| Patent application number | Description | Published |
|---|
| 20090002865 | Zone Based Timing Recovery For Bit Patterned Media - A method includes: producing a bit detection signal in response to a plurality of islands located in a plurality of zones of a bit patterned media, processing the bit detection signal to produce a synchronization signal, wherein the processing is dependent on characteristics of the islands in the zone containing the plurality of islands, and using the synchronization signal to control timing of writing to the bit patterned media. The synchronization signal can also be used to control timing of reading from the bit patterned media. | 01-01-2009 |
| 20090009901 | RETRY AND RE-READ FOR WRITE SYNCHRONIZATION - A method of detecting a cycle slip in a data string read from a bit patterned media and adjusting the data string to compensate for the cycle slip is disclosed. A system including a writeable data storage medium and a compensator configured to adjust data read from the data storage medium to compensate for a cycle slip during the writing of the data onto the storage medium is also disclosed. | 01-08-2009 |
| 20090059412 | Extracting Position Information Using User Data - A method is disclosed for determining position information of a transducer. At least a first code and a second code are chosen. The first code has different characteristics than the second code. User data written to a first sub-track is encoded with the first code and user data written to a second sub-track is encoded with the second code. The first code read from the first sub-track is obtained and the second code read from the second sub-track is obtained. Position information of the transducer is extracted from the obtained characteristics of the first code and the obtained characteristics of the second code. | 03-05-2009 |
| 20090067090 | NULL SERVO PATTERN FOR BIT-PATTERNED MEDIA - A patterned recording media comprises a segment and a null pattern formed in the segment. The segment comprises first and second rows of discrete magnetic elements separated by a non-magnetic material, and a row of non-magnetic material positioned between the first and second rows. The null pattern comprises consecutive groups of the discrete magnetic elements in the first and second rows of the segment. Each group in the first row has a magnetic polarity that is opposite the magnetic polarity of adjoining groups in the first row. Each group in the second row has a magnetic polarity that is opposite the magnetic polarity of adjoining groups in the second row. | 03-12-2009 |
| 20090086356 | Detecting and Correcting Insertion and Deletion of Bits for Bit Patterned Media Storage Systems - A method of determining errors in a data storage device is disclosed. The disclosed method includes receiving a first code word from the data storage device. The method further includes determining whether a data error exists in the code word by analyzing a plurality of subsequent code words. Detecting a data error includes calculating first, second, and third checksums for each of a plurality of subsequent code words and determining whether there is an insertion or deletion error based on the calculated checksums. A further method includes receiving location information of errors on a data medium and adjusting a write clock frequency to reduce the probability of creating errors on the data medium during a write process. | 04-02-2009 |
| 20090086360 | Low Complexity Servo Demodulation Algorithm for Probe Storage - A method of calculating a position error signal is provided. The method includes receiving an analog signal from a data channel and converting the analog signal to a one bit wide digital signal. The analog signal is converted to a digital signal at an oversampled frequency. The position error signal is then calculated by summing correlated oversampled digital signals. | 04-02-2009 |
| 20090086846 | CHANNEL ARCHITECTURE WITH MULTIPLE SIGNAL PROCESSING BRANCHES FOR A GIVEN PHYSICAL CHANNEL - A communication system includes a physical communication channel. A signal is transmitted across the communication channel from a transmit end of the channel to a receive end of the channel. A plurality of processing branches process the signal at the receive end of the communication channel. This reduces complexity of the receive channel, without reducing a bandwidth of the given communication channel, and without comprising performance. | 04-02-2009 |
| 20090207519 | Compensating the Effects of Static Head-Media Spacing Variations and Nonlinear Transition Shift in Heat Assisted Magnetic Recording - An apparatus comprises a storage medium, a recording head, a source of electromagnetic radiation, and a control circuit for modulating the source of electromagnetic radiation in response to a static deviation of a spacing between the recording head and the storage medium. A method of compensating a static deviation of a spacing between a recording head and a storage medium performed by the apparatus, and a method of precompensating for nonlinear transition shifts in a heat assisted magnetic recording system, are also provided. | 08-20-2009 |
| 20100027605 | OFF-TRACK AWARE EQUALIZER DESIGN FOR BIT-PATTERNED MEDIA - An equalizer employed in conjunction with bit-patterned media (BPM) is designed to take advantage of a common topology associated with BPM in which each data track is comprised of a plurality of sub-tracks. The equalizer-target filter pair is designed as multiple-input/multiple-output (MIMO) system, in which the readback signal is divided into readback signals associated with each sub-track. The MIMO equalizer takes into account differences in the channel response associated with each sub-track. A detector is configured to receive a plurality of equalized inputs provided by the MIMO equalizer, wherein the detector generates in response estimates of the user data stored on each of the plurality of sub-tracks. | 02-04-2010 |
| 20100118426 | WRITE CLOCK CONTROL SYSTEM FOR MEDIA PATTERN WRITE SYNCHRONIZATION - A write clock control system comprises a clock controller that determines a phase offset based on a phase difference between a write clock signal and a media pattern corresponding to a given timing synchronization field being read, and a phase interpolator that produces an updated write clock signal by updating the phase of the write clock signal in accordance with control signals that are based on the phase offset signal. | 05-13-2010 |
| 20100118428 | INTERSPERSED PHASE-LOCKED LOOP FIELDS FOR DATA STORAGE MEDIA SYNCHRONIZATION - Techniques are described for providing media-referenced timing for operations on a data storage medium. In particular, Phase-Locked Loop (PLL) synchronization fields may be interspersed within data fields of the medium and may be read to obtain timing measurements. The PLL fields are illustratively pre-recorded at predetermined intervals on the medium and have a fixed number of dots of the bit patterned medium between the PLL fields. Phase and frequency of a write clock may be controlled based on the read PLL fields to translate the timing measurements from the PLL fields into phase and frequency corrections to synchronize the write clock to the data storage medium, | 05-13-2010 |
| 20110032632 | TIMING RECOVERY DETECTOR - A timing detector adapted for timing recovery on a read-channel is disclosed to improve signal quality of an input signal and maintain a small loop latency. The timing detector selects bits within the input signal that are high quality for timing recovery and discards bits that are low quality. The selected bits are used to synchronize phase and frequency of a bit sampler with a read-back analog signal. High-pass and low-pass analysis filters may split the input signal into high-frequency and low-frequency sub-bands and equalizers may re-shape the sub-bands. High-pass and low-pass synthesis filters may construct an output signal from the high-frequency and low-frequency sub-bands. Scaling factors may correct for signal and disturbance variations in the sub-bands. A comparator may eliminate sampled bits within the detector signal that have a magnitude less than a threshold and assign a common magnitude to sampled bits that meet or exceed the threshold. | 02-10-2011 |
