| 摘要 |
PURPOSE:To perform both small delay and large delay phasing with high accuracy not depending on a signal frequency by dividing a reception wave phasing circuit into an analog phasing circuit which performs the small delay phasing and a digital phasing circuit which performs the large delay phasing, and inserting a selector circuit between the analog phasing circuit and the digital phasing circuit. CONSTITUTION:A probe 1 to which a pulse is sent from a wave transmission driver 2 sends an ultrasonic wave to a subject, and the same probe receives a reflected wave from the inside of the subject. The reflected wave converted to an electrical signal is inputted to the analog phasing circuit 3, and small delay required for reception focusing is applied to the signal at the circuit. Next, a delay processing for the reception focusing is completed by applying large delay to the signal. However, at this time, the large delay is performed by unifying a signal line corresponding to the reception focusing and the same delay quantity can be applied. Therefore, the signal lines to which the same large delay are applied are unified at the selector circuit 4, and they are inputted to the digital phasing circuit 5. The digital phasing circuit 5 applies the large delay to an input signal, and performs addition on respective signal line, and it is detected, and after that, output is sent to an image display device 6, then, a tomographic image can be obtained. |
