Abstract: A handheld portable battery powered digital antenna and/or network analyzer which derives complex impedance values at a given frequency includes an internal direct digital synthesis generator and provides software-defined multiple operating modes and real time graphic scalar and polar displays of results in a multiplicity of user-selectable visual formats.

Abstract: An improved molding apparatus and method includes an adjustable mold component and a fixed mold component for molding precision articles; a bias force mechanism for applying a bias force to the adjustable mold component; and an adjustable mold component fine position adjustment mechanism operable exteriorly of the mold for applying a position adjustment force to the adjustable mold component to overcome the bias force and thereby adjust position of the adjustable mold component relative to a fixed mold component to reduce positional offset in a range of ±ten microns, or less, in at least one adjustment dimension. In one aspect, a plurality of bias force mechanisms and adjustment mechanisms provide positional adjustment in a plurality of adjustment dimensions. In another aspect, a feedback control loop responsive to optically sensed positional error automatically reduces positional offset.

Abstract: A floating head for magnetic tape includes a longitudinal raised mesa and side wings and has a mesa major dimension less than a width of the tape without outriggers and employs a minimized tape wrap angle. The head may be rotated between operating positions for longitudinal track patterns and azimuthal track patterns. In one preferred form, the head is employed as a read-only head within a secondary head positioning mechanism included for backward compatibility within a high track density tape unit for reading longitudinal and azimuth track patterns recorded in accordance with earlier tape track standards.

Abstract: A magnetic tape head tilting mechanism for tilting the magnetic head to a desired azimuth angle. The azimuth tilting mechanism uses a worm gear and worm, driven by a stepper motor, which automatically adjusts the position of the magnetic head during recording of the signal onto the tape by the write head gap to maintain the strongest signal that is received by the read head gap. The fine angular resolution enables writing very high track densities and providing strong read signals.

Abstract: An objective-solid immersion lens assembly includes a unitary solid immersion lens body having an optical axis, an evanescent wave-conducting region along the optical axis, and a substantially spherical surface portion surrounding the optical axis oppositely the wave emitting region. A discrete objective lens is attached to, or otherwise formned at, the solid immersion lens body at the substantially spherical surface portion to be in alignment with the optical axis. Several manufacturing methods for making an air bearing slider including the objective-solid immersion lens assembly are disclosed.

Abstract: A single analog filter structure within a partial response channel combines an antialias low pass filter and a time domain waveform shaping equalizer upstream of a digital sampler. The filter also improves latencies associated with timing acquisition of a sampler clock generator loop by removing the latency of a separate equalization filter. The filter also provides a method for adapting a combination of internal filter state voltages and currents in real time for optimizing pole locations of the analog filter structure, during both data and timing recovery operations of the channel.

Abstract: A hard disk drive includes a spindle motor flex circuit having a connection end secured to a drive base at a location established by a reference feature and an actuator flex circuit having a connection end also secured to the base at the location established by the feature; a cover and cover gasket mounted to the base plate enclose and seal a rotating data storage disk, a disk spindle motor, a magnet structure, a rotary actuator assembly and the flex circuits except for the spindle motor connection end and the actuator connection end; and, a printed circuit board carrying drive electronics has a connector array of pressure pins aligned to contact facing connecting pads of the flex circuits, the connector array having an alignment pin for registering with the reference feature of the base plate as the printed circuit board is mounted to the base plate externally of the cover, thereby establishing electrical connections between the printed circuit board and the flex circuit connection pads.

Abstract: A method corrects track misregistration attributable to out-of-plane motions of a rotating disk in a hard disk drive, and includes the steps of measuring a base plate-roll-bias angle between the rotating data storage disk and the head arm with a precision measuring device, and connecting the head arm and load beam at a roll-bias angle selected to minimize track misregistration attributable to the roll-bias. A number of connection arrangements and structures are presented in order to achieve the desired reduction in track misregistration.

Abstract: Magnetic noise cancellation in a single-ended MR preamplifier front end is achieved by forming a balanced ground return path in a flex circuit connecting an MR head to the front end of the preamplifier. The balanced ground return path introduces a noise current in the opposite direction of the original noise current as viewed at the signal input pins of the preamplifier chip. In this manner common mode rejection of the radiated noise component is restored in the single-ended MR preamplifier circuit arrangement.

Abstract: A driver circuit drives a digital signal onto a differential digital data transmission bus nominally biased to a negative data state during bus idle intervals by a weak negation bias current. The driver circuit overcomes the negation bias current during an active signaling sequence and comprises a signal current source and sink pair for selectively sourcing and sinking current onto positive and negative lines of the transmission bus in accordance with internally-supplied binary data levels during the active signaling sequence, and a bias override current source and sink pair for applying an override bias current to the positive and negative lines of the transmission line without interruption during the signaling sequence.

Abstract: A trace conductor array includes an electrically insulative support substrate and a plurality of electrical signal trace conductors formed along substantially parallel paths in a single layer on the substrate. The electrical signal trace conductors each have a plurality of spaced apart trace conductor segments. Passive electrical trace conductors are formed on the substrate in spaces between the spaced apart adjacent trace conductor segments, and are spaced apart and electrically isolated therefrom. The passive trace conductors generally follow a geometry of the spaced apart segments and thereby repel magnetic flux lines at higher frequencies and result in decoupling of the high frequency current-carrying conductor trace segments. A preferred application is for interconnecting a head and a preamplifier/drive circuit within a hard disk drive.

