four-frequency diplex telegraphy

例句：

1. 1. The new communication system employs four-frequency diplex telegraphy to improve data transmission efficiency.
   新通信系统采用四频复用电报来提高数据传输效率。
2. 2. In the early days of radio, four-frequency diplex telegraphy was a crucial technology for transmitting signals over long distances.
   在无线电的早期，四频复用电报是传输远距离信号的关键技术。
3. 3. The engineers developed a four-frequency diplex telegraphy system that could handle multiple simultaneous calls.
   工程师们开发了一个四频复用电报系统，能够同时处理多个呼叫。