| 摘要 |
An ultrasound wave is transmitted from a probe ( 120 ) to a moving reflector ( 130 ) and the reflected ultrasound wave is received back by the same probe ( 120 ). With n-divided wave bands of the to-be-used spectrum, the ultrasound wave to be transmitted is made up of up chirp signals and down chirp signals from n number of down chirp signal generators ( 112, 113 ) and up chirp signal generators ( 116, 117 ), creating complementary multiplexed chirp signals through synthesizers ( 114, 118 ). Cross-correlation is taken by a correlator between the reception signal received at the probe ( 120 ) and the up chirp and the down chirp signals, respectively, so as to provide compressed up and down signals and then combining the obtained compressed signals through synthesizers ( 144, 148 ). Doppler measurement is performed by determining the correlation distance through taking the cross-correlation between these compressed signals by a cross-correlator ( 160 ) and performing envelope detection by an envelope detector ( 170 ).
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