Abstract: Systems, methods, devices, circuits for data processing, and more particularly to systems and methods for data processing to identify a defect on a medium.

Abstract: A data detector includes a branch metric calculator operable to calculate branch metrics for transitions between states in a trellis for the data detector, and a pruning circuit operable to prune prohibited states from the trellis. The states in the trellis comprise basic states and extended states, where the extended states have a greater number of bits than the basic states.

Abstract: Systems, methods, devices, circuits for data processing, and more particularly to systems and methods for data processing to identify a defect on a medium.

Abstract: A data detector includes a branch metric calculator operable to calculate branch metrics for transitions between states in a trellis for the data detector, and a pruning circuit operable to prune prohibited states from the trellis. The states in the trellis comprise basic states and extended states, where the extended states have a greater number of bits than the basic states.

Abstract: The present inventions are related to systems and methods for data processing, and more particularly to systems and methods for data detection. As one example, a data processing system is described that includes a variance calculation circuit operable to calculate a variance of a data input; and a branch metric calculation circuit operable to calculate a branch metric based at least in part on the variance.

Abstract: A communication channel structure and a decoding method supported by such a communication channel structure are disclosed. Such a communication channel includes a digital filter configured for filtering an input signal and two quantizer configured for quantizing the filtered signal. A first quantizer is utilized to quantize the filtered signal to produce a first quantized sample having a first precision and a second quantizer is utilized to quantize the filtered signal to produce a second quantized sample having a second precision, wherein the second precision is different from the first precision. The communication channel also includes an iterative decoder configured for utilizing the first quantized sample for a first global iteration of a decoding process and utilizing the second quantized sample for at least one subsequent global iteration of the decoding process.

Abstract: A data dependent equalizer circuit includes a plurality of noise prediction filters. Respective ones of the noise prediction filters are configured to filter noise in sample data for at least one predetermined non-return to zero (NRZ) condition. A plurality of equalizers is communicatively coupled with the plurality of noise prediction filters. Respective ones of the plurality of equalizers are configured to yield equalized sample data that corresponds to the at least one predetermined NRZ condition for one or more of the noise prediction filters.

Abstract: Various systems and methods for media defect detection.

Abstract: An apparatus for calibrating a noise predictive filter includes a noise-predictive filter operable to filter digital data samples to yield filtered data samples, a calibration circuit operable to calculate tap coefficients for the noise-predictive filter based at least in part on the digital data samples, and a gating circuit operable to select a portion of the digital data samples for use by the calibration circuit in calculating the tap coefficients.

Abstract: A communication system and a noise predictive calibration method are disclosed. The communication system includes a decoder configured to decode an input signal, wherein the decoder produces one of: a converged data output when the decoder decodes the input signal successfully, and a non-converged data output when the decoder decodes the input signal unsuccessfully. The communication system also includes a convergence monitor configured to determine a calibration procedure based on at least one of: a number of times where the decoder decodes successfully, and a number of times where the decoder decodes unsuccessfully. A noise predictive calibration circuit is configured to utilize output produced by the decoder without qualification when the convergence monitor indicates utilization of a first calibration procedure.

Abstract: The present invention is a programmable QC LDPC encoder for encoding user data. The encoder may be configurable for implementation with a read channel. The encoder may include a plurality of barrel shifter circuits. The barrel shifter circuits are configured for generating a plurality of parity bits based on interleaved user bits received by the encoder. The barrel shifter circuits are further configured for outputting the parity bits. The encoder may further include an encoder interleaver memory. The encoder interleaver memory may be communicatively coupled with the barrel shifter circuits and may receive the parity bits output from the barrel shifter circuits. The encoder interleaver may be configured for interleaving the parity bits. Further, the encoder may be configured for outputting the interleaved parity bits to a multiplexer. The barrel shifter circuits may generate the plurality of parity bits via an encoding algorithm: p=u*GT.

Abstract: A communication system and a noise predictive calibration method are disclosed. The communication system includes a decoder configured to decode an input signal, wherein the decoder produces one of: a converged data output when the decoder decodes the input signal successfully, and a non-converged data output when the decoder decodes the input signal unsuccessfully. The communication system also includes a convergence monitor configured to determine a calibration procedure based on at least one of: a number of times where the decoder decodes successfully, and a number of times where the decoder decodes unsuccessfully. A noise predictive calibration circuit is configured to utilize output produced by the decoder without qualification when the convergence monitor indicates utilization of a first calibration procedure.

Abstract: The present inventions are related to systems and methods for data processing, and more particularly to systems and methods for coasting one or more calibration loops based upon identification of a probability of data inaccuracies. One embodiment is a data processing system that includes: a defect detector circuit operable to identify a defect region during a first pass processing of a received data set; a defect location buffer operable to maintain an indication of the defect region in the received data set; and a calibration circuit operable to adaptively update a calibration output during a second pass processing of the received data set, where updating the calibration output is disabled for one or more samples of the received data set corresponding to the indication of the defect region.

Abstract: Various embodiments of the present invention provide systems and methods for media defect detection. As an example, a method is discusses that includes: receiving a decoded output including a first multi-bit symbol; receiving a detected output including a second multi-bit bit symbol; calculating values based upon respective combinations of the first multi-bit symbol and the second multi-bit symbols; calculating a first product and the second product based upon some of the aforementioned values; and asserting a suspect symbol indicator indicating a probability that the symbol is incorrect when at least one of the first product and the second product is negative.

Abstract: A communication channel structure and a decoding method supported by such a communication channel structure are disclosed. Such a communication channel includes a digital filter configured for filtering an input signal and two quantizer configured for quantizing the filtered signal. A first quantizer is utilized to quantize the filtered signal to produce a first quantized sample having a first precision and a second quantizer is utilized to quantize the filtered signal to produce a second quantized sample having a second precision, wherein the second precision is different from the first precision. The communication channel also includes an iterative decoder configured for utilizing the first quantized sample for a first global iteration of a decoding process and utilizing the second quantized sample for at least one subsequent global iteration of the decoding process.

Abstract: Aspects of the disclosure pertain to a system and method for providing dynamic y-buffer size adjustment for retained sector reprocessing (RSR). The system and method implement dynamic y-buffer size adjustment for RSR for promoting improved Sector Failure Rate (SFR) performance of the system. The system is a read channel system.

Abstract: Various systems and methods for media defect detection.

Abstract: The present inventions are related to systems and methods for data processing, and more particularly to systems and methods for variable rate encoding and/or decoding in a data processing system. In some cases, embodiments include a variable length data decoder circuit that is operable to apply a decode algorithm to the encoded input based upon a first selected H-Matrix to yield a first decoded output and apply the decode algorithm to the encoded input based upon a second selected H-Matrix to yield a second decoded output.

Abstract: Various embodiments of the present invention provide systems and methods for media defect detection.

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.