Editing Signal-to-noise ratio (section)

===Dynamic range===
The concepts of signal-to-noise ratio and dynamic range are closely related. Dynamic range measures the ratio between the strongest un-[[distortion|distorted]] signal on a [[Communication channel|channel]] and the minimum discernible signal, which for most purposes is the noise level. SNR measures the ratio between an arbitrary signal level (not necessarily the most powerful signal possible) and noise. Measuring signal-to-noise ratios requires the selection of a representative or ''reference'' signal. In [[audio engineering]], the reference signal is usually a [[sine wave]] at a standardized [[nominal level|nominal]] or [[alignment level]], such as 1&nbsp;kHz at +4 [[dBu]] (1.228 V<sub>RMS</sub>).

SNR is usually taken to indicate an ''average'' signal-to-noise ratio, as it is possible that instantaneous signal-to-noise ratios will be considerably different. The concept can be understood as normalizing the noise level to 1 (0&nbsp;dB) and measuring how far the signal 'stands out'.