2008/08/24

香农极限 带宽计算公式

今天在西西河看到了 有人讲香农公式 http://www.ccthere.com/article/696151
不禁要感慨这人太牛了。给我们呈现了一种物理学中简单的美~~~

具体来说
  • If S/N >> 1, then
 C \approx 0.332 \cdot B \cdot \mathrm{SNR (in \ dB)}
where
\mathrm{SNR (in \ dB)} = 10\log_{10}{S \over N}
  • Similarly, if S/N <<>
 C \approx 1.44 \cdot B \cdot {S \over N}
In this low-SNR approximation, capacity is independent of bandwidth if the noise is white, of spectral density N0 watts per hertz, in which case the total noise power is B \cdot N_0.
 C \approx 1.44  \cdot {S \over N_0}
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