  In this paper we suggest a new algorithm for determination of signal-to-noise
ratio (SNR). SNR is a quantitative measure widely used in science and
engineering. Generally, methods for determination of SNR are based on using of
experimentally defined power of noise level, or some conditional noise
criterion which can be specified for signal processing. In the present work we
describe method for determination of SNR of chaotic and stochastic signals at
unknown power levels of signal and noise. For this aim we use information as
difference between unconditional and conditional entropy. Our theoretical
results are confirmed by results of analysis of signals which can be described
by nonlinear maps and presented as overlapping of harmonic and stochastic
signals.
