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7433141 Data randomization for rewriting in recording/reproduction apparatus  
A data recording/recovery device ( 20 ) comprises a packet generator ( 34 ) for including recordable information into a packet ( 44 ), the packet initially having a nominal run length limited (RLL)...
7379452 Synchronous read channel  
A synchronous read channel having a single chip integrated circuit digital portion which provides digital gain control, timing recovery, equalization, digital peak detection, sequence detection,...
7372652 Correcting errors in disk drive read back signals by iterating with the Reed-Solomon decoder  
A read channel includes a signal receiver that receives a read back signal and a signal detector to detect symbols in the read back signal. The signal detector includes a first detector that...
7359132 Equalization preamble region in digital data storage (DDS) format  
A magnetic tape includes plural diagonal tracks, each storing a preamble sequence close to user data such that a transducer for reading the track reads the preamble sequence immediately before...
7286065 Method and apparatus for DC-level constrained coding  
A method and apparatus reduces a DC level of an input word. The input word is divided into a plurality of components that include n symbols. The n symbols of the components are summed for each...
7253979 Method and device for data read/write, recording medium, and program product  
A data read/write device includes a data write-processing unit that performs amplitude modulation on write data to obtain an amplitude-modulated signal that contains a plurality of amplitude...
7199955 Decoding apparatus and decoding method  
In a coding method which does not restrict a run length of “1” while data is recorded/reproduced, there are such a drawback that when an error correction is carried out, a total number of error...
7095340 Run-length violation detection circuitry and methods for using the same  
Circuitry for detecting excessive runs of similar bits of data in a data stream is provided. The data stream is typically received as serial data operating in a serial clock domain. Run-length...
7071851 Techniques for implementing non-uniform constraints in modulation encoded data  
Non-uniform modulation encoding techniques are provided to prevent data from containing bit patterns that are prone to errors during read back. Modulation encoding is performed on a data stream to...
7064687 Techniques for modulating data using short block encoders  
Techniques are provided for applying modulation constraints to data streams using a short block encoder. A short block encoder encodes a subset of the bits in a data stream. Then, the even and odd...
7042666 Disk drive having improved timing marks  
A disk drive has timing marks (TMs) on the disk, that are chosen to reduce the probability of misidentification of a TM in the presence of read errors. The disk drive searches for TMs within a...
7031085 Version tracking of disk write operations  
The present invention is a disc drive storage unit incorporating novel apparatus, data structure and method for uniquely identifying data written during each write command operation of the disc...
6999259 Master disc and method of manufacturing the same  
Magnetic transfer can be performed with high reliability by shortening the magnetic transit interval of servo address information, that is, a section in which “0” or “1” continues. An area...
6992856 Systems for limiting channel control values to thereby improve servo-demodulation robustness  
Systems are provided for limiting channel control values, such as servo automatic gain control (AGC) values and/or servo phase lock loop (PLL) values, within respective desired ranges. Keeping such...
6992855 Methods for limiting channel control values to thereby improve servo-demodulation robustness  
Methods are provided for limiting channel control values, such as servo automatic gain control (AGC) values and/or servo phase lock loop (PLL) values, within respective desired ranges. Keeping such...
6961197 Correcting errors in disk drive read back signals by iterating with the Reed-Solomon decoder  
A signal detector to detect symbols in a read back signal. The signal detector includes a first detector to generate raw decisions as a function of the read back signal. A post processor identifies...
6947232 User data wedge media certification apparatus and method  
Method and apparatus for detecting defects in a magnetic medium of a data handling system. The magnetic medium includes a number of user data wedges each disposed between an adjacent pair of servo...
6930845 Data writing and reading  
Method and apparatus for recording data on a magnetic recording medium and writing data to a computer bus in which the data is divided into words of a predetermined length, a signal is generated...
6922297 Double-attribute method of encoding and decoding magnetic data  
A method of encoding and decoding data involving the simultaneous application of pulse width modulation and pulse position modulation systems to data intended for storage on a magnetic disk medium.
6894855 Magnetic disk drive including read channel for processing differentiated read signal  
A disk drive of perpendicular magnetic recording method including a read head comprising a GMR element and a drive using a double-layered disk medium, is disclosed. In the magnetic field response...
6888480 Run-length violation detection circuitry and methods for using the same  
Circuitry for detecting excessive runs of similar bits of data in a data stream is provided. The data stream is typically received as serial data operating in a serial clock domain. Run-length...
6829306 Method and apparatus of converting a series of data words into a modulated signal  
The present invention relates to method and apparatus of converting a series of data words into modulated signals. This method divides a data word, which a sync signal is to be added in front or...
6819512 Triple-attribute method of encoding and decoding magnetic data  
A method of encoding and decoding data involving the simultaneous application of pulse amplitude modulation, pulse width modulation, and pulse position modulation systems to data intended for...
6775082 Digital VFO phase control device  
A digital VFO phase control device comprising: an output signal generation means for generating an output signal having the predetermined phase relationship with an input signal of the digital VFO...
6768603 Precompensation technique and MTR code for high data rate recording  
A method for write-precompensating a waveform for magnetically recording a waveform on a magnetic medium is disclosed. A user data stream is encoded into an encoded data stream so that the encoded...
