Signal to Noise Ratio PDF

# Signal to Noise Ratio * The signal-to-noise ratio (S/N) is a much more useful figure of merit than noise alone for describing the quality of an analytical method or the performance of an instrument * Signal to noise ratio (SNR) = Ratio of signal level to noise level * This ratio describes the qua...

# Signal to Noise Ratio * The signal-to-noise ratio (S/N) is a much more useful figure of merit than noise alone for describing the quality of an analytical method or the performance of an instrument * Signal to noise ratio (SNR) = Ratio of signal level to noise level * This ratio describes the quality of instrumental method ## SNR * SNR > 1, The signal is more than the noise. * SNR < 1, the noise level is bigger than the signal level. * The impact of noise increases as the signal is lowest * The signal processors: * Amplifier → increase signal * Attenuator → decrease noise ## Instrumental Noise * Noise is associated with each component of an instrument-that is, with the source, the input transducer, all signal-processing elements, and the output transducer. * Some types of noise are impossible to avoid in a measurement * Noise-free data can never be realized in the lab. ## Signals and Noise * In most measurements, the average strength of the noise N is constant and independent of the magnitude of the signal S. * The effect of noise on the relative error of a measurement becomes greater as the quantity being measured decreases in magnitude. ## Signal to Noise Ratio * There is always some noise in analytical signals * Noise is independent on the signal * **SIGNAL** -> Information about the analyte * **NOISE** -> Unwanted Information not related to analyte