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 Figures 1 and 2 show the values of voltage against time for 8192 individual readings of a digital nanovoltmeter. Successive plots show the same data averaged over 4, 16 and 64 successive points. The readings in Figure 1 were taken with the input short-circuited. The noise is essentially white and successive averaging smoothes each plot with respect to that above.
| Figure 1 |
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The readings in Figure 2 were taken while measuring the voltage difference between a standard cell (whose noise is white) and a 1.018 V electronic voltage standard referenced to an internal Zener diode. This time the same averaging process smoothes the white noise components but leaves a persistent "skeleton" characteristic of correlated noise, in this case 1/f noise.
| Figure 2 |
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Summary
