single-tone keying

例句：

1. 1. The music was composed using a single-tone keying technique.
   这首音乐使用了单音键调技术创作。
2. 2.The radio station employs a mono-tonal keying system to broadcast its programming.
   该广播电台采用单音键调系统进行节目广播。
3. 3. The new software uses a mono-tonal keying method to enhance sound quality.
   这款新软件采用了单音键调方法来提升音质。