Dynamic information storage or retrieval – Binary pulse train information signal – Binary signal level detecting using a reference signal
Reexamination Certificate
1999-03-04
2001-08-21
Edun, Muhammad (Department: 2651)
Dynamic information storage or retrieval
Binary pulse train information signal
Binary signal level detecting using a reference signal
C369S124010, C369S124150
Reexamination Certificate
active
06278675
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a waveform equalizer for use in a recording information reproducing apparatus for reproducing recording information from a recording medium.
2. Description of Related Art
To improve the S/N ratio of a read signal read out from a recording medium on which digital data has been recorded at a high density, there is a known technique to perform a waveform equalization by executing a filtering process to emphasize high frequency components for the read signal.
Although an improvement rate of the S/N ratio can be raised as a degree of emphasis of the high frequency components for the read signal is increased, there is a problem such that if the high frequency components is excessively emphasized, an intersymbol interference increases and a jitter contrarily occurs.
The invention has beem made to solve this problem and it is an object of the invention to provide a waveform equalizer which can improve an S/N ratio without causing a jitter in a read signal read out from a recording medium.
OBJECTS AND SUMMARY OF THE INVENTION
According to the invention, there is provided a waveform equalizer for obtaining an equalization correction read signal by performing a waveform equalization to a read signal read out from a recording medium, comprising: amplitude limiting means for obtaining an amplitude limitation read signal by limiting an amplitude level of the read signal by a predetermined amplitude limitation value; and a filter for outputting a signal obtained by performing a filtering process to the amplitude limitation read signal as an equalization correction read signal.
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Forney et al., “Combined Equalization and Coding Using Precoding”, IEEE Communications Magazine, 29 (1991) Dec. No. 12, NY, pp. 25-34.
Hollmann, Henk D., “The General Solution of Write Equalization for RLL (d,k) Codes, 8097 IEEE Transactions on Informatioin Theory”, 37(1991) May, No. 3, NY, pp. 856-862.
Tobita et al., “Viterbi Detection of Partial Response on a Magneto-Optical Recording Channel”, 166/SPIE vol. 1663 Optical Data Storage (1992), pp. 166-173.
Search Report dated Jun. 17, 1999.
Kuribayashi Hiroki
Miyanabe Shogo
Edun Muhammad
Fish & Richardson P.C.
Pioneer Electronics Corporation
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