signal-to-noise ratio level

5.56  signal-to-noise ratio level. Ten times the logarithm to the base ten of signal-to-noise ratio. Symbol, N_SN. Unit, decibel (dB).

Annotation 1      When measures proportional to signal power, S, and noise power, N, can be determined separately and independently, signal-to-noise ratio level is given by:

N_SN = 10 lg(S/N) dB.

Annotation 2      When measures proportional to signal and noise power cannot be determined separately and independently, the level of the ratio of signal-plus-noise to noise, N’_SN is given by:

N’_SN = 10 lg[(S+N)/N] dB.