第二次世界大战期间,美、英曾用字母表示各种雷达的工作频段。在没有必要说明准确的工作频率或为了保密起见,采用这种表示法是很方便的。不过,这种至今还在使用的表示法所用字母是混乱的,字母顺序与频率高低之间毫无关系。随着指挥-控制-通信、雷达和电子对抗等军用电子技术的发展, During the Second World War, the United States and Britain used letters to indicate the working frequency bands of various radars. It is convenient to use this notation when it is not necessary to specify the exact frequency of work or for the sake of confidentiality. However, the letters used in the notation that is still in use are confusing, and alphabetical order has nothing to do with the frequency. With the development of military electronic technologies such as command-control-communications, radar and electronic warfare,