  This paper concerns theoretical modeling of degradation of signal with OFDM
coding caused by pseudo-random nonlinear distortions introduced by an
analog-to-digital or digital-to-analog converter. A new quantity, effective
number of samples, is defined and used for derivation of accurate expressions
for autocorrelation function and the total power of the distortions. The
derivation is based on probabilistic model of the signal and its transition
probability. It is shown, that for digital (discrete and quantized) signals the
effective number of samples replaces the total number of samples and is the
proper quantity defining their properties.
