Abstract: A system and method for adjusting the radial tilt, tangential tilt, or a combination of radial and tangential tilt of an optical detection unit in an optical disc reading system can include applying different weighting factors to different signal components depending on which detection area detects the component, measuring a value of a signal characteristic, such as signal-to-noise ratio, of two signals with different sets of weighting factors, and determining an adjustment factor to the radial tilt as a function of the of the measured signal characteristic values.

Abstract: Systems and techniques relating to interpreting signals on a noisy channel. A direct current (DC) correction can be applied to an input of a post processor outside of a main read path that supplies data detector output to the post processor. A signal processor, such as a read channel transceiver device usable in a magnetic recording system, has a main read path including a signal equalizer and a data detector. A post processor is responsive to the output of the data detector, and a DC control unit applies a DC correction to an input of the post processor outside of the main read path.

Abstract: A signal processing circuit includes a plurality of processing-circuit modules and a logic control circuit. The plurality of processing-circuit modules is configured to process an electrical signal. The plurality of processing-circuit modules has at least one processing parameter that is adaptively adjusted based on the electrical signal. The logic control circuit is configured to receive signals from the plurality of processing-circuit modules, validate the processing based on the received signals, and control a storage circuit to sample and store a value of the processing parameter when the processing is validated. Further, the logic control circuit is configured to control the storage circuit to maintain the value of processing parameter when the processing fails validation, and to control the storage circuit to recover the processing parameter in the plurality of processing-circuit modules to the stored value when the plurality of processing-circuit modules is disturbed by a defect.

Abstract: A system including a demodulator module, a timing module, and a writing module. The demodulator module demodulates a wobble signal having a first period using timing signals having a second period and generates a phase error signal based on the wobble signal. The wobble signal is generated based on wobble information stored on an optical medium. The first period is a first multiple of a channel bit period of the optical medium. The second period is a second multiple of the channel bit period. The timing module generates a clock signal based on the phase error signal. The writing module writes, based on the clock signal, a predetermined number of bits on the optical medium during the first period. The predetermined number of bits written during the first period is based on the second multiple in response to the second multiple being greater than the first multiple.

Abstract: An automated capability is provided in which an offset correction is automatically determined and routinely updated in order to reduce or otherwise eliminate data retrieval errors that may be caused by low level distortion in optical disc data storage recording, re-recording and retrieval system. The capability is implemented through an improved offset control loop for reading information from a modulated wobble signal with which the data is recorded to an optical disc data storage medium to provide detection of an offset and correction of that offset to facilitate implementation of precise timing synchronization and/or encoded information contact in the system. The offset detector measures a wobble signal and mathematically converts detected information regarding the measured wobble signal to an offset correction by integrating the wobble signal over a specific time interval and comparing the integrated value to an expected integrated value.

Abstract: In a perpendicular magnetic recording system, the data that is being written by the write channel is fed back into the read channel. The read channel processes the data and decides if the written sequence is likely to have very poor DC characteristics. If that is the case, the write channel changes a scrambler seed and rewrites the data using the new scrambler seed. The data may also be inspected for patterns that might cause large baseline wander before being written to disk, i.e., in the write channel. A data sequence may be repeatedly scrambled and encoded until an acceptable level of estimated DC-wander has been achieved. The data sequence may then be written to disk.

Abstract: A Viterbi decoder includes a decision generator configured to generate a full decision output. An error detector is configured to detect errors in the full decision output and generate a signal when the full decision output errors are detected.

Abstract: A signal detector comprises a first detector that generates raw decisions as a function of a read back signal. A selector generates a modified decision by at least one of applying a correction technique to soft information that is based on the raw decisions and marking an erasure in the soft information. A decoder decodes the modified decision to generate a final decision and determines whether a correct codeword is generated by evaluating the final decision. The decoder performs at least one of Reed-Solomon decoding, Bose Chaudhuri Hocquerghen (BCH) decoding, Hamming decoding, and Trellis decoding.

Abstract: Aspects of the disclosure provide an apparatus. The apparatus includes a pick-up unit, such as an optical pick-up unit, a wobble channel and a defect detector. The pick-up unit generates a push-pull signal corresponding to a wobbled track of a storage medium. The wobble channel includes circuits to receive the push-pull signal, obtain a wobble signal from the push-pull signal, and calculate a wobble amplitude metric based on the wobble signal. The defect detector compares the wobble amplitude metric to a threshold to detect wobble defects.

