Abstract: A unitary cartridge, or module, provides a self-contained, high accuracy, ready-to-use assembly for controlling fine positioning of a head gimbal assembly (HGA) disposed on a head mounting unit mounted on the cartridge, with respect to a spinstand or other device associated with a head tester. In a form, the head-mounting unit and a counterweight element are configured to be moveable relative to the base in opposite directions along a displacement axis in response to actuators in the cartridge, and are operative in concert with a damping assembly configured to interact with the counterweight element and the heads mounting unit to mitigate vibrational movement of the cartridge.

Abstract: A piezoelectric actuator includes a housing body and lid wherein the housing body defines an open-ended cylindrical interior chamber extending along a displacement axis. The lid bolts to the body transverse to the open end allowing easy access to an electrostrictive assembly disposed within the chamber. The electrostrictive assembly includes an electrostrictive element affixed at one end to the housing by a cup element with an outermost cylindrical surface, and at an opposite, and free, end, to a driver having a portion with a outermost cylindrical surface. The outermost cylindrical surfaces both include circumferential sealing elements, for example, circumferential grooves in which resilient a sealing O-ring resides, or circumferential wiper seals. The assembly is dimensioned to fit wholly within the chamber, with the circumferential sealing elements establishing a hermetic seal while allowing sliding motion of the free end of the electrostrictive element, and the driver, along the displacement axis.

Abstract: An HGA loader provides HGAs, in succession, to a multiple workstation head tester. An HGAs carrier station receives HGAs to be tested. An alignment station on the base includes an alignment surface which selectively rotates about an alignment axis. A camera generates images of an HGA on the alignment surface, which is rotated so that the HGA has a desired spatial orientation which is maintained as the HGA is transferred to an HGA testing workstation. A received, oriented HGA is positioned to enable read/write test operations on a disk rotating on an adjacent spinstand. To effect the successive position operations, a transporter includes a track overlying the workstations, and a carriage movable along the track, to pass from workstation to workstations. The loader is automatically operative under the control of a controller.

Abstract: A driving circuit is configured to apply a drive signal to a first terminal of a drive piezoelectric actuator having a second terminal coupled to ground. In response, the drive piezoelectric actuator controls the position of a head in a head gimbal assembly. A reference piezoelectric actuator, characterized by dimensional and electro-mechanical properties substantially matching those of the drive piezoelectric actuator, is included in the driving circuit. The driving circuit controls the reference piezoelectric actuator so that a voltage is produced across the terminals of the reference piezoelectric actuator, wherein that voltage is proportional to the charge stored in the reference piezoelectric element. That voltage is transmitted through a buffer amplifier to the drive piezoelectric actuator where it creates in it a charge equal to the charge in the reference piezoelectric actuator.

Abstract: An HGA loader provides HGAs, in succession, to a multiple workstation head tester. An HGAs carrier station receives HGAs to be tested. An alignment station on the base includes an alignment surface which selectively rotates about an alignment axis. A camera generates images of an HGA on the alignment surface, which is rotated so that the HGA has a desired spatial orientation which is maintained as the HGA is transferred to an HGA testing workstation. A received, oriented HGA is positioned to enable read/write test operations on a disk rotating on an adjacent spinstand. To effect the successive position operations, a transporter includes a track overlying the workstations, and a carriage movable along the track, to pass from workstation to workstations. The loader is automatically operative under the control of a controller.

Abstract: An apparatus for securing an HGA to a tester includes a housing with a cylindrical cavity disposed about an axis, and having, at its top end, a mounting surface with a central aperture, for receiving an HGA base plate with a boss hole of the HGA overlying the central aperture. Axially elongated clamp fingers, radially dispersed about a spreader pin, move along the axis between (i) a loading position with upper ends extending through and relatively far beyond the central aperture, and (ii) a clamping position with the upper ends disposed at or near the mounting surface. With an HGA on the mounting surface, and the clamp fingers at their loading position, the clamp fingers are driven downward, while simultaneously, the clamp fingers are driven outward by the spreader pin, and the clamp fingers engage boss hole edges, securing the HGA to the tester.

