Modulation noise measurements of high density recording channels using MR heads

Modulation noise measurements were made on several tape samples using an unshielded magnetoresistive (MR) head. The very high sensitivity of the MR head makes possible the detection of the media noise above other noise sources not associated with the recording medium, such as head resistance and preamplifier noise. The effect of track width on modulation noise was investigated. It has been shown previously that modulation noise, which is multiplicative in nature, is not purely Gaussian but also contains a significant exponential component. The implications of the non-Gaussian nature of this noise for amplitude qualifier level setting and for error rates in peak-detecting and partial-response channels are discussed. >