The frequency range of R-wave has been determined by use of frequency analysis.

并且根据频谱分析的方法确定了瑞利波的频率分布范围。

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You can do this by room (bedroom, kitchen, etc), by frequency of use (seasonal items, everyday items, etc.), or by purpose (work-related items, entertainment, etc).

你可以按房间分类(如卧室，厨房等)，按使用频率分类(季节性用品，日常用品等)，或按目的分类(工作相关物品，娱乐物品等)。

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Many of the TV frequency bands have been vacated by TV's move to digital, so, in a country hungry for wireless resources, it was proposed that this spectrum get redirected to mobile access use.

当电视信号变为数字信号后，许多电视的频率带宽都被闲置下来。 因此，在一个渴望无线资源的国家，这些频带被引向移动接入应用可谓众望所归。

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ADS-B promises to make air traffic control easier, cheaper and in many ways safer by allowing planes to transmit their locations by radio frequency instead of depending on towers to use radar to track and coordinate them.

FORBES: Next-Gen Air Traffic Control Vulnerable To Hackers Spoofing Planes Out Of Thin Air

But Switzerland's train system is second only to Japan's for its comprehensiveness and frequency of use by locals.

BBC: Switzerland by public transport

State intervention is justified only by the chaos that would be caused by a free-for-all over the use of the frequency spectrum.

ECONOMIST: Letters