Abstract: A acoustic damping pad is provided. The acoustic damping pad includes a first surface and an opposing second surface that are defined by a periphery. A first set of perforations extend between the first surface and the second surface of the acoustic damping pad. Each adjacent perforation in the first set of perforations is uniformly spaced apart from each other across a first select surface area of the first surface and across a corresponding first select surface area of the opposing second surface to form a uniform pattern.

Abstract: A disc clamp is provided for securing discs to a spindle motor. In particular, the clamp is useful in providing distributed forces to the discs. The clamp includes an annular body having an upper surface, a lower surface, an inner circumference and an outer circumference. A flange extends from the lower surface of the annular body and has an inner surface oriented towards the inner circumference of the annular body. A plurality of apertures are formed between the upper and lower surfaces of the annular body and are configured to receive fasteners. Further, a plurality of force distributing features are formed in the flange between the outer surface of the flange and the inner surface of the flange.

Abstract: A acoustic damping pad is provided. The acoustic damping pad includes a first surface and an opposing second surface that are defined by a periphery. A first set of perforations extend between the first surface and the second surface of the acoustic damping pad. Each adjacent perforation in the first set of perforations is uniformly spaced apart from each other across a first select surface area of the first surface and across a corresponding first select surface area of the opposing second surface to form a uniform pattern.

Abstract: A magnetic disk drive data storage disk defines recording tracks divided into data sectors by narrow servo spokes. A data sector lying between servo spokes is recorded with user data encoded in accordance with a code having a predetermined distance and user data code rate. Each servo spoke of the recording area has at least one servo information field encoded in a wide bi-phase code pattern. The disk drive further includes a synchronous sampling data detection channel having a data transducer head positioned by a servo-controlled actuator over the recording track, a preamplifier for receiving electrical analog signals magnetically induced by the data transducer head from flux transitions present in at least the servo information field, a digital sampler for synchronously sampling the electrical analog signals to produce digital samples, and wide bi-phase decoding circuitry coupled to receive digital samples from the synchronous sampling data detection channel for decoding the wide bi-phase code pattern.

Abstract: A magnetic disk drive data storage disk defines recording tracks divided into data sectors by narrow servo spokes. A data sector lying between servo spokes is recorded with user data encoded in accordance with a code having a predetermined distance and user data code rate. Each servo spoke of the recording area has at least one servo information field encoded in a wide bi-phase code pattern. The disk drive further includes a synchronous sampling data detection channel having a data transducer head positioned by a servo-controlled actuator over the recording track, a preamplifier for receiving electrical analog signals magnetically induced by the data transducer head from flux transitions present in at least the servo information field, a digital sampler for synchronously sampling the electrical analog signals to produce digital samples, and wide bi-phase decoding circuitry coupled to receive digital samples from the synchronous sampling data detection channel for decoding the wide bi-phase code pattern.

Abstract: Disclosed is a method and apparatus for increasing the reliability of a disk drive. A block of information is read from a storage medium to provide a first sample, which is stored. The method determines whether an uncorrectable error occurred during the reading, and when the error is determined to have occurred, the block of information is reread from the storage medium to provide an averaged sample, and the average sample is decoded. Further disclosed is a storage unit, which includes a reader for reading a block of information from a storage medium to provide a first sample and for storing said first sample. An error determining mechanism determines whether an uncorrectable error occurred during the reading and issues a command to the reader to re-read the block of information to provide a second sample when the uncorrectable error is determined. A processor receives and averages the first sample and the second sample and produces an averaged sample. A decoder decodes the average sample.

