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为什么频率偏移能引起相位旋转？
提问者：抽抽学文化
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提问时间：2013-10-12 16:49
在一篇资料中看到如下内容：
Carrier frequency offset (CFO) is caused by the mismatch between the transmitter oscillator and the receiver oscillator. In this paper, we assume that the CFO is small enough and hence the inter-carrier interference (ICI) caused by the CFO can be neglected. However, the small CFO will still result in phase rotation effect.
we also assume that the timing offset (TO) is small enough, i.e. the timing is in the range of guard interval, and hence the inter-symbol interference (ISI) will not be occurred. Also, the small TO will still result in phase rotation effect.
时域的时偏引起频域的相位旋转能够理解，可是为什么频偏也能引起频率频率偏转吗？
如果频偏为φ，那么频域表示难道不应该是X(f-φ)吗？为什么会对相位造成影响呢？
这个是OFDM系统。
请各位赐教
Carrier frequency offset (CFO) is caused by the mismatch between the transmitter oscillator and the receiver oscillator. In this paper, we assume that the CFO is small enough and hence the inter-carrier interference (ICI) caused by the CFO can be neglected. However, the small CFO will still result in phase rotation effect.
we also assume that the timing offset (TO) is small enough, i.e. the timing is in the range of guard interval, and hence the inter-symbol interference (ISI) will not be occurred. Also, the small TO will still result in phase rotation effect.
时域的时偏引起频域的相位旋转能够理解，可是为什么频偏也能引起频率频率偏转吗？
如果频偏为φ，那么频域表示难道不应该是X(f-φ)吗？为什么会对相位造成影响呢？
这个是OFDM系统。
请各位赐教
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最佳答案
最佳答案通信还是通讯 的答案
( 采纳时间：2014-5-27 17:14 )
以单音信号为例子，没有频率偏移的信号为a*exp（j2pift+fa），其中a是幅值，f是频率，fa是初始相位，假设有频偏△f，则信号变为a*exp(j2pi(f+△f)t+fa)=a*exp(j2pift+△ft+fa)，此时相位就是一个随时间变化的相位△ft+fa
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回答时间：2014-1-14 12:45
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