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Signal averaging is a signal processing technique applied in the time domain, intended to increase the strength of a signal relative to noise that is obscuring it. By averaging a set of replicate measurements, the signal-to-noise ratio, S/N, will be increased, ideally in proportion to the square root of the number of measurements. == Deriving the SNR for averaged signals == Assumed that * Signal is uncorrelated to noise, and noise is uncorrelated : . * Signal power is constant in the replicate measurements. * Noise is random, with a mean of zero and constant variance in the replicate measurements: and . * We (canonically) define Signal-to-Noise ratio as . === Noise power for sampled signals === Assuming we sample the noise, we get a per-sample variance of . Averaging a random variable leads to the following variance: . Since noise variance is constant : , demonstrating that averaging realizations of the same, uncorrelated noise reduces noise power by a factor of . 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Signal averaging」の詳細全文を読む スポンサード リンク
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