance with a depth of the target position in a living body, and a Doppler advantageous signal which is advantageous for extracting a Doppler signal is extracted in the reception mixer 30. The reference signal supplied to a reception mixer 40 is generated from the first modulation wave output from the FM modulator 24. Delay processing is performed on the reference signal in a delay circuit 45 in accordance with the depth of the target position in the living body, and the Doppler advantageous signal from the target position is selectively extracted in the reception mixer 40. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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