Abstract: In various embodiments, systems and methods to detect signal irregularity caused by defects in the read/write head element are disclosed. In some embodiments, an exemplary system comprises a memory and a processor. The processor is coupled to the memory and is configured to implement a filter module and a detector module. The filter module is configured to generate a test waveform based on data read from a medium by a storage device head to be tested. The detector module is configured to generate a signal quality value based on a property of at least a portion of the test waveform, compare the signal quality value to an event threshold, and generate an event indicator based on the comparison, the event indicator indicating possible instability of the storage device head.

Abstract: A decoding system includes a timing loop for use in error recovery mode operations, in which “fast decode” bit values that are used for timing recovery purposes in the normal modes of operation are replaced, at an appropriate iteration in the error recovery mode, with detected bit values from an iterative detector. The replacement occurs after a reread operation in which the timing loop maintains lock.

Abstract: Methods are disclosed for detecting a thermal asperity condition of a head that is configured to generate a read signal by reading data on a rotatable data storage disk in a disk drive. The read signal includes a data component and a thermal component. The read signal is compared to a thermal asperity threshold to detect occurrence of an excessive level of the thermal component of the read signal as a thermal asperity condition of the head. The thermal asperity threshold is varied in response to a rate of occurrence of data value transitions in the data component of the read signal. The thermal asperity threshold can be increased in response to a decrease in the rate of occurrence of data value transitions, and can be decreased in response to an increase in the rate of occurrence of data value transitions. By varying the thermal asperity threshold, the sensitivity of the thermal asperity detector may be improved to allow lower level thermal asperity conditions to be detected with increased accuracy.

Abstract: Methods of compensating for radial incoherence in servo information that is read from adjacent servo tracks that have a phase offset relative to one another on a data storage disk of a disk drive are provided. While a transducer is seeking to a target track, the transducer generate a servo information signal that has a first component from servo information read from a first servo track on the disk and a second component from servo information read from a second servo track that is radially adjacent to the first servo track. The servo information in the first and second servo tracks are offset by a non-zero phase error relative to one another and are in a same servo sector on the disk. The servo information signal is sampled to generate a series of sampled servo values. A phase error of a group of the sampled servo values is determined. The sampled servo values are compensated in response to the determined phase error to generate compensated servo values with at least reduced phase error.

Abstract: Automatic control and fuel saving means for internal combustion engines, comprising: at least one centrifugal speed sensor having at least one pair of flyweights, which flyweights are disposed in the guide tracks on a holder, the said guide tracks are such orientated that the components of the centrifugal forces of the flyweights in the guide track directions substantially match the elastic forces of the spring exerting on the flyweights; a mode shifting device connected to the said speed sensor and to the manual operating mechanisms, the said mode shifting device alternately puts the engine into the automatic control mode by the said speed sensor or into the manual control mode.