The effect of bandpass filters for thermal asperity suppression in perpendicular recording systems

Koonkarnkhai, Santi; Kovintavewat, Piya; Keeratiwintakorn, Phongsak

doi:10.1109/ecticon.2009.5137219

Cited by 2 publications

(2 citation statements)

References 11 publications

(17 reference statements)

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“…The proposed TA suppression method has a similar structure presented in [3], which consists of two SOVA detectors working concurrently, one for the target H(D), and the other for the target G(D)H(D) equipped with a bandpass filter G(D) = 1 -D 2 [9]. This bandpass filter is selected to eliminate the TA effect while capturing most energy of the readback signal, because the PMR channel has significant low-frequency content.…”

Section: Proposed Ta Suppression Methodsmentioning

confidence: 99%

An Improved TA Suppression Method for Coded PR Channels

Kovintavewat

Koonkarnkhai

2014

AMR

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Thermal asperity (TA) resulting from the collision between the slider and the asperity on a magnetic medium during read process can deteriorate the performance of hard disk drives (HDDs). Without TA detection and correction algorithms, the system performance can be unacceptable, depending on how severe the TA is. This paper presents an improved TA suppression method for coded partial response (PR) channels, which consists of two channels running in parallel. Specifically, one channel is matched to the target H(D), while the other is matched to the target H(D)G(D), where G(D) = 1 – D2 is a bandpass filter and D is a delay operator. The soft-output Viterbi algorithm (SOVA) detector in the H(D) channel yields the high-quality soft information in absence of the TA, while that in the G(D)H(D) channel produces the high-quality soft information in presence of the TA. Then, the overall soft information chosen from these two detectors, depending on if a TA is detected or not, is sent to the decoder according to the turbo equalization principle. Experimental results show that the proposed method performs better than the conventional and the previously proposed ones, when operating at high signal-to-noise ratio (SNR) region where a practical HDD works.

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Section: Proposed Ta Suppression Methodsmentioning

confidence: 99%

An Improved TA Suppression Method for Coded PR Channels

Kovintavewat

Koonkarnkhai

2014

AMR

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“…Similar to [6], "Method 3" employs the two VDs running in parallel as depicted in Fig. 2, i.e., one for the H(D) target and the other for the G(D)H(D) target, where G(D) = 1 -D 2 is a bandpass filter [7] for eliminating the BLP effect. Practically, the VD for the H(D) target yields low bit-error rate (BER) in the absence of the BLP, whereas that for the G(D)H(D) target offers low BER in the presence of the BLP.…”

Section: Blp Detection and Correction Algorithmsmentioning

confidence: 99%

Baseline Popping Detection and Correction Algorithms for Perpendicular Magnetic Recording System

Kovintavewat

Koonkarnkhai

2014

AMR

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Hard disk drives (HDDs) employ the magneto-resistive (MR) head to sense the change in magnetic flux via the transitions of magnetization pattern, resulting in a readback signal. Thus, head instability plays an important role on the reliability of HDDs because it can deteriorate the system performance considerably. Baseline popping (BLP) is one of the crucial problems caused by the head instability, whose effect can distort the readback signal to the extent of causing a sector read failure. This paper proposes three BLP detection and correction algorithms for a perpendicular magnetic recording (PMR) system. Specifically, to suppress the BLP effect experienced in the readback signal, the first algorithm is based on an averaging filter and a threshold detector; the second one relies on the estimated BLP signal obtained from a linear curve fitting technique; and finally the third one uses two sequence detectors running in parallel. Experimental results indicate that the third algorithm performs better than the other schemes because it can detect and correct the BLP better than the others, especially when the peak BLP amplitude is large.

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The effect of bandpass filters for thermal asperity suppression in perpendicular recording systems

Cited by 2 publications

References 11 publications

An Improved TA Suppression Method for Coded PR Channels

An Improved TA Suppression Method for Coded PR Channels

Baseline Popping Detection and Correction Algorithms for Perpendicular Magnetic Recording System

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