Ultrasonic blood velocity detector

Claim 2

An ultrasonic blood velocity detector comprising: an ultrasonic probe emitting ultrasonic waves into an examined body and converting echoes of the emitted ultrasonic waves into an echo signal; means for processing the echo signal into a detection signal through phase detection; means for deriving a first Doppler signal and a second Doppler signal from the detection signal, the first Doppler signal representing a flow of blood, the second Doppler signal mainly containing clutter components; and means for calculating a difference in phase between the first and second Doppler signals to detect blood velocity.

Claim 3

An ultrasonic blood velocity detector comprising: an ultrasonic probe emitting ultrasonic waves into an examined body and converting echoes of the emitted ultrasonic waves into an echo signal; means for generating trigger pulses at a predetermined period; means for generating a drive pulse signal synchronous with the trigger pulses; means for driving the ultrasonic probe by use of the drive pulse signal; means for generating a pair of reference signals orthogonal to each other; means for processing the echo signal into a pair of detection signals through orthogonal detection by use of the pair of the reference signals; means for integrating the pair of the detection signals for a first interval during which the echo signal represents a flow of blood within the examined body, and for converting the pair of the detection signals into a pair of first Doppler signals representing the flow of the blood, the first interval starting at a moment which follows each of the trigger pulses by a first predetermined time; means for integrating the pair of the detection signals for a second interval during which the echo signal represents a motion of an organ within the examined body, and for converting the pair of the detection signals into a pair of second Doppler signals representing the motion of the organ, the second interval starting at a moment which follows each of the trigger pulses by a second predetermined time; and means for calculating a difference in phase between the pair of the first Doppler signals and the pair of the second Doppler signals to detect blood velocity.

Claim 4

An ultrasonic blood velocity detector comprising: an ultrasonic probe emitting ultrasonic waves into an examined body and converting echoes of the emitted ultrasonic waves into an echo signal; means for generating trigger pulses at a predetermined period; means for generating a drive pulse signal synchronous with the trigger pulses; means for driving the ultrasonic probe by use of the drive pulse signal; means for generating a pair of reference signals orthogonal to each other; means for processing the echo signal into a pair of detection signals through orthogonal detection by use of the pair of the reference signals; means for integrating the pair of the detection signals for a first interval during which the echo signal represents a flow of blood within the examined body, and for converting the pair of the detection signals into a pair of first Doppler signals representing the flow of the blood, the first interval starting at a moment which follows each of the trigger pulses by a first predetermined time; means for integrating the pair of the detection signals for a second interval during which the echo signal represents a motion of an organ within the examined body, and for converting the pair of the detection signals into a pair of second Doppler signals representing the motion of the organ, the second interval starting at a moment which follows each of the trigger pulses by a second predetermined time; and means for calculating a difference in phase between the pair of the first Doppler signals and the pair of the second Doppler signals to detect blood velocity.

Claim 5

An ultrasonic blood velocity detector comprising: an ultrasonic probe emitting ultrasonic waves into an examined body and converting echoes of the emitted ultrasonic waves into an echo signal; means for generating a continuous drive signal having a predetermined frequency; means for driving the ultrasonic probe by use of the continuous drive signal; means for generating a pair of reference signals orthogonal to each other and equal to the continuous drive signal in frequency; means for processing the echo signal into a pair of Doppler signals through orthogonal detection by use of the pair of the reference signals; a pair of low pass filters extracting clutter components from the Doppler signals and deriving a pair of clutter signals from the extracted clutter components; and means for calculating a difference in phase between the pair of the Doppler signals and the pair of the clutter signals to detect blood velocity.

Claim 6

An ultrasonic blood velocity detector comprising: an ultrasonic probe emitting ultrasonic waves into an examined body and converting echoes of the emitted ultrasonic waves into an echo signal; means for generating a continuous drive signal having a predetermined frequency; means for driving the ultrasonic probe by use of the continuous drive signal; means for generating a pair of reference signals orthogonal to each other and equal to the continuous drive signal in frequency; means for processing the echo signal into a pair of Doppler signals through orthogonal detection by use of the pair of the reference signals; a pair of low pass filters extracting clutter components from the Doppler signals and deriving a pair of clutter signals from the extracted clutter components; and means for calculating a difference in phase between the pair of the Doppler signals and the pair of the clutter signals to detect blood velocity.