摘要:
Various embodiments of the present invention provide systems and methods for determining changes in fly-height. For example, various embodiments of the present invention provide storage devices that include a storage medium having servo data thereon. A read/write head assembly is disposed in relation to the storage medium. A servo based fly-height adjustment circuit receives the servo data via the read/write head assembly, and calculates a first harmonics ratio based on the received data and compares the first harmonics ratio with a second harmonics ratio to determine an error in the distance between the read/write head assembly and the storage medium.
摘要:
Various embodiments of the present invention provide systems and methods for estimating noise components in a received signal set. For example, one embodiment of the present invention provides a noise estimation circuit that includes a data detector circuit and a noise component calculation circuit. The data detector circuit receives a series of data samples and provides a detected output, and the noise component calculation circuit provides an electronics noise power output and a media noise power output each calculated based at least in part on the detected output and the series of data samples.
摘要:
In one embodiment, a hard-disk drive system performs fly-height control using a read-back mode and a loop-back mode. The read-back mode measures first and second harmonics pre-recorded on the medium and divides the first measurement by the second to obtain a read-back mode harmonic ratio. The loop-back mode measures the same first and second harmonics; however, the harmonics are provided by a write precompensation circuit rather than the medium. Further, the loop-back mode measurements are performed using asynchronous sampling to address aliasing and quantization errors. The first measurement is divided by the second to generate a loop-back harmonic ratio. In logarithm domain, the loop-back ratio is subtracted from the read-back mode ratio to remove environment-induced variations in the read path electronic circuits. The resulting harmonic ratio is subtracted from an initial harmonic ratio determined, for example, during manufacturing, to determine how much the harmonic ratio has changed.
摘要:
Various embodiments of the present invention provide systems and methods for adaptive channel bit density estimation. For example, various embodiments of the present invention provide methods for adaptively estimating channel bit density. Such methods include providing a storage medium (178) that includes information corresponding to a process data set, and accessing the process data set from the storage medium (505). A first channel bit density estimate (535) is computed based at least in part on a first portion of the process data set (520-530), and a second channel bit density estimate (535) is calculated based at least in part on the first portion of the process data set, a second portion of the process data set (520-530) and the first channel bit density estimate (535).
摘要:
Various embodiments of the present invention provide systems and methods for providing a corrected dibit signal. As an example, various embodiments of the present invention provide dibit correction circuits. Such dibit correction circuits include a dibit sample buffer, a maximum sample detector circuit, a side sample detector circuit, and a dibit correction circuit. The dibit sample buffer includes a plurality of samples of an uncorrected dibit signal. The maximum sample detector circuit identifies a maximum sample of the plurality of samples of the uncorrected dibit signal, and the side sample detector circuit identifies a first side sample prior to the maximum sample on the uncorrected dibit signal and a second side sample following the maximum sample on the uncorrected dibit signal. The dibit correction circuit applies a correction factor calculated based at least in part on the maximum sample, the first side sample and the second side sample to at least a subset of the plurality of samples of the uncorrected dibit signals to yield a plurality of corrected dibit signals.
摘要:
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.
摘要:
Various embodiments of the present invention provide systems and methods for adaptive channel bit density estimation. For example, various embodiments of the present invention provide methods for adaptively estimating channel bit density. Such methods include providing a storage medium (178) that includes information corresponding to a process data set, and accessing the process data set from the storage medium (505). A first channel bit density estimate (535) is computed based at least in part on a first portion of the process data set (520-530), and a second channel bit density estimate (535) is calculated based at least in part on the first portion of the process data set, a second portion of the process data set (520-530) and the first channel bit density estimate (535).
摘要:
In one embodiment, a storage-device-implemented method for estimating one or more channel parameters of a storage device including a read channel and a storage medium with a bit sequence stored on the storage medium. The method includes: (a) the storage device reading at least a portion of the bit sequence from the storage medium to generate a bit response; (b) the storage device convolving the bit response to compute an impulse response of the read channel; and (c) the storage device estimating one or more channel parameters based on the computed impulse response.
摘要:
In one embodiment, a hard-disk drive system performs fly-height control using a read-back mode and a loop-back mode. The read-back mode measures first and second harmonics pre-recorded on the medium and divides the first measurement by the second to obtain a read-back mode harmonic ratio. The loop-back mode measures the same first and second harmonics; however, the harmonics are provided by a write precompensation circuit rather than the medium. Further, the loop-back mode measurements are performed using asynchronous sampling to address aliasing and quantization errors. The first measurement is divided by the second to generate a loop-back harmonic ratio. In logarithm domain, the loop-back ratio is subtracted from the read-back mode ratio to remove environment-induced variations in the read path electronic circuits. The resulting harmonic ratio is subtracted from an initial harmonic ratio determined, for example, during manufacturing, to determine how much the harmonic ratio has changed.
摘要:
Various embodiments of the present invention provide systems and methods for estimating noise components in a received signal set. For example, one embodiment of the present invention provides a noise estimation circuit that includes a data detector circuit and a noise component calculation circuit. The data detector circuit receives a series of data samples and provides a detected output, and the noise component calculation circuit provides an electronics noise power output and a media noise power output each calculated based at least in part on the detected output and the series of data samples.