Abstract: A magnetic disk drive data storage disk defines recording tracks divided into data sectors by narrow servo spokes. A data sector lying between servo spokes is recorded with user data encoded in accordance with a code having a predetermined distance and user data code rate. Each servo spoke of the recording area has at least one servo information field encoded in a wide bi-phase code pattern. The disk drive further includes a synchronous sampling data detection channel having a data transducer head positioned by a servo-controlled actuator over the recording track, a preamplifier for receiving electrical analog signals magnetically induced by the data transducer head from flux transitions present in at least the servo information field, a digital sampler for synchronously sampling the electrical analog signals to produce digital samples, and wide bi-phase decoding circuitry coupled to receive digital samples from the synchronous sampling data detection channel for decoding the wide bi-phase code pattern.

Abstract: Methods and circuitry for generating sector and data cell timing frequencies for banded variable frequency sector disc drive systems with dedicated plus embedded servo positioning systems which have the timing signals synchronized to servo track information written on a dedicated surface of the disc.

Abstract: A multi-band processing system for automatically tuning the oscillator of a phase-locked loop to the frequency and phase of an applied input. The system includes an error detection circuit, a frequency controller, a scaling circuit, and a phase and frequency controller. The applied input and the oscillator output are coupled to the error detection circuit whose error output drives a charge pump/filter circuit. An error signal is derived from the difference between the loop charge pump output V.sub.1 and a preset charge pump zero error reference signal V.sub.ref, wherein the frequency controller regulates the oscillator output frequency according to a frequency error component of V.sub.1 -V.sub.ref, the scaling circuit scales the oscillator output frequency according to a system scaling signal N, and the phase and frequency controller adjusts the oscillator output frequency and phase according to V.sub.1 -V.sub.

Abstract: A disk drive system provides all required synchronization, positioning, validation, and data functions within each disk sector. All of these functions are provided within two zones, a header section and a data section. The header section includes a preamble, a synchronization character and an address field, as well as servo information for track following. The data section of each sector includes a data preamble, a data synchronization character, a bad sector bit map, the data and data redundancy information. The header section of at least one sector in a track includes a short DC-erase field, a transitionless segment which is used in synchronization. To synchronize a read/write head to the disk, the system first detects the DC-erase field. The system next searches for the header premable and synchronization character. If it finds them within predetermined times, it then looks for a valid sector address to complete the synchronization.

Abstract: A method and apparatus for combining a plurality of different filtering paths of varying bandwidth to provide selectable bandwidth signal filtering without transients caused by initialization of filter components. The signal to be filtered is applied to a plurality of parallel connected passband filters ranging from a widest passband filter to a narrowest passband filter. The bandwidth of the parallel filter combination is progressively narrowed by sequentially holding the output level of each of the filters in declining order of their passband frequency range, beginning with the widest passband filter, until all of the output levels of the filters are held constant except for the narrowest passband filter. This filter system is especially adapted for use as a loop filter in a phase locked loop control system incorporated in a data storage disc drive.

Abstract: A servo circuit for electronically controlling the operation of an electric motor is disclosed. The rotational frequency of the motor is converted into a varying frequency waveform by a tachometer. The tachometer output is applied to a conversion circuit which includes a peak detector that converts the output waveform of the tachometer into a square-wave signal. The square-wave signal is, in turn, connected to one input of an exclusive-OR gate. The peak detector square-wave signal is also applied to a shift register which, after a time delay, applies the same signal to another input of the exclusive-OR gate. With these connections, the exclusive-OR gate produces a square-wave output whose duty cycle is proportional to the speed of the DC motor. This output can then be either amplified and applied directly to the electric motor to drive it, or integrated and applied to an amplifier to drive the motor in accordance with standard servo techniques.

Abstract: A positioning system for a magnetic tape system that utilizes a multiple record recording format wherein positioning data that marks the beginning of record segments, the beginning of the tape medium, and the ending of the tape medium are pre-recorded at one-fourth of the bit density of work data so that positioning data may be more accurately read at a higher tape speed during a record seek mode of operation. The system also includes detector circuitry that is enabled only upon detecting positioning data and that identifies the positioning data as an inter-record mark signal, beginning of tape signal, or an ending of tape signal. A tape drive controller is responsive to the detection circuitry for controlling the speed and direction of the magnetic tape.