PROBLEM TO BE SOLVED: To provide an ultrasonic diagnostic apparatus capable of preventing saturation in an amplifier for amplifying an echo signal without deteriorating an ultrasonic image.SOLUTION: An ultrasonic diagnostic apparatus includes: a transmission part for allowing a transmission signal to transmit an ultrasonic signal to a subject via an ultrasonic probe and a reception part for processing a reception signal obtained by reflection inside the subject. The reception part includes: a transmission/reception changeover switch part for transmission/reception separation in order to prevent a transmission signal from sneaking to the reception part an amplification part for amplifying a reception signal and an attenuation part which is arranged between the transmission/reception changeover switch part and the amplification part and attenuates the reception signal. The attenuation part changes an attenuation amount from a large amount to a small amount with a lapse of a reception time so that it attenuates a reflection signal from a short distance for the reception of a signal with large amplitude immediately after the end of transmission, and does not attenuate a signal from a long distance with small signal amplitude.COPYRIGHT: (C)2013,JPO&INPIT【課題】超音波画像を劣化させることなく、エコー信号を増幅する増幅器の飽和を防止することが可能な超音波診断装置を提供すること。【解決手段】超音波診断装置は、送信信号が超音波プローブを介して被検体に超音波信号を送信する送信部と、被検体内で反射されて得られた受信信号を処理する受信部を備える。受信部は、送信信号の受信部への回り込みを防止する送受分離のための送受切換えスイッチ部と、受信信号を増幅する増幅部と、送受切換えスイッチ部と増幅部の間に配置され、受信信号を減衰させる減衰部とを備える。減衰部は、送信終了直後から大振幅の信号を受信する近距離からの反射信号を減衰させ、信号振幅の小さい遠距離から信号を減衰させないように、受信時間の経過と共に減衰量を大から小へ変化させる。【選択図】図1
