Abstract: Systems and method relating generally to data processing, and more particularly to systems and methods for utilizing multiple data streams for data recovery from a storage device.

Abstract: Systems and method relating generally to data processing, and more particularly to systems and methods for utilizing multiple data streams for data recovery from a storage device.

Abstract: A magnetic recording system includes an array of analog inputs operable to receive analog signals retrieved from a magnetic storage medium, a modulator operable to combine the analog signals to yield a frequency division multiplexed signal, a demodulator operable to yield a plurality of demodulated signals from the frequency division multiplexed signal corresponding to each channel of the array, and a joint equalizer operable to filter the plurality of demodulated signals to yield an equalized output.

Abstract: A magnetic recording system includes an array of analog inputs operable to receive an array of analog signals retrieved from a magnetic storage medium, where one of the array of analog signals corresponds with a reference channel, a timing recovery circuit operable to generate a clock signal based on the analog signal for the reference channel, a number of analog to digital converters each operable to sample one of the array of analog signals based on the clock signal to yield a number of digital channels, and a joint equalizer operable to filter the digital channels to yield an equalized output.

Abstract: A magnetic recording system includes an array of analog inputs operable to receive an array of analog signals retrieved from a magnetic storage medium, where one of the array of analog signals corresponds with a reference channel, a timing recovery circuit operable to generate a clock signal based on the analog signal for the reference channel, a number of analog to digital converters each operable to sample one of the array of analog signals based on the clock signal to yield a number of digital channels, and a joint equalizer operable to filter the digital channels to yield an equalized output.

Abstract: A magnetic recording system includes an array of analog inputs operable to receive analog signals retrieved from a magnetic storage medium, a modulator operable to combine the analog signals to yield a frequency division multiplexed signal, a demodulator operable to yield a plurality of demodulated signals from the frequency division multiplexed signal corresponding to each channel of the array, and a joint equalizer operable to filter the plurality of demodulated signals to yield an equalized output.

Abstract: First and second apparent resistance measures are determined for an integrated circuit and utilized to characterize the integrated circuit. The first apparent resistance measure is determined for the integrated circuit based on a first voltage drop and a first current that are measured using test equipment. The second apparent resistance measure is determined for the integrated circuit based on a second voltage drop and a second current that are obtained using static analysis of a corresponding integrated circuit design. The integrated circuit is characterized based on a comparison of the first and second apparent resistance measures. For example, characterizing the integrated circuit may comprise validating the static analysis of the integrated circuit design based on the comparison of the first and second apparent resistance measures, or determining a quality measure of the integrated circuit based on the comparison of the first and second apparent resistance measures.

Abstract: An apparatus comprises read channel circuitry and associated signal processing circuitry comprising frontend processing circuitry and backend processing circuitry. The frontend processing circuitry comprises a loop detector and equalizer configured to determine an equalized read channel signal from a read channel signal and a decoding module configured to apply verification and scrambling processing on a decoded read channel signal. The backend processing circuitry comprises a backend detector, an interleaver, a backend decoder, and a de-interleaver configured to perform an iterative decoding process on the equalized read channel signal to determine the decoded read channel signal. The frontend processing circuitry is controlled by a first clock having an associated first clock rate and the backend processing circuitry is controlled by a selected one of the first clock and a second clock having an associated second clock rate determined at least in part by the first clock rate and a maximum clock rate.

Abstract: An apparatus comprises read channel circuitry and associated signal processing circuitry comprising frontend processing circuitry and backend processing circuitry. The frontend processing circuitry comprises a loop detector and equalizer configured to determine an equalized read channel signal from a read channel signal and a decoding module configured to apply verification and scrambling processing on a decoded read channel signal. The backend processing circuitry comprises a backend detector, an interleaver, a backend decoder, and a de-interleaver configured to perform an iterative decoding process on the equalized read channel signal to determine the decoded read channel signal. The frontend processing circuitry is controlled by a first clock having an associated first clock rate and the backend processing circuitry is controlled by a selected one of the first clock and a second clock having an associated second clock rate determined at least in part by the first clock rate and a maximum clock rate.

Abstract: First and second apparent resistance measures are determined for an integrated circuit and utilized to characterize the integrated circuit. The first apparent resistance measure is determined for the integrated circuit based on a first voltage drop and a first current that are measured using test equipment. The second apparent resistance measure is determined for the integrated circuit based on a second voltage drop and a second current that are obtained using static analysis of a corresponding integrated circuit design. The integrated circuit is characterized based on a comparison of the first and second apparent resistance measures. For example, characterizing the integrated circuit may comprise validating the static analysis of the integrated circuit design based on the comparison of the first and second apparent resistance measures, or determining a quality measure of the integrated circuit based on the comparison of the first and second apparent resistance measures.

