Digital signal processor, error detection method, and recording medium reproducer

Number of patents in Portfolio can not be more than 2000

United States of America Patent

PATENT NO 5774470
SERIAL NO

08524040

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ATTORNEY / AGENT: (SPONSORED)

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Abstract

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A playback signal processing circuit for reducing decode errors and enabling high-density digital magnetic recording and a digital magnetic recording reproducing unit using the playback signal processing circuit are provided. An estimated waveform generation circuit uses the decoding result of a PRML channel to generate an ideal playback signal waveform. A subtractor provides a waveform representing a difference between the waveform and an actual playback signal. There is a high probability that error bits will occur at an interval of two or four bits because of the nature of GCR code and maximum-likelihood decoding; in the error state of each bit, one bit is incremented by one with respect to the correct bit value and the other signal bit is decremented by one. From this fact, an error detection circuit discriminates an error difference waveform pattern and an error discrimination circuit detects an error bit interval, whereby an error correction circuit carries out error bit correction.

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Patent Owner(s)

Patent OwnerAddressTotal Patents
HITACHI GLOBAL STORAGE TECHNOLOGIES JAPAN, LTD.TOKYO379

International Classification(s)

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Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Ashikawa, Kazutoshi Maebashi, JP 8 117
Mita, Seiichi Tsukui, JP 74 1137
Miyazawa, Shoichi Yokohama, JP 29 369
Nishiya, Takushi Machida, JP 16 409
Shimokawa, Ryushi Takasaki, JP 11 95

Cited Art Landscape

Patent Info (Count) # Cites Year
 
MOTOROLA, INC. (5)
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* 5144644 Soft trellis decoding 30 1989
* 5113400 Error detection system 38 1990
* 5142551 Signal weighting system for digital receiver 60 1991
* 5263052 Viterbi equalizer for radio receiver 13 1991
* Cited By Examiner

Patent Citation Ranking

Forward Cite Landscape

Patent Info (Count) # Cites Year
 
CIRRUS LOGIC, INC. (2)
6185175 Sampled amplitude read channel employing noise whitening in a remod/demod sequence detector 44 1998
* 6513141 Sampled amplitude read channel employing a trellis sequence detector and a post processor for generating error metrics used to correct errors made by the trellis sequence detector 33 1999
 
SHARP KABUSHIKI KAISHA (1)
* 7080313 Signal evaluation apparatus and signal evaluation method 6 2002
 
KONINKLIJKE PHILIPS ELECTRONICS N V (3)
7058142 Generation of amplitude levels for a partial response maximum likelihood (PRML) bit detector 2 2003
* 7827456 Error correction scheme for a disc-playing system 1 2005
* 2007/0226,575 Error Correction Scheme for a Disc-Playing System 5 2005
 
LUCENT TECHNOLOGIES INC. (1)
* 6317071 Method and apparatus for analog-to-digital conversion by combining digital sample values 4 2000
 
SEAGATE TECHNOLOGY LLC (1)
6877116 Method and apparatus for determining bit error rate in a sampled data system without requiring read channel circuitry 6 1998
 
Astec International LLC (1)
6397173 Application specific waveform generator 8 1999
 
KONINKLIJKE PHILIPS ELECTRONICS N.V. (1)
* 6587520 Generation of amplitude levels for a partial response maximum likelihood (PRML) bit detector 2 1999
 
DOLBY LABORATORIES LICENSING CORPORATION (4)
* 7617109 Method for correcting metadata affecting the playback loudness and dynamic range of audio information 18 2004
* 2006/0002,572 Method for correcting metadata affecting the playback loudness and dynamic range of audio information 78 2004
8032385 Method for correcting metadata affecting the playback loudness of audio information 8 2009
* 2010/0250,258 Method for Correcting Metadata Affecting the Playback Loudness of Audio Information 11 2009
 
TEXAS INSTRUMENTS INCORPORATED (3)
* 6546518 Detector error suppression circuit and method 10 2000
* 7016445 Apparatus for and method of clock recovery from a serial data stream 14 2001
* 2003/0031,283 Apparatus for and method of clock recovery from a serial data stream 1 2001
 
KABUSHIKI KAISHA TOSHIBA (1)
* 2006/0092,804 Digital data reproducing apparatus and method 11 2005
 
AVAGO TECHNOLOGIES GENERAL IP (SINGAPORE) PTE. LTD. (7)
* 5961658 PR4 equalization and an EPR4 remod/demod sequence detector in a sampled amplitude read channel 48 1997
* 6052248 Parity channel code for enhancing the operation of a remod/demod sequence detector in a d=1 sampled amplitude read channel 48 1998
6185173 Sampled amplitude read channel employing a trellis sequence detector matched to a channel code constraint and a post processor for correcting errors in the detected binary sequence using the signal samples and an error syndrome 26 1998
* 9021325 Classifying bit errors in transmitted run length limited data 0 2013
* 2014/0223,270 CLASSIFYING BIT ERRORS IN TRANSMITTED RUN LENGTH LIMITED DATA 0 2013
* 9267991 Classifying bit errors in transmitted run length limited data 0 2015
* 2015/0205,653 CLASSIFYING BIT ERRORS IN TRANSMITTED RUN LENGTH LIMITED DATA 0 2015
* Cited By Examiner