Ultrasonic Doppler Blood Flow Meter

1 . An ultrasonic Doppler blood flow meter, comprising:

a transmitter for generating electric pulses;

a probe for receiving the electric pulses and transforming the electric pulses, the probe transmitting the transformed electric pulses into a body or subject to be tested and then receiving a signal including an echo signal responsive to the electric pulses from the body;

a phase detector for phase-detecting the echo signal from the signal received by the probe;

a wall filter for eliminating a low frequency clutter component from the echo signal detected by the phase detector;

a blood flow data calculating unit for calculating blood flow data from an output in which the low frequency clutter component has been eliminated;

a digital scan converter for transforming the blood flow data from the blood flow data calculating unit into another form of signal; and

a monitor for using the another form of signal to display blood flow data;

characterized in that

the ultrasonic Doppler blood flow meter further comprises

a clutter component estimation unit for approximating the clutter component by a sinusoidal wave by using at least two signals from the phase detector;

an initial filter value generating unit for generating initial values of the wall filter by using the sinusoidal wave approximated by the clutter component estimation unit;

a cutoff frequency setting unit for setting a cutoff frequency of the wall filter from the estimated clutter component; and

a clutter differentiating unit whether an amplitude of the estimated clutter component indicates the clutter component or the blood flow data from the amplitude information in a region adjacent to another region where it is under scanning or the amplitude information of the clutter component obtained by a previous scanning of the same region.

2 - 4 . (canceled)