Abstract: A unitary cartridge, or module, provides a self-contained, high accuracy, ready-to-use assembly for controlling fine positioning of a head gimbal assembly (HGA) disposed on a head mounting unit mounted on the cartridge, with respect to a spinstand or other device associated with a head tester. In a form, the head-mounting unit and a counterweight element are configured to be moveable relative to the base in opposite directions along a displacement axis in response to actuators in the cartridge, and are operative in concert with a damping assembly configured to interact with the counterweight element and the heads mounting unit to mitigate vibrational movement of the cartridge.

Abstract: An apparatus for securing an HGA to a tester includes a housing with a cylindrical cavity disposed about an axis, and having, at its top end, a mounting surface with a central aperture, for receiving an HGA base plate with a boss hole of the HGA overlying the central aperture. Axially elongated clamp fingers, radially dispersed about a spreader pin, move along the axis between (i) a loading position with upper ends extending through and relatively far beyond the central aperture, and (ii) a clamping position with the upper ends disposed at or near the mounting surface. With an HGA on the mounting surface, and the clamp fingers at their loading position, the clamp fingers are driven downward, while simultaneously, the clamp fingers are driven outward by the spreader pin, and the clamp fingers engage boss hole edges, securing the HGA to the tester.

Abstract: An acquisition device includes an analog to digital converter (ADC) composed of multiple interleaved ADCs (sub-ADCs), which receives an analog signal which is converted to digital form. The digitized signal is processed seriatim by a pre-(or trigger-) equalizer, an acquisition memory and a post-(or memory) equalizer. In a calibration mode, frequency responses of the respective sub-ADCs are determined and trigger coefficients are determined for application to the trigger equalizer to effect a preliminary equalization of the digitized signal sufficient to permit operation of the trigger processor in an acquisition mode. Memory coefficients are determined based on residual frequency responses of the sub-ADCs, for application to the memory equalizer. A trigger processor is responsive to the trigger equalizer to select a subset of samples of the digitized signal for loading to the acquisition memory.

Abstract: An acquisition device includes an analog to digital converter (ADC) composed of multiple interleaved ADCs (sub-ADCs), which receives an analog signal which is converted to digital form. The digitized signal is processed seriatim by a pre-(or trigger-) equalizer, an acquisition memory and a post-(or memory) equalizer. In a calibration mode, frequency responses of the respective sub-ADCs are determined and trigger coefficients are determined for application to the trigger equalizer to effect a preliminary equalization of the digitized signal sufficient to permit operation of the trigger processor in an acquisition mode. Memory coefficients are determined based on residual frequency responses of the sub-ADCs, for application to the memory equalizer. A trigger processor is responsive to the trigger equalizer to select a subset of samples of the digitized signal for loading to the acquisition memory.

Abstract: An adjustable disk stabilizer for a spinstand having a spindle motor and spindle assembly for supporting and rotating a magnetic medium bearing disk. The spinstand is adapted to position a transducing (read/write) head adjacent to the magnetic medium. The adjustable disk stabilizer is attached to a stationary portion of the spindle assembly, and includes a mechanism to adjust height and alignment of a plate having a bearing surface opposite a non-magnetic-media-bearing undersurface of the disk. That bearing surface, in concert with the undersurface of the disk, establishes a supporting air bearing therebetween during rotation of the media-bearing disk. The adjustment mechanism enables easily-attained compensation for various disk-to-disk thicknesses and level imperfections of the bearing surface plate mounting, and enables precision alignment of the bearing surface of the plate to the surface of the disk opposite to the surface under test.

Abstract: A removable cartridge for magnetic head and disk testers is disclosed. The removable cartridge includes: a base plate; a first end of an actuator rigidly fixed to the base plate; an HGA mounting block rigidly fixed to a second end of the actuator; a first end of a flexure rigidly coupled to the HGA mounting block; and a second end of the flexure rigidly coupled to the base plate.

