A NEW THEORY OF RECORDING MEDIA NOISE

Previous investigations of the noise in particulate or grainy recording media have considered statistical variations in the processes by which the particles become magnetized. The theory of noise presented here includes also statistical variations in the packing density of the particles. An extremely simple analysis shows that when both of these phenomena are included properly, the noise power of recording media may always be expected to depend upon the magnetization, or signal level, and the particle packing factor. It is found that the recording media should always provide higher signal-to-noise ratios (SNR's) than was previously supposed. It is pointed out that the signal recovery or detection techniques employed today in magnetic storage devices cannot yield optimum SNR's or bit error rates. Finally, some algebraic and/or conceptual errors in the published literature on noise are discussed.