%0 Journal Article
%T A SCHEME TO CONTROL THE FIRST-SECOND CYCLE AMPLITUDE RATIO OF TRANSDUCERS FOR ULTRASONIC MEASUREMENTS<br>控制超声测量用换能器首次波幅度比的方案
%A YING CHONG-FU
%A LI MING-XIAN
%A ZHONG GAO-QI
%A LIU XIAN-DUO
%A YANG YU-RUI
%A <br>应祟福
%A 李明轩
%A 钟高琦
%A 刘献铎
%A 杨玉瑞
%J 物理学报
%D 1981
%I 
%X In the ultrasonic applications of measuring non-acoustic characteristics, it is impor-tant that the time of flight of the ultrasound be measured with accuracy. One significant step to achieve this is to ensure that the first few cycles of the received ultrasonic signal should not be missed. This in turns asks for the amplitude of the first cycle being as large as, or greater than, that of the second. By studying the transient responses of the transmitting and receiving transducers, either separated or two united in one, it is shown that the first second cycle amplitude ratio can be increased from less than one to one or more of the specific acoustic resistance of the transducer backing is enhanced to a suf-ficiently high value, but not necessarily as high as the specific acoustic resistance of the piezoelectric plate. This holds for the case of light loading. For the case of heavy load-ing, the amplitude ratio is found to be inherently large.
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=6E709DC38FA1D09A4B578DD0906875B5B44D4D294832BB8E&cid=47EA7CFDDEBB28E0&jid=29DF2CB55EF687E7EFA80DFD4B978260&aid=575AC6CEB049C79D1FF9C4F5DB15EF13&yid=AA64127AB7DEB65D&vid=340AC2BF8E7AB4FD&iid=CA4FD0336C81A37A&sid=C753EB8AC8F551B9&eid=6700D0D256586E73&journal_id=1000-3290&journal_name=物理学报&referenced_num=0&reference_num=0