Patent application number | Description | Published |
20090274028 | Multi-bit phase alignment for synchronization mark pattern matching - Embodiments of the present invention relate to the detection of synchronization marks in data storage and retrieval. To detect a synchronization mark, embodiments of the present invention require both pattern matching and proper phase alignment, following a repeating synchronization field. According to one particular embodiment, proper phase alignment following a repeated four bit synchronization field, is utilized in conjunction with pattern matching, to identify a synchronization mark. By allowing a synchronization mark to be identified only with proper phase alignment at the earliest possible occurrence of the synchronization mark, accuracy of synchronization mark detection may be improved. | 11-05-2009 |
20090274247 | Detection of synchronization mark from output of matched filter upstream of viterbi detector - Embodiments of the present invention relate to the detection of synchronization marks in data storage and retrieval. According to one embodiment, synchronization marks are detected from the output of a matched filter, upstream of the Viterbi detector. This approach avoids the delay associated with the latency of the Viterbi output, thereby allowing time to align parity framing and to properly start the time-varying trellis. Certain embodiments disclose 34- and 20-bit primary synchronization marks located at the beginning of a data region. Other embodiments disclose 16-, 20-, and 24-bit embedded synchronization marks located within a data region. | 11-05-2009 |
20130100550 | IMPLEMENTING MAGNETIC DEFECT CLASSIFICATION USING PHASE MODULATION - A method, apparatus, and system are provided for implementing magnetic defect classification using phase modulation for hard disk drives. A magnetic media readback signal of a hard disk drive is processed to identify predefined phase modulation (PM) characteristics to implement magnetic defect classification of magnetic media bump and pit defects. | 04-25-2013 |
20130308220 | IMPLEMENTING CHANNEL SIGNAL PROCESSING ASSIST WITH ECS CONTACT DETECTION - A method, apparatus, and system for implementing channel signal processing assist with an embedded contact sensor (ECS) in hard disk drives. An ECS signal is captured during write and idle operation of the hard disk drive. A read channel monitors changes in the ECS signal providing a clearance monitor function for insuring write integrity. | 11-21-2013 |
20130335841 | IMPLEMENTING COMBINED PHASE AND AMPLITUDE MAGNETIC DEFECT DETECTION ON-THE-FLY - A method, apparatus, and system are provided for implementing magnetic defect location detection on-the-fly for hard disk drives. A magnetic media readback signal of a hard disk drive is demodulated to generate phase modulation (PM) and amplitude modulation (AM) signals. A new coordinate plane defined by a combined phase modulation (PM) and amplitude modulation (AM) phasor-defect detector calculation function used to locate magnetic defects on-the-fly. | 12-19-2013 |
20140201590 | Disk Drive with Distributed Codeword Blocks - Disk drives are described in which blocks of data spanning multiple sectors are encoded into a plurality of codewords which are then divided into segments that are physically separated (distributed) on the disk surface over multiple sectors in a distributed codeword block so that the codewords have an improved worst case SNR in comparison to individual sectors. This results in more even SNR performance for each codeword, which improves the performance for portions of a track which have lower than the average SNR. Embodiments are described in which the distributed codeword blocks span across tracks. | 07-17-2014 |
20150077875 | DISK DRIVE WITH DIFFERENT SYNCHRONIZATION FIELDS AND SYNCHRONIZATION MARKS IN THE DATA SECTOR PREAMBLES IN ADJACENT DATA TRACKS - A hard disk drive has disks with data sector preambles that allow for inter-track interference. The same data sector preamble is used for all data sectors in a track but the preamble in each track is different from the preamble in radially adjacent tracks. In a first embodiment each preamble includes a synchronization field (SF) and synchronization mark (SM) that are the same in each track but different from the SF and SM in radially adjacent tracks. Only two unique SFs and two unique SMs are required, with the two SFs and two SMs alternating in radially adjacent tracks. In a second embodiment the preambles are “integrated”, meaning that the preamble is a sequence of bits that does not include separate dedicated fields, like SF and SM. The preamble bit sequences are decoded using matched filters to provide bit synchronization and start-of-data information. | 03-19-2015 |
20150077876 | DISK DRIVE WITH DIFFERENT DATA SECTOR INTEGRATED PREAMBLES IN ADJACENT DATA TRACKS - A hard disk drive has disks with data sector preambles that allow for inter-track interference. The same data sector preamble is used for all data sectors in a track but the preamble in each track is different from the preamble in radially adjacent tracks. In a first embodiment each preamble includes a synchronization field (SF) and synchronization mark (SM) that are the same in each track but different from the SF and SM in radially adjacent tracks. Only two unique SFs and two unique SMs are required, with the two SFs and two SMs alternating in radially adjacent tracks. In a second embodiment the preambles are “integrated”, meaning that the preamble is a sequence of bits that does not include separate dedicated fields, like SF and SM. The preamble bit sequences are decoded using matched filters to provide bit synchronization and start-of-data information. | 03-19-2015 |