| 摘要 |
PURPOSE:To improve a signal noise ratio of a doppler signal supplied to a doppler circuit for a blood flow inspection by providing a plurality of received wave phasing circuits, adding ultrasonic wave signals from the aforesaid circuits and sending the added signals to the doppler circuit. CONSTITUTION:An ultrasonic wave from a probe 1 is reflected in a physical body, and an oscillator receives a reflected echo signal. The received reflected echo signal is converted into an electrical signal and amplified in the fist stage amplifier circuit 3. Then, the signal is sent to a plurality of received wave phasing circuits 4 and 5. Signals with directivity slightly dephased are supplied to the aforesaid plurality of received wave phasing circuits 4 and 5. furthermore, signals from the plurality of the received wave phasing circuits 4 and 5 are added in an addition circuit 8 and sent to a drive circuit 20 after addition. Namely, the addition of the ultrasonic wave signals from the circuits 4 and 5 ensures that a noise due to an amplifier therein is reduced for the ultrasonic wave signal, and the S/N ratio is thereby improved. |
