Underwater acoustic channel is a time-space-frequency variant channel, having a character for narrow bandwidth, high ambient noise level and strong interference of multipath.

而由此构成的水声信道是一个空间与频率响应随机快速变化的传输信道，存在窄带、高噪及强多途干扰。

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With the highest level of noise immunity, ClearPad 3400 performs with precision even in the presence of noise interference, which can be exacerbated by a range of factors, including the use of noisy handset power supplies.

ENGADGET: Synaptics launches a pair of mobile touchscreens at MWC 2013