Digital video recording

Umemoto, M.; Eto, Yoshizumi; Fukinuki, Takahiko

doi:10.1109/5.390122

Cited by 10 publications

(8 citation statements)

References 38 publications

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“…The spectral response function in this case is the Fourier transform (FT) of the horizontal field in the head face plane (1) where , and is the wavelength of the recorded signal. For a head with a recessed leading pole, the tape will travel parallel to the face of the trailing pole and hence, the same definition for the spectral response has been used for these heads.…”

Section: Methodsmentioning

confidence: 99%

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Eddy-current-assisted digital video read/write head

2001

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The paper describes write fields and replay characteristics of gapped heads with magnetically recessed leading poles for high-frequency digital video. It describes an investigation by finite-element analysis and compares computed results for laminated Sendust and Co 91 Nb 6 Zr 3 heads and discusses the effects due to depositing a layer of copper inside the leading gap edge. Recessing the leading pole yields an asymmetric field, while eddy currents in the copper layer cause an advantageous redistribution of flux in the head. Predicted increases in both maximum horizontal field and horizontal field gradient by at least 130% and 17% are predicted for Sendust and Co 91 Nb 6 Zr 3 heads, respectively, at 100 MHz. Hence, such a head can write on higher coercivity media than a conventional gapped head. The playback performance is also improved by an extension of the frequency response. The paper gives a linear model for the phase of the spectral response, valid over a wide range of frequencies, for each of two leading pole recessions.Index Terms-Digital magnetic recording, eddy currents, finite element methods, magnetic recording/reading heads, video recording.

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Section: Methodsmentioning

confidence: 99%

“…T HE DEMAND for greater data densities in digital magnetic recording has led to the use of high coercivity media [1]. Helical scan systems are no exception to this where metal particle and metal evaporated tapes have been developed for digital video and data backup.…”

Section: Introductionmentioning

confidence: 99%

Eddy-current-assisted digital video read/write head

2001

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“…Iteration 1 proceeds as follows (16) No erased digits in the initial array can be resolved using the column-wise hints without possibly making an error, i.e., two erasures in column 1 could be resolved either as or as . The same applies to in column 2.…”

Section: Iterative Decoding Of Concatenated Codesmentioning

confidence: 99%

“…and still cannot be resolved because they could either both be 1 or 0, and is not involved in any row constraint. Iteration 2 starts with the rightmost expression of (16) and tries to resolve the remaining erasures using again the constraints on columns and rows, i.e. (17) First, single erasure in column 2 is resolved as , whereas two erasures in column 1 cannot be uniquely resolved.…”

Section: Iterative Decoding Of Concatenated Codesmentioning

confidence: 99%

“…Magnetic disk drives and tapes, digital audio tape, and digital video tape are important examples of magnetic recording applications, while compact disc, DVD, and rewritable DVD are among such optical recording systems. In the recording process of many of these systems, the data are first encoded by one or more error correcting encoders, followed by a modulation code and a partial response channel [16]- [18]. The error correcting codes are usually Reed-Solomon (RS) codes or their variants, e.g., shortened codes or product codes.…”

Section: A Existing Recording Systemsmentioning

confidence: 99%

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On iterative decoding in some existing systems

Bajcsy

Chong

Garr

et al. 2001

IEEE J. Select. Areas Commun.

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Iterative decoding is used to achieve backward compatible performance improvement in several existing systems. Concatenated coding and iterative decoding are first set up using composite mappings, so that various applications in digital communication and recording can be described in a concise and uniform manner. An ambiguity zone detection (AZD) based iterative decoder, operating on generalized erasures, is described as an alternative for concatenated systems where turbo decoding cannot be performed. Described iterative decoding techniques are then applied to selected wireless communication and digital recording systems. Simulation results and utilization of decoding gains are briefly discussed.

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