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).