6744580 Method and apparatus for reproducing data and method and apparatus for recording and/or reproducing data  
A magnetic recording and/or reproducing apparatus performing efficient decoding to lower a decoding error rate. A magnetic recording and/or reproducing apparatus 50 includes a modulation SISO...
6735028 Method and apparatus for increasing data storage capacity via phase and amplitude modulation  
The capacity and realized data rate of a data storage medium is increased by storing multiple bits per symbol using digital modulation techniques. Both phase and amplitude modulation techniques can...
6731228 Method and apparatus of converting a series of data words into a modulated signal  
The present invention relates to method and apparatus of converting a series of data words into modulated signals. This method generates for each data word a number of intermediate sequences by...
6704154 Decoding apparatus and decoding method  
In a coding method which does not restrict a run length of “1” while data is recorded/reproduced, there are such a drawback that when an error correction is carried out, a total number of error...
6678104 Equalization pre-amble region in digital data storage (DDS) format  
A method of encoding a digital data stream for writing to a digital storage (DDS) format tape data storage medium comprises writing a byte stream to a preamble region, immediately preceding a user...
6678103 Methods and apparatus for increased magnetic coding density by precise placement of magnetic transitions  
Methods and apparatus for increasing the density of data storage on a magnetic medium by using variations in positioning of magnetic transitions to encode bits. Conventionally encoded bits are...
6657800 Viterbi detector and method for recovering a binary sequence from a read signal  
A Viterbi detector receives a signal that represents a binary sequence having groups of no more and no fewer than a predetermined number of consecutive bits each having a first logic level, where...
6647445 Data transmission by an alternating frequency analog signal  
The present invention provides for the compression of digital and analog data for storage and transmission. Analog data in the form of an analog signal is converted into a digital signal by an...
6597526 Magnetic tape drive apparatus including a variable rate encoder  
The present invention comprises a magnetic recording system including a partial response, maximum likelihood recording channel incorporating fixed frequency read signal sampling and a digital...
6577460 Method and apparatus for improving track format efficiency in a direct access storage device  
An apparatus and method for transferring data between a read/write transducer and a data storage medium provides for improved track format efficiency. Data is written to a data sector of the data...
6577255 Method and apparatus for encoding digital data  
Encoding tables are accorded with variable-length encoding rules using a variable constraint length. A DSV control bit is periodically inserted into a first input bit stream to generate a second...
6553541 Reduced-complexity sequence detection  
Reduction of the complexity of a Viterbi-type sequence detector is disclosed. It was based on elimination of less probably taken branches in the trellis. The method is applied to the design of the...
6549351 Auxiliary data encoding in a disk drive system  
A disk drive system comprises control circuitry and a disk device. The disk device transfers a read signal representing user data, servo data, and auxiliary data to the control circuitry. The...
6532122 Data storage apparatus and magnetic recording method  
A data storage apparatus for magnetic recording and regeneration on a medium. Only in case of a dibit or Tri-bit code sequence in MTR codes having a restricted number of magnetic transition...
6493161 Pulse-mode writer  
A pulse-mode data writing protocol is disclosed which reduces the time required to implement a transition in the direction of magnetization of a recording medium, and which reduces the total power...
6473252 Biphasic multiple level storage method  
A novel magnetic data storage method is disclosed for storing digital data in a magnetic medium. According to the present invention, the digital data is represented by the interval between two...
6441979 Apparatus for recording and reproducing digital information signals of different transmission rates  
In a digital information recording and reproducing apparatus of a rotary magnetic head type for selecting and recording a plurality of digital information signals having different transmission...
6430713 System and method for constructing low complexity block coders  
A method for designing a computer program for finding a low-complexity coder for constrained block codes for application to timing recovery or error control in data recording systems. The method...
6417788 High rate runlength limited codes for 10-bit ECC symbols  
A methodology for designing an implementing high rate RLL codes is optimized for application to 10-bit ECC symbols, and provides rate 20/21, rate 50/51, rate 90/91 and other modulation code rates...
6414814 Method and apparatus for minimizing once per revolution positional errors in single disc servo track writing  
A method for minimizing once per revolution (OPR) positional errors in a single disk servo track writer (STW) comprises clamping a disc having an outer edge in the servo track writer; spinning the...
6404573 Full and half-rate signal space detection for channels with a time-varying MTR  
A detector is provided to detect data values within a data signal that is sampled to provide temporally separated data samples. A first detector portion is configured to determine the location of a...
6400288 Method and apparatus for generating code words with shifted tribit error protection  
An encoder is provided that converts data words into code words. The code words, when concatenated together, are such that sub-strings of consecutive first symbols in the code words have no more...
6397276 Data transmission by an alternating-frequency analog signal  
The present invention provides for the compression of digital and analog data for storage and transmission. Analog data in the form of an analog signal is converted into a digital signal by an...
6393598 Branch metric compensation for digital sequence detection  
The present invention provides sequence detection which takes into account amplitude and/or time distortions caused by neighboring magnetization regions on the magnetic medium, wherein the...
6385255 Coding system and method for partial response channels  
A system and method for reading data to and writing data from multi-level (M-ary) partial response channels uses a trellis coder to encode an input bit stream sequence into a stream of multi-level...