Abstract: Various embodiments of the present invention provide systems and methods for data processing. As an example, a data processing circuit having a data detection circuit is disclosed that includes: a scaling circuit, a soft output calculation circuit, and a factor calculation circuit. The scaling circuit is operable to scale a branch metric value by a scaling factor to yield a scaled output. The soft output calculation circuit is operable to calculate a soft output based at least in part on the scaled output. The factor calculation circuit operable to modify the scaling factor based at least in part on the soft output.

Abstract: The present invention is a device for detecting short burst errors. The device includes a first signal input, wherein the first signal input is configured to receive a first signal. The device includes a second signal input, wherein the second signal input is configured to receive a second signal. The device includes a logic gate, wherein the logic gat is operable for receiving the first signal vial the first signal input, receiving the second signal via the second signal input, and generating a logic output gate signal based on the received first signal and the second signal. Furthermore, the device includes a filter, wherein the filter is configured for receiving the logic output gate signal from the logic gate and generates a filter output signal based upon the received logic output gate signal, wherein the filter output signal is operable for flagging errors.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. For example, a data processing circuit is disclosed that includes a first data detection circuit that applies a phase dependent data detection algorithm to a data set such that a first output of the first data detection circuit varies depending upon a phase of the data set presented to the first data detection circuit. A first phase of the data set is presented to the first data detection circuit. The circuits further include a decoder circuit that applies a decoding algorithm to the first output to yield a decoded output, and a phase shift circuit that phase shifts the decoded output such that a second phase of the data set is provided as a phase shifted output.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. As an example, a data processing circuit is disclosed that includes an equalizer circuit and a data detection circuit. The equalizer circuit is operable to filter a series of samples based at least in part on a filter coefficient and to provide a corresponding series of filtered samples. The data detection circuit includes: a core data detector circuit and a coefficient determination circuit. The core data detector circuit is operable to perform a data detection process on the series of filtered samples and to provide a most likely path and a next most likely path. The coefficient determination circuit operable to update the filter coefficient based at least in part on the most likely path and the next most likely path.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. For example, a variable iteration data processing system is disclosed that includes at least a first detector, a second detector, a decoder, and a queuing buffer. The first detector is operable to perform a data detection on an input data set at a first time. The decoder receives a derivation of an output from the first detector and performs a decoding process. Where the decoding process fails to converge, the decoder output is passed to the second detector for a subsequent detection and decoding process at a second time.

Abstract: Various embodiments of the present invention provide systems and methods for detecting storage medium defects. As one example, a media defect detection system is disclosed that includes a data detector circuit that applies a detection algorithm to the data input and provides a hard output and a soft output. A first circuit combines a first derivative of the hard output with a derivative of the data input to yield a first combined signal. A second circuit combines a second derivative of the hard output with a derivative of the first combined signal to yield a second combined signal. A third circuit combines a derivative of the soft output with the second combined signal and a threshold value to yield a defect signal.

Abstract: In exemplary embodiments, a skewed interleaving function for iterative code systems is described. The skewed interleaving function provides a skewed row and column memory partition and a layered structure for re-arranging data samples read from, for example, a first channel detector. An iterative decoder, such as an iterative decoder based on a low-density parity-check code (LDPC), might employ an element to de-skew the data from the interleaved memory partition before performing iterative decoding of the data, and then re-skew the information before passing decoded samples to the de-interleaver. The de-interleaver re-arranges the iterative decoded data samples in accordance with an inverse of the interleaver function before passing the decoded data samples to, for example, a second channel detector.

Abstract: The present invention is a device for detecting short burst errors. The device includes a first signal input, wherein the first signal input is configured to receive a first signal. The device includes a second signal input, wherein the second signal input is configured to receive a second signal. The device includes a logic gate, wherein the logic gate is operable for receiving the first signal vial the first signal input, receiving the second signal via the second signal input, and generating a logic output gate signal based on the received first signal and the second signal. Furthermore, the device includes a filter, wherein the filter is configured for receiving the logic output gate signal from the logic gate and generates a filter output signal based upon the received logic output gate signal, wherein the filter output signal is operable for flagging errors.

Abstract: Various embodiments of the present invention provide systems and methods for flaw scan in a data processing system. As one example, a data processing system is disclosed that includes a data detector circuit, a bit sign inverting circuit, and an LDPC decoder circuit. The data detector circuit receives a verification data set that is an invalid LDPC codeword, and applies a data detection algorithm to the verification data set to yield a detected output. The bit sign inverting circuit modifies the sign of one or more elements of a first derivative of the detected output to yield a second derivative of the detected output. The second derivative of the detected output is an expected valid LDPC codeword. The LDPC decoder circuit applies a decoding algorithm to the second derivative of the detected output to yield a decoded output.

Abstract: A system, method, and device for detecting short burst errors in a queue-based system is disclosed. A first detector performs a data detection on a first input data set at a first time and on a second input data set at a second time. A second detector performs a data re-detection on input data sets. A decoder decodes derivations of the outputs of the first and second detector. A short burst error detector may perform a short burst error detection on decoded data and erase any detected errors. An output data buffer stores and orders the decoded data for output.

