短語詞組短語echo wave signal 回波信號ultrasonic echo -signal 超聲回波信號echo -signal 回聲信號radar -echo-signal 雷達回波信號sea echo signal 海洋回波echo signal curve 回音曲線amplitude modulated echo signal 調(diào)幅回波信號target echo signal modeling 信號回波模型pulse echo signal 脈沖回波信號 返回 echo signal