同轴线缆——1929
发明人：Herman Andrew Affel和Lloyd Espenschied。其成就是1835031号专利“同轴电缆”。
左为Affel 右为Espenschied。这张照片摄于1949年，在AT&T纪念同轴系统发明二十周年的庆典上，发明人Lloyd Espenschied (左）手持一段早期用于试验的同轴线，与另一发明人Herman Affel一起在回忆在贝尔试验室的这段馈线革命的辛苦历程。1929年申请专利的同轴馈线，在1940年以后开始逐步投入商用，并在AT&T的系统中大量使用。
发明故事：Affel和Espenschied两人于1929年在AT&T的贝尔实验室发明了当时称为同心传导系统的同轴线缆。同轴线缆使得在长距离线路上同时传输数千个电话呼叫成为可能。1940年，同轴线缆首次投入商用；一年后，AT&T用同轴线缆在明尼阿波利斯和斯蒂文市之间构建了一个传输系统，可同时传输480个话音信号和1套电视节目。1983年，同轴线缆终于让路给了光纤线缆。但不可否认的是，如果没有同轴线缆，局域网就不可能成为现实。
个人简介编辑本段回目录
Lloyd Espenschied (27 April 1889 – June 1, 1986) was an American electrical engineer.
Lloyd Espenschied等Biography
He was born in St. Louis, Missouri and in 1901 he moved to Brooklyn, New York, to live with relatives of his mother. He became an amateur radio operator in 1904 and later worked as a shipboard wireless operator for the United Wireless Telegraph Company during summer vacations. He graduated from the Pratt Institute in 1909 with a degree in applied electricity and then worked as an engineer for the American affiliate of the German Telefunken Wireless Telegraph Company. Among his assignments was the installation of the Telefunken quenched spark system on ships of the US Navy. He joined the Engineering Department of AT&T in 1910 and remained with the Bell Company until he retired in 1954. At the Bell Company, he worked on the design of loading coils used to enhance telephonic communication by wire, and he also was a participant in long-distance radio telephone experiments using a vacuum-tube transmitter conducted by Bell engineers during 1915.
Lloyd Espenschied和Herman Andrew Affel He was sent to Pearl Harbor, Hawaii, to test reception from a transmitter in Arlington, Virginia. Starting in 1916 he worked with several colleagues, including Herman A. Affel, on a carrier multiplex system which was put in operation between Baltimore, Maryland, and Pittsburgh, Pennsylvania, in 1918. He applied for a patent in 1927 on the use of piezoelectric quartz crystals in band-pass filters. He and Affel jointly received a patent on a wideband coaxial cable system of transmission which was disclosed in a prize-winning paper published in AIEE's Electrical Engineering in October 1934. He also contributed to the development of wire distribution of radio programming used in network radio. He patented a collision avoidance system using reflected waves for railroad trains in 1924 and later applied similar techniques for a radio altimeter for aircraft which was produced commercially by the Western Electric Company beginning in 1937. He received the IRE Medal of Honor in 1940 'For his accomplishments as an engineer, as an inventor, as a pioneer in the development of radio telephony, and for his effective contributions to the progress of international radio coordination.' and the Pioneer Award of the IEEE Aerospace and Electronic Systems Group in 1967.
Memberships
He joined the Wireless Institute, which later merged with the Society of Wireless Telegraph Engineers in 1912 to form the IRE. He was recorded as a discussant of the first paper published in the Proceedings as well as three other papers in the first volume. He became a Fellow of the IRE in 1924 and a Fellow of the American Institute of Electrical Engineers (AIEE) in 1930.