Abstract: Various embodiments of the present invention provide systems and methods for data processing retries. As an example, a data processing retry circuit is discussed that includes a stepped erasure window register, and an erasure flag set circuit. The stepped erasure window register includes: an erasure flag location, an erasure flag length, and a step size. The erasure flag set circuit is operable to assert a first erasure flag beginning at the erasure flag location and having the erasure flag length at a first time. In addition, the erasure flag set circuit is operable to assert a second erasure flag beginning at the erasure flag location plus the step size, and having the erasure flag length at a second time.

Abstract: Various embodiments of the present invention provide systems and methods for data regeneration. For example, a system for data regeneration is disclosed that includes a data input derived from the medium. A data detector and a data recovery system receive the data input. The data detector provides a first soft output, and the data recovery system provides a second soft output. The first soft output and the second soft output are provided to a multiplexer. A media defect detector performs a media defect detection process, and provides a defect flag that indicates whether the data input is derived from a defective portion of the medium. The defect flag is provided to the multiplexer where it is used to select whether the first soft output or the second soft output is provides as an extrinsic output.

Abstract: Various embodiments of the present invention provide systems and methods for sync mark detection. As an example, a sync mark detection circuit is discussed that includes a storage circuit, a plurality of noise predictive filter circuits, and a controller circuit. The storage circuit is operable to store a data input as a stored input. The plurality of noise predictive filters are operable to receive a processing input. At least one of the noise predictive filters is selectably modifiable to either increase the probability of finding a sync mark in the processing input or to maintain a baseline probability of finding the sync mark in the processing input. The controller circuit is operable to determine an operational mode that may be a standard operational mode, a bit flipping mode, or a filter modification mode.

Abstract: Various embodiments of the present invention provide systems and methods for data regeneration. For example, a method for data regeneration is disclosed that includes receiving a data input derived from a medium, determining a media defect corresponding to the data input, and determining an attenuation factor associated with the defective medium. Based at least in part on the determination that the medium is defective, amplifying the data input by a derivative of the attenuation factor to regenerate the data.

Abstract: Various embodiments of the present invention provide systems and methods for media defect detection. For example, a media defect detection systems is disclosed that includes a data input derived from a medium, a fast envelope calculation circuit that receives the data input and provides a fast decay envelope value based on the data input, a slow envelope calculation circuit that receives the data input and provides a slow decay envelope value based on the data input, and a media defect detection circuit. The media defect detection circuit receives the slow decay envelope value and the fast decay envelope value, calculates a ratio value of the fast decay envelope value to the slow decay envelope value, and asserts a defect output based at least in part on the comparison of the ratio value to a defect threshold value.

Abstract: Various embodiments of the present invention provide systems and methods for media defect detection. For example, a data receiving system is disclosed that includes a data signal provided from a medium that may include a defective portion. An absolute value circuit receives the data signal and provides an output corresponding to an absolute value of the data signal. The output corresponding to the absolute value of the data signal is input to a filter that filters it and provides a filtered output. In some cases, the filter is a digital filter operable to integrate the absolute value of the data signal. A comparator receives the output from the filter and compares it with a threshold value. The result of the comparison indicates a defect status of the medium.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. For example, a data processing system is disclosed that includes a decoder circuit providing a decoded output, and a dynamic scalar calculation circuit that determines a first dynamic scaling value and a second dynamic scaling value based at least in part on the decoded output. A first multiplier circuit multiplies the decoded output by the first dynamic scaling value and provides a first scaled output. A detector circuit receives the first scaled output and provides a detected output. A second multiplier circuit multiplies the detected output by the second dynamic scaling value and provides a second scaled output.

Abstract: Various embodiments of the present invention provide systems and methods for data regeneration. For example, a system for data regeneration is disclosed that includes a data input derived from the medium. A data detector and a data recovery system receive the data input. The data detector provides a first soft output, and the data recovery system provides a second soft output. The first soft output and the second soft output are provided to a multiplexer. A media defect detector performs a media defect detection process, and provides a defect flag that indicates whether the data input is derived form a defective portion of the medium. The defect flag is provided to the multiplexer where it is used to select whether the first soft output or the second soft output is provides as an extrinsic output.

Abstract: In a hard-disc drive, a defect region on the hard disc is detected by generating two statistical measures (e.g., ?1(k) and ?2(k)) based on signal values (e.g., x[n] or y[n]) and soft-decision values (e.g., L[n]) corresponding to the signal values. The measures are compared to detect the location of the defect region of the hard drive. Using the soft-decision values reduces fluctuations in a ratio of the statistical measures compared to a ratio formed from statistical measures that are not based on soft-decision values, resulting in a more-reliable test for detecting defect regions.

Abstract: Certain embodiments of the present invention are improved turbo-equalization methods for decoding encoded codewords. In one embodiment, in global decoding iteration i, the magnitude values of all decoder-input LLR values (Lch) are adjusted based on the number b of unsatisfied check nodes in the decoded codeword produced by global iteration i?1. The improved turbo-equalization methods can be used as the sole turbo-equalization method for a given global decoding session, or interleaved with other turbo-equalization methods.