Abstract: A two-part tape cartridge locking mechanism for releasably locking a rotatable tape reel against rotation within a tape cartridge housing. A bias spring urges the tape reel against a major wall of the tape cartridge housing along an axis of rotation. A first part of the lock comprises a reel locking feature of the reel facing the major wall, and a housing locking feature of the major wall facing the reel locking feature, such that the reel locking feature engages the housing locking feature in a contact relationship when the tape reel is forced toward the major wall by the bias spring. A second part of the lock comprises a separately actuable reel lock mounted to the housing for holding the tape reel locking feature in the contact relationship with the housing locking feature until the reel lock is separately actuated away from the tape reel.

Abstract: A magnetic storage tape includes a plurality of spaced-apart servo reference patterns formed along a longitudinal reference axis. The patterns result in a predetermined pattern of coherent magnetic signal disturbances to magnetic tracks written and read across the patterns. The tape drive decodes the disturbance pattern into a position error signal. A tape drive head position servo iteratively adjusts lateral position of a magnetic head relative to the tape, based on sequentially developed position error signals in order to bring the head rapidly into precise alignment with the longitudinal reference axis. A method for forming the reference patterns into the tape with laser beam ablation is also disclosed.

Abstract: An architecture that utilizes the cross-check code associated with the error correction code in a data communications system as a data integrity code to protect data stored in a temporary storage buffer within a data channel. In a preferred embodiment, a cross-check encoder and comparison circuit is added to an interface circuit which receives data from a host processing system. Incoming host data is encoded to produce redundant information according to the same Reed-Solomon code implemented in the cross-check circuitry already provided in the data path to detect miscorrections by the error correction code. Cross-check redundancy generated by the interface cross-check encoder is appended to its associated data block in the block memory buffer. The integrity of the data blocks passing through the buffer is checked by utilizing the cross-check circuitry to regenerate the redundant cross-check bytes and then performing a comparison of the regenerated cross-check bytes with the cross-check bytes from the buffer.

Abstract: An aerodynamically powered release latch mechanism is provided for a fixed disk drive. A disk clamp for clamping a single data storage disk to a spindle hub comprises a centrifugal airflow pumping structure, such as radially and axially extending, generally L-shaped turboblades, for increasing the level of a vane deflecting airflow as the disk rotates. The vane deflecting airflow releases an aerodynamically released actuator latch mechanism.

Abstract: A head suspension has an integrated multi-layer trace conductor array for supporting and electrically interconnecting a read/write head to electronic circuitry in a disk drive. The electrical micro strip transmission line characteristics of the conductor array is controlled by the selective placement and connection of the trace paths within the multiple layers in order to control and balance electrical parameters including array inductance, inter-trace capacitance, and trace capacitance to a ground plane. The ground plane may further comprise a solid sheet of material or an arrangement of grounded traces disposed in proximity to signal-carrying traces of the micro strip transmission line in order to control and obtain desired electrical characteristics.

Abstract: A read-after-write head for four channel azimuth recording in one mode of operation and two channel non-azimuth recording in another mode of operation. Four forward write head gaps, four read head gaps, and four backward write head gaps are geometrically positioned within a rotatable and laterally indexable face plate of a recording head housing. The read and write heads gaps collectively provide four forward write channels, four read channels, and four backward write channels. During the azimuth mode of operation, the head is rotated to the preselected positive or negative azimuth angle and all of the read and write channels are utilized. During the non-azimuth, or vertical, mode of operation, write channels two and four are utilized in combination with read channels one and three to provide two-channel non-azimuth, or vertical, operation.

Abstract: A data channel, such as a magnetic recording/playback channel implements a time-varying maximum-transition-run code such that the code allows three consecutive transitions while it removes a dominant plus-minus-plus error-event and does not permit of four or more consecutive transitions.

Abstract: A method of adjusting the lateral position of writing on a magnetic tape. Alternate data and servo information is recorded in a first track at a first azimuth angle, the first track including a longitudinal gap such that the first track includes a first lateral portion and a second lateral portion. Alternate data and servo information is recorded in a second track at a second azimuth angle, the second track including a similar longitudinal gap, the second track being written over the first track such that the first portion of the first track remains on the tape. The gap in the second track is positioned such that the alternate data and servo information written in the second portion of the first track is exposed by the gap in the second track. Alternate data and servo information is similarly written in a third track at the first azimuth angle, the third track including a similar gap.

Abstract: An integrated circuit driver chip includes an on-board precision current reference source, a pull-up FET and a pull-down FET having a common node connected to a transmission line. A variable switching edge pre-driver drives at least one of the pull-up FET and pull-down FET in accordance with a push-pull fast edge mode and a wired-OR slow edge mode and includes a weak FET and a strong FET selectively connected in parallel with the weak FET to implement the push-pull fast edge mode while the weak FET operating alone implements the wired-OR slow edge mode. A switched current source selectively sources current through the pull-up FET to the transmission line in accordance with the data signal and includes a trickle current FET switch for maintaining charge stored on a parasitic capacitance when the pull-up FET is off thereby preventing current spikes during turn-on switching of the pull-up FET.