Abstract: Various embodiments of the present invention provide systems and methods for phase compensated harmonic sensing. For example, a circuit for harmonics calculation is disclosed that includes a phase difference estimation circuit and a phase offset compensation circuit. The harmonic calculation circuit is operable to calculate a first harmonic based on a periodic data pattern and a second harmonic based on the periodic data pattern. The phase difference estimation circuit operable to calculate a phase difference between the first harmonic and the second harmonic. The phase offset compensation circuit operable to align the second harmonic with the first harmonic to yield an aligned harmonic.

Abstract: Various embodiments of the present invention provide systems and methods for servo data based harmonics calculation. For example, a method for calculating harmonics is disclosed that includes: providing a data processing circuit; receiving a first data set derived from a data source during a servo data processing period; performing a first harmonics calculation using the first data set to yield a first harmonics ratio; receiving a second data set derived from a source other than the previously mentioned data source during a user data processing period; performing a second harmonics calculation using the second data set to yield a second harmonics ratio; and calculating a ratio of the first harmonics ratio to the second harmonics ratio.

Abstract: Various embodiments of the present invention provide systems and methods for phase compensated harmonic sensing. For example, a circuit for harmonics calculation is disclosed that includes a phase difference estimation circuit and a phase offset compensation circuit. The harmonic calculation circuit is operable to calculate a first harmonic based on a periodic data pattern and a second harmonic based on the periodic data pattern. The phase difference estimation circuit operable to calculate a phase difference between the first harmonic and the second harmonic. The phase offset compensation circuit operable to align the second harmonic with the first harmonic to yield an aligned harmonic.

Abstract: Various embodiments of the present invention provide systems and methods for servo data based harmonics calculation. For example, a method for calculating harmonics is disclosed that includes: providing a data processing circuit; receiving a first data set derived from a data source during a servo data processing period; performing a first harmonics calculation using the first data set to yield a first harmonics ratio; receiving a second data set derived from a source other than the previously mentioned data source during a user data processing period; performing a second harmonics calculation using the second data set to yield a second harmonics ratio; and calculating a ratio of the first harmonics ratio to the second harmonics ratio.

Abstract: A folded cascode device senses the drain current of a source follower, and a current mirror device multiplies the sensed drain current for application to an output load. The source follower and the current mirror device are preferably of the same type (e.g., both NMOS). The resulting composite source follower provides relatively wide bandwidth at relatively low power. The folded cascode allows (NMOS) source and sink control. Using current mirror feedback reduces the stability problems associated with other solutions that rely on a voltage feedback stage. Composite source followers of the present invention can be used in any traditional buffer applications, such as in operational amplifiers, regulators, or high-speed signal paths.

Abstract: A folded cascode device senses the drain current of a source follower, and a current mirror device multiplies the sensed drain current for application to an output load. The source follower and the current mirror device are preferably of the same type (e.g., both NMOS). The resulting composite source follower provides relatively wide bandwidth at relatively low power. The folded cascode allows (NMOS) source and sink control. Using current mirror feedback reduces the stability problems associated with other solutions that rely on a voltage feedback stage. Composite source followers of the present invention can be used in any traditional buffer applications, such as in operational amplifiers, regulators, or high-speed signal paths.

Abstract: An integrated circuit includes a self-calibrating resistor circuit comprising a resistor string, a comparator, a state machine, a reference voltage source, and a reference current source. The current source typically comprises a voltage reference, typically a bandgap reference, and a temperature-independent resistor having a value REXT. In operation, a reference current IREF flows through the resistor string. During a calibration period, the voltage across the string is compared to the bandgap reference voltage, VBG, by the comparator, which controls the state of the state machine. The outputs of the state machine turn on or off the resistors in the string until the voltage across the string, VR, is approximately equal to the reference voltage. The resistance of the resistor string is then equal to RBG=VBG/IREF, which is proportional to REXT, and thus is typically independent of process and temperature.

Abstract: Briefly, in accordance with one embodiment of the invention, a circuit includes: at least one differential amplifier. The differential amplifier is coupled in a circuit configuration so that the differential output voltage signal of the differential amplifier circuit includes a scalable second-order harmonic component of the differential input voltage signal applied to the differential amplifier circuit. Briefly, in accordance with another embodiment of the invention, a method of applying a differential input voltage signal to a differential amplifier circuit to produce a differential output voltage signal includes the step of: driving the differential amplifier circuit so that the differential output voltage signal of the differential amplifier circuit includes a second-order harmonic component of the differential input voltage signal.