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RMS

The square root of the average squared deviation, a fair measure of how strongly something is shaking.

The RMS of a window's deviations is sqrt((1/N) Σ (x_i - x̄)²); a sine of amplitude A has RMS A/√2.

Examples

  • A window of 1040, 960, 1040, 960 mg has a mean of 1000 and an RMS of the deviations of 40 mg.

  • A 40 mg sine has an RMS of 28.3 mg; with 12 mg of noise added, the lab's windows measure 29 to 31 mg.

See also

peak-to-peak feature zero crossing
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