A study of PRML systems for perpendicular recording using double layered medium

Okamoto, Yoshihiro; Sumiyoshi, H.; Kishigami, Tomo; Akamatsu, M.; Osawa, Hisashi; Saito, Hidetoshi; Muraoka, H.; Nakamura, Y.

doi:10.1109/20.908343

Cited by 20 publications

(6 citation statements)

References 3 publications

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“…4 shows the BER performances using different target responses and linear equalizers for 3% jitter. Since is a widely used standard target for perpendicular channels [15], we also include the performance of VD with this fixed target for the purpose of comparison. The detection performance of VD on a jitter-free channel using a monic-constrained GPR target designed for 0% jitter is included in Fig.…”

Section: Computational and Simulation Resultsmentioning

confidence: 99%

“…This is similar to the approach used in [13], [11]. On the other hand, several papers use a different SNR definition where the noise power is taken as the sum of the powers of electronics noise and jitter noise, with the jitter noise power computed based on either single transition or multiple transitions [12], [15], [19]. Since jitter noise and electronics noise have very different effect on the detection performance, defining the SNR by adding the powers of these noises may lead to inconsistent results.…”

Section: Additional Commentsmentioning

confidence: 99%

“…Okamoto et al [14] extended the data-dependent noise prediction approach to perpendicular recording to deal with jitter noise. The performance of several standard PR targets (with integer-valued coefficients) for perpendicular channels with jitter noise was studied by Okamoto et al [15].…”

Section: Introductionmentioning

confidence: 99%

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Joint design of optimum partial response target and equalizer for recording channels with jitter noise

Yang

Mathew

2006

IEEE Trans. Magn.

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Section: Computational and Simulation Resultsmentioning

confidence: 99%

Section: Additional Commentsmentioning

confidence: 99%

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Joint design of optimum partial response target and equalizer for recording channels with jitter noise

Yang

Mathew

2006

IEEE Trans. Magn.

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“…Therefore, it is intuitively clear that a partial response target with DC content would be the best choice for the perpendicular recording system in the absence of disturbances other than additive Gaussian noise (for a PRML system). Examples of such partial response targets have been proposed in [3], [4]. However, the MR head used in current magnetic recording systems is susceptible to low-frequency disturbances.…”

Section: Introductionmentioning

confidence: 98%

Read channel issues in perpendicular magnetic recording

Gopalaswamy

McEwen²

2001

IEEE Trans. Magn.

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Perpendicular recording is an alternative to longitudinal recording that shows promise in mitigating the super-paramagnetic limit. This channel passes DC and thus presents challenges to the read channel design. Compounding the problem, the MR head signal is susceptible to thermal asperities which manifest as low-frequency disturbances. We compare the performance of a DC-coupled PRML channel architecture which uses a non-DC-free target with a first-order DC loop to remove low-frequency disturbances to that of an alternate architecture that uses a DC-free target. We show through analysis and simulation results that the former architecture degrades with increasing latency of the DC loop and performs worse than the DC-free target for large latencies. In addition, the detection performance with DC-free target can be improved by the use of a block code with single parity bit.

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“…shows the distribution of error events of the class II Partial Response (PR2) target, which is used in [20,75]. GPR targets are often used for perpendicular recording.…”

Section: (C)mentioning

confidence: 99%

Low-Density Parity Check Codes

Wu¹

2009

Contemporary Coding Techniques and Applications for Mobile Communications

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For high density magnetic recording channels and memory systems, low-density parity-check (LDPC) codes with probabilistic decoding are replacing Reed-Solomon (RS) codes or Bose-Chaudhuri-Hocquenghem (BCH) codes with conventional algebraic decoding. The main benefit of LDPC codes over the RS and BCH codes is that LDPC codes can provide lower error probabilities than equivalent conventional codes if the conditions of magnetic recording channels or memory systems are the same. In other words, in order to achieve the same error probabilities, LDPC codes can tolerate lower signal-to-noise-ratio conditions than the conventional codes, which can imply higher densities and lower media costs. These advantages of LDPC codes are possible at the cost of the increased decoder complexity over the conventional decoding.The main themes of this thesis are (1) to determine probabilistic input to the LDPC decoders from the channel detectors in magnetic recording channels or memory systems with low complexity and (2) AcknowledgmentsI would like to thank Prof. Kumar for providing me with a unique opportunity and an ideal environment to study signal processing and error correcting codes for data storage and memory systems. I respect his patience and believing in students. I was very lucky and I will miss the time I stayed here.I would like to thank Prof. Bain, Prof. Li, and Dr. Cheng for reading my thesis during their busiest time and providing many suggestions and very detailed feedback.I would also like to thank Dr. Cheng for bringing my interest into the fascinating problem of protecting memory systems on spacecraft and for his very detailed comments on the manuscripts of the papers on this topic.

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A study of PRML systems for perpendicular recording using double layered medium

Cited by 20 publications

References 3 publications

Joint design of optimum partial response target and equalizer for recording channels with jitter noise

Joint design of optimum partial response target and equalizer for recording channels with jitter noise

Read channel issues in perpendicular magnetic recording

Low-Density Parity Check Codes

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