Abstract: A system and method are described for aligning a data axis of one or more circular data-bearing tracks on an annular surface region of a magnetic media-bearing disk, with a spin axis of a spindle of a spinstand or a disk drive. The data axis is perpendicular to the surface region of the disk and the data tracks are concentric with respect to a data axis.

Abstract: A system and method are described for aligning a data axis of one or more circular data-bearing tracks on an annular surface region of a magnetic media-bearing disk, with a spin axis of a spindle of a spinstand or a disk drive. The data axis is perpendicular to the surface region of the disk and the data tracks are concentric with respect to a data axis.

Abstract: A headstack locator assembly for locating and fixing a headstack on a spinstand and which mitigates the aforementioned prior art limitations. The headstack locator assembly includes a headstack locator received on a fixed locator. The headstack locator connects to a headstack, while the fixed locator is permanently secured to a spinstand. A vacuum is used to clamp the headstack locator to the fixed locator for testing of the headstack. Upon test completion, the headstack locator is released from the fixed locator by applying positive air pressure to the assembly.

Abstract: A headstack locator assembly for locating and fixing a headstack on a spinstand and which mitigates the aforementioned prior art limitations. The headstack locator assembly includes a headstack locator received on a fixed locator. The headstack locator connects to a headstack, while the fixed locator is permanently secured to a spinstand. A vacuum is used to clamp the headstack locator to the fixed locator for testing of the headstack. Upon test completion, the headstack locator is released from the fixed locator by applying positive air pressure to the assembly. More generally, an apparatus and methods for generally locating and reversibly, pneumatically coupling various elements to each other.

Abstract: A vector signal generator with direct RF signal synthesis is disclosed. The vector signal generator comprises an RF signal synthesizer, a switch, and a memory. The RF signal synthesizer is configured for converting baseband IQ signals into a modulated digital RF signal. The RF signal synthesizer is connected to an I input, a Q input, a clock input, a control input, and an output, where the clock input is a clock input of the vector signal generator, the control input is a control input of the vector signal generator, and the output is an RF signal output of the vector signal generator. The switch is configured for selecting a source of IQ signals and is connected to an external I input, an external Q input, a stored signal I input, a stored signal Q input, the control input, an I output, and a Q output. The external I input and external Q input are external IQ inputs to the vector signal generator and the I output and the Q output are connected to the I input and the Q input of the RF signal synthesizer.

Abstract: A headstack locator assembly for locating and fixing a headstack on a spinstand and which mitigates the aforementioned prior art limitations. The headstack locator assembly includes a headstack locator received on a fixed locator. The headstack locator connects to a headstack, while the fixed locator is permanently secured to a spinstand. A vacuum is used to clamp the headstack locator to the fixed locator for testing of the headstack. Upon test completion, the headstack locator is released from the fixed locator by applying positive air pressure to the assembly. More generally, an apparatus and methods for generally locating and reversibly, pneumatically coupling various elements to each other.

Abstract: Disclosed is a method of measuring frequency distortions characteristics of a device under test, the device configured convert an input signal in an input frequency range to an output signal in a different output frequency range. The method includes, for each test frequency fi, where i=1, . . . , N and N a positive integer, in a selected frequency range, providing a corresponding test signal with multiple frequency components having a measurement component with a frequency fi, a first reference component with a frequency fA, and a second reference component with a frequency fB; inputting the test signals into the device under test; measuring output test signals at the output of the device under test corresponding to the input test signals; and determining, for each test frequency fi, information representative of frequency distortions based on the corresponding input test signal and the corresponding output test signal.

Abstract: Disclosed is a method of measuring frequency distortions characteristics of a device under test, said device configured convert an input signal in an input frequency range to an output signal in a different output frequency range. The method includes, for each test frequency fi, where i=1, . . . ,N and N a positive integer, in a selected frequency range, providing a corresponding test signal with multiple frequency components comprising a measurement component with a frequency fi, a first reference component with a frequency fA, and a second reference component with a frequency fB; inputting said test signals into the device under test; measuring output test signals at the output of the device under test corresponding to the input test signals; and determining, for each test frequency fi, information representative of frequency distortions based on the corresponding input test signal and the corresponding output test signal.