短語詞組短語echo wave signal 廻波信號ultrasonic echo -signal 超聲廻波信號echo -signal 廻聲信號radar -echo-signal 雷達(dá)廻波信號sea echo signal 海洋廻波echo signal curve 廻音曲線amplitude modulated echo signal 調(diào)幅廻波信號target echo signal modeling 信號廻波模型pulse echo signal 脈沖廻波信號 返回 echo signal