| 摘要 |
PURPOSE:To execute control to select the variable diameter of an annular and to reduce gain difference between focus steps by executing ON/OFF control to an ultrasonic receiving circuit group by a receiving operation control means independently for each channel. CONSTITUTION:Ultrasonic waves are exchanged with a patient by an annular array type probe 4 composed of the ring elements of annular array oscillators 1-3 and received echo signals are amplified by blocks 5-7. Since the receiving operation is controlled to the blocks 5-7, gain control signals and ON/OFF control signals are respectively sent from a control part 8 to the blocks 5-7. The gain control signals are sent to preamplifiers P1-P8 independently for each channel and on the other hand, the ON/OFF control signals are sent to contacts S1-S8 independently for each channel. Thus, at the time of operation for variable diameter and variable focus to execute annular variable diameter control, the gain difference can be suppressed to be small between the focus steps. |
