In highfrequencycommunication, extremely low SNR communication is an expedient means.
在短波通信中，极低信噪比条件通信是一种应急通信手段。
2
A single carrier modulation scheme suitable for use in highfrequencycommunication systems is provided that achieves improved residual frequency error and phase noise estimation.
提供了一种实现改进残留频率误差和相位噪声估算的、适合于在高频通信系统中使用的单载波调制方案。
3
Highfrequency pulsed sounds might be used for echolocation, and low frequency time continuous signals related with communication and emotive state expression.