Interlaced magnetic recording (IMR) shows potential to achieve higher areal density capability (ADC) than conventional magnetic recording by recording tracks in an interlaced manner [1]. Top and bottom tracks can be recorded in different frequencies such that the bit error rate (BER) performance can be balanced, providing extra track or linear density pushes. For example, heat assisted IMR (HIMR) enables higher ADC than conventional heat assisted magnetic recording (HAMR) and shingled recorded HAMR by allowing broader bottom tracks with sharper bit transitions and narrow top tracks by control the heat spot [2]. On the other hand, bottom tracks in IMR can suffer from sever inter-track interference (ITI) by subsequent top track writes on both sides, especially as the track density increases [3]. In order to mitigate the ITI effect for such double-sided squeezed tracks, customized ITI cancellation scheme has been introduced, where the asynchronously written tracks are processed in the oversampled domain and overall ADC can be improved [4]. In this study, ITI cancellation scheme is extended for generalized IMR framework, where the ITI can be distributed for top and bottom tracks by applying dual write configurations. One of the major contributions of the tangible ADC gain by HIMR is the additional laser spot control to form narrow but sharp bit transitions in top tracks [2]. In this manner, the wide and sharp bottom tracks are only partially erased by the subsequent top track writes, and, thus, the ITI can be effectively managed. Likewise, the write track widths can be modulated for conventional perpendicular recording and may provide the ADC gain once the ITI is efficiently handled. Note that ITI cancellation can also be needed for top tracks as well, and the relative linear density differences of ITI can be both positive and negative. Therefore, flexible ITI cancellation scheme is proposed in this study to handle the widely varying synchronization issues. The waveforms need to be over-sampled first to effectively synchronize the neighboring tracks, and double of baud rate of lower density track can be used. For example, under 2500 and 2000 kBPI dual writer configurations, the oversampled data can be denoted as x(t)2x, x(b)1.6x respectively, relative to its baud rate. Then, the error signal is first estimated, e(t)2x, e(b)1.6x, resampled to the side track data rate, e'(t)1.25x, e'(b)0.8x, and then the ITI response is estimated for tracks mt and mb as, {h'(t)mt-1, h'(t)mt+1}=arg minh(t)mt-1,h(t)mt+1 || e'(t)1.25x - h(t)mt-1*n展开▼
