A stochastic theory apprach is used to characterize the noise from particulate recording media, which has been established to be signal dependent and nonstationary. It is indicated that the media noise is completely characterized stochastically by determining its autocorrelation function. The inadequacy of power spectrum measurements, obtained from a spectrum analyzer, in determining the autocorrelation function of nonstationary noise is discussed. The nonstationary media noise is then modeled in the time domain in terms of two stationary stochastic processes, and one deterministic function of time. The consistency of this noise model with experimental observations of background noise and modulation noise is demonstrated. The deterministic function of time in this model is calculated from the signal, and the autocorrelation functions of the component stationary stochastic processes are determined from spectrum analyzer measurements. From these, the autocorrelation function of the nonstationary media noise is deduced. The advantages of this technique, as opposed to time-domain measurements, in deducing the autocorrelation function are discussed.
ASJC Scopus subject areas
- Physics and Astronomy(all)