Abstract: A system includes a sampling module and a correction module. The sampling module is configured to sample an input signal at sampling points and to output samples. The correction module is configured to output a correction factor when the first one of the samples is preceded by a second one of the samples having a first polarity, and when the first one of the samples is followed by a third one of the samples having a second polarity that is opposite of the first polarity. The correction factor comprises a correction value that is based on at least one of the samples that precedes the first one of the samples. The correction value is used to correct the input signal at a first one of the sampling points corresponding to the first one of the samples.

Abstract: A defect is detected on a storage medium of a disk drive. A location of the defect is determined, within a smallest addressable unit of data stored on the storage medium. An indication of the location is stored in a memory. A location of a sensor of the disk drive relative to the data stored on the storage medium is monitored. A response of at least one of a defect detector of the disk drive, a read channel controller of the disk drive, and a servo controller of the disk drive is changed based on the location of the sensor relative to the data stored on the storage medium and the stored indication of the location of the defect.

Abstract: Aspects of the disclosure provide a signal processing circuit that has fast response time to sudden profile changes in an electrical signal. The signal processing circuit includes a processing path configured to process an electrical signal that is generated in response to reading data on a storage medium, and a feed-forward correction module. The feed-forward correction module is configured to detect a profile variation based the electrical signal in a time window, and correct the electrical signal in the time window based on the detected profile variation.

Abstract: A Viterbi decoder includes an early decision generator that generates an early decision output. An error detector detects errors in the early decision output and generates a signal when the early decision output errors are detected.

Abstract: Aspects of the disclosure provide a signal processing circuit to reconstruct data from an analog signal. The signal processing circuit includes an analog to digital converter (ADC), an equalizer, a first timing compensation module, a phase-shift module and a second timing compensation module. The ADC receives an analog input signal, samples the analog input signal based on a sampling clock signal, and converts the sampled analog input signal into a digital output signal. The equalizer equalizes the digital output signal. The first timing compensation module detects a first timing error based on the digital output signal, and adjusts the sampling clock signal based on the first timing error. The phase-shift module phase-shifts the equalized digital output signal based on a phase-shift signal. The second timing compensation module detects a second timing error based on the equalized digital output signal, and adjusts the phase-shift signal based on the second timing error.

Abstract: A storage device includes a signal processor that receives an input signal that includes a direct current (DC) voltage offset. An encoder receives the input signal from the signal processor and selectively inverts portions of the input signal based on at least one of an average DC value and a weighted DC value of the input signal.

Abstract: A defect is detected on a storage medium of a disk drive. A location of the defect is determined, within a smallest addressable unit of data stored on the storage medium. An indication of the location is stored in a memory. A location of a sensor of the disk drive relative to the data stored on the storage medium is monitored. A response of at least one of a defect detector of the disk drive, a read channel controller of the disk drive, and a servo controller of the disk drive is changed based on the location of the sensor relative to the data stored on the storage medium and the stored indication of the location of the defect.

Abstract: A media defect compensation system and method may decouple effects of asymmetry from baseline error compensation computations. In some embodiments, a switching mechanism passes a baseline error signal into a baseline loop when a determination is made that a baseline error signal is not affected by asymmetry, and otherwise freezes the baseline loop when asymmetry may influence baseline error calculations.

Abstract: Aspects of the disclosure provide a method for recording. The method includes receiving a tracking signal corresponding to a recording track on a storage medium, phase-locking an internal signal to the tracking signal by reducing a phase error generated based on the internal signal and the tracking signal, generating a phase bias, combining the phase bias into the phase error to phase-shift the internal signal from the tracking signal, and recording on the recording track based on the internal signal.

Abstract: A device and process to compensate for asymmetrical qualities of an analog input signal, if present, and generate a timing signal. The timing signal is then used for analog to digital conversion.

Abstract: A system and method for adjusting the radial tilt, tangential tilt, or a combination of radial and tangential tilt of an optical detection unit in an optical disc reading system can include applying different weighting factors to different signal components depending on which detection area detects the component, measuring a value of a signal characteristic, such as signal-to-noise ratio, of two signals with different sets of weighting factors, and determining an adjustment factor to the radial tilt as a function of the of the measured signal characteristic values.