The concepts of signal-to-noise ratio and dynamic range are closely related. This may cause some confusion among readers, but the the signal and the noise pdf download factor is not significant for typical operations performed in signal processing, or for computing power ratios. Sometimes SNR is defined as the square of the alternative definition above.

All real measurements are disturbed by noise. It is often possible to reduce the noise by controlling the environment. When the signal is constant or periodic and the noise is random, it is possible to enhance the SNR by averaging the measurement. In this case the noise goes down as the square root of the number of averaged samples.

When a measurement is digitized, the number of bits used to represent the measurement determines the maximum possible signal-to-noise ratio. This theoretical maximum SNR assumes a perfect input signal. SNR in a digitally modulated signal. Each extra quantization bit increases the dynamic range by roughly 6 dB. Note that the dynamic range is much larger than fixed-point, but at a cost of a worse signal-to-noise ratio.

This makes floating-point preferable in situations where the dynamic range is large or unpredictable. Fixed-point’s simpler implementations can be used with no signal quality disadvantage in systems where dynamic range is less than 6. The very large dynamic range of floating-point can be a disadvantage, since it requires more forethought in designing algorithms. This way the noise covers a bandwidth that is much wider than the signal itself. The resulting signal influence relies mainly on the filtering of the noise. The OSNR is the ratio between the signal power and the noise power in a given bandwidth. Most commonly a reference bandwidth of 0.

This bandwidth is independent of the modulation format, the frequency and the receiver. The exact methods may vary between fields. Maximum possible full scale signal can be charged as peak-to-peak or as RMS. 9 dB more SNR for video. Sarunic, Changhuei Yang, Joseph A. Sensitivity advantage of swept source and Fourier domain optical coherence tomography.