An advanced read/write channel for magnetic disk storage

Behrens, R.T.; Armstrong, A.J.

doi:10.1109/acssc.1992.269079

Cited by 21 publications

(21 citation statements)

References 6 publications

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“…Figure 3 gives the curves of 10 consecutive captured sets of filter coefficients from the same drive, plotted on top of each other. The abscissa is the index of the filter coefficients (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12), the ordinate is the value of the corresponding coefficient byte (P1-P12). A curve plotted in one color shows the 12 filter coefficient values of one example set, connected by straight lines.…”

Section: Data Dependenciesmentioning

confidence: 99%

“…The noise sources and levels have been extensively studied in [3,4], their effects on the signal in the read channel have also been investigated in [5][6][7][8]. The resulting inherent randomness in the channel filter coefficients has been proposed for use for random number generators in [9], but the included randomness extraction algorithm is very inefficient.…”

Section: Introductionmentioning

confidence: 99%

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An Efficient Noise Generator for Validation of Channels Equalizers

Panda¹,

Panigrahi²,

Padhy³

2011

JSIP

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Section: Data Dependenciesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Efficient Noise Generator for Validation of Channels Equalizers

Panda¹,

Panigrahi²,

Padhy³

2011

JSIP

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“…One of the commonly used codes that reduces the complexity of the matching detector in the E PR4 channel is the rate 2/3 (1, 7) runlength-limited (RLL) code [30]. The resulting trellis has 10 states, compared with 16 states for a full trellis.…”

Section: Trellis Reduction By Coding Constraints and Rate 8/9 Tmmentioning

confidence: 99%

Reduced complexity sequence detection for high-order partial response channels

Leung

Nikolić²,

Fu³

et al. 2001

IEEE J. Select. Areas Commun.

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Abstract-Detector hardware complexity of high-order partial response magnetic read channels is a major obstacle to high data rate operation and reduced area and power consumption. The method presented here reduces the complexity of single-step and two-step implementations of the Viterbi detector by applying a distance-enhancing code that eliminates some states from the code trellis. The complexity of the detector is further reduced by eliminating less-probable branches from the trellis. This is accomplished by a simple control mechanism that uses the signs of the consecutive input samples. The reduced set of add-compare-select (ACS) units is dynamically assigned to the detector states, decreasing the complexity of the Viterbi detector by roughly 50%. This method is demonstrated on high-order partial response systems with the E 2 PR4 target and an 11-level/32-state target. The simulation results show negligible bit error rate (BER) degradation for signal-to-noise ratios in the range of operation of contemporary disk drive read channels.

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“…Wood [67] observed that a code increased the minimum squared-Euclidean distance of the partial response class 2 (PR2) constraint, corresponding to the PR polynomial by a factor of . In [6], Behrens and Armstrong observed that the constraint increased the minimum squared-Euclidean distance on the E PR4 channel by a factor of . Moreover, incorporating the constraint into the detector trellis actually reduced the required number of trellis states.…”

Section: Introductionmentioning

confidence: 99%

“…The constraint also reduced the number of detector states relative to uncoded E PR4, although not to the same extent as the constraint. (McEwen and Wolf [36] extended the code design in [6] in a different direction. They designed codes for E PR4 with squared distance by using the modulo-construction--a variation of MSN codes-introduced by Fredrickson [17].…”

Section: Introductionmentioning

confidence: 99%

Constrained coding for binary channels with high intersymbol interference

Karabed

Siegel

Soljanin

1999

IEEE Trans. Inform. Theory

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Partial-response (PR) signaling is used to model communications channels with intersymbol interference (ISI) such as the magnetic-recording channel and the copper-wire channel for digital subscriber lines. Coding for improving noise immunity in higher order partial-response channels, such as the "extended" class-4 channels denoted EPR4, E 2 PR4, E 3 PR4, has become an important subject as the linear densities in magnetic recording approach those at which these partial-response channels are the best models of real channels. In this paper, we consider partialresponse channels for which ISI is so severe that the channels fail to achieve the matched-filter bound (MFB) for symbol error rate, assuming maximum-likelihood decoding. We show that their performance can be improved to the MFB by high-rate codes based on constrained systems, some of which may even simplify the Viterbi detectors relative to the uncoded channels. We present several examples of high-rate constrained codes for E 2 PR4 and E 3 PR4 channels and evaluate their performance by simulation.

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An advanced read/write channel for magnetic disk storage

Cited by 21 publications

References 6 publications

An Efficient Noise Generator for Validation of Channels Equalizers

An Efficient Noise Generator for Validation of Channels Equalizers

Reduced complexity sequence detection for high-order partial response channels

Constrained coding for binary channels with high intersymbol interference

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