Noise characterization of perpendicular magnetic media using autocorrelation method

Frequency-domain analysis using the measured noise spectrum has usually been used for medium noise analysis. However, with this method it is impossible to observe where the noise occurs and how the reproduced waveform behaves. On the other hand, time-domain analysis using the autocorrelation function enables the spatial distribution of noise to be visualized. Recently, the transition position jitter and the transition width fluctuation have been recognized as noise sources in perpendicular magnetic recording. In this paper, some of these noise sources of actual readback waveforms were estimated by using autocorrelation method. The result of this work was that the noise in perpendicular magnetic recording could be visualized and power ratio of several noise sources was calculated. And it was confirmed that the jitter is the most dominant noise source.