ACS Instrument Practice Test

Signal averaging means combining multiple scans of the same measurement and using their average as the final value. The true signal is the same in each scan, while random noise fluctuates from scan to scan. When you average N scans, the signal contributions add coherently and stay about the same, but the random noise, being uncorrelated, tends to cancel out. This reduces the noise level by roughly the square root of N, so the signal-to-noise ratio improves by about sqrt(N). For example, averaging four scans yields about a twofold improvement in SNR. This is why taking multiple scans is a common practice to boost measurement quality. The mean signal does not inherently increase with averaging, noise does not increase, and averaging does not inherently reduce peak resolution, so the dominant effect is the enhancement of SNR through noise reduction.