Multi - frequency的用法和样例：
例句
- An underwater acoustic communication scheme using time delay and multiple frequency modula-tion technique is presented in this paper.
研究了一种采用脉冲时延差和多频码元组合编码的水声通信技术。 - While single frequency tones worked on certain phone routes, the most common signaling on the then long distance network used Multi-Frequency tones.
而某些单频音调闪耀电话线最常见的则长途信令网采用多频音调。
