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一、概述过去,在 NRZI,PM,FM,MFM、MNRZJ(GCR),M~2FM(即改进“0”的 MFM),M~3F-M(即 MMFM)等各种记录方式中,使用的都是矩形写电流,在低密度情况下,读出时和写电流翻转点相对应的是高斯分布的读出信号(图1),然而在高密度情况下,就会出现脉冲拥挤效应即读出信号不但会产生峰值位移Δl(图2),而且,还将造成基线歪扭、倾斜,其峰值位移Δl 的大小和基线偏摆的程度,依所记录的数据图象而异,也就是说,对确定的记录方式而言,记录某一种数据图象对,峰值位移和基线歪扭、倾斜得特别严重。(如对 MFM,恶重恶劣
I. OVERVIEW In the past, in various recording methods such as NRZI, PM, FM, MFM, MNRZJ (GCR), M ~ 2FM (MFM for improving “0 ”) and M ~ 3F-M Rectangular write current is used. At low density, the readout signal is Gaussian distributed readout signal corresponding to the write current flip-flop (Figure 1). However, at high density, the pulse crowding effect That is, the readout signal not only produces a peak shift Δ1 (Figure 2) but also causes skew and skew of the baseline, the magnitude of its peak shift Δ1 and the degree of baseline skew, depending on the recorded data image In other words, for a given recording method, the recording of a particular data image pair is particularly severe with peak shifts and baseline skew. (Such as the MFM, wicked