Abstract: A method of calibrating an analog machining sensor of the varying resistance type which has been deposited on a surface involves depositing adjacent it with great positional accuracy relative to a feature on the surface, discrete machining sensors. As machining takes place, the discrete sensor's continuities are successively broken as the analog sensor's height is reduced and its resistance increased. Measuring the resistance of the analog sensor at the time each discrete sensor breaks yields values from which the position of the analog sensor's machined edge can be very accurately related to the position of the feature on the surface.

Abstract: Apparatus for measuring the peak amplitude of an input signal includes a comparator for comparing the input signal against a reference signal. The comparator selectively drives a latch which in turn drives a successive approximation register. The count in the successive approximation register is selectively increased or decreased by a predetermined amount, depending on the condition of the latch and the count in the register. The register count is converted by a digital-to-analog converter to provide the reference signal.

Abstract: An elongated carriage has a first capacitive probe disposed from its top surface opposite to an object surface, and a second capacitive probe disposed from its bottom surface opposite to a level reference surface. An arm is orthogonally disposed from the elongated carriage member to provide lateral support. The carriage is moveably supported at opposite ends of the elongated member and at the distal end of the arm by three rolling members which roll in corresponding grooves of supporting members as the carriage is moved in lateral increments with respect to the stationary object and reference surfaces. The first capacitive probe and the object surface comprise a first capacitor, and the second capacitive probe and the reference surface comprise a second capacitor. As the carriage moves laterally, the first probe is moved across the object surface while the second probe is moved across the reference surface. The capacitance of each probe is translated into a distance measurement.

Abstract: A disk is rotated at high speed on a spindle while fluid carrying magnetic medium material is applied to the disk through a dispensing nozzle which starts at the outside diameter of the disk and travels to the inside diameter, pauses momentarily, and then travels back to the outside diameter. As the fluid is applied, a thin film of medium material adheres to the disk while the excess fluid forms a protective coating over this thin film as it flows radially off of the disk due to the centrifugal force generated by the high speed of rotation. The nozzle discharge pressure and the high rotational speed of the disk result in a very thin film of magnetic medium material being applied to the disk. The rate of nozzle travel can be adjusted to vary the medium material film thickness. Immediately following the high speed coating application step the speed of the disk is substantially reduced and the disk is exposed to a magnetic orienting field during an orientation step.

Abstract: In a first searching mode of the control program for the microprocessor, the microprocessor starts with a selected clock input and associated delay circuit and sets the delay circuit to an initial clocking point which is intermediate to the minimum and maximum delay points. The microprocessor then, at each pass of the control program, successively increments the delay period interposed by the delay circuit to cause the clock pulse to arrive later and later in time at the clock input until the associated circuit fails, to indicate the late clocking failure limit. In the second searching mode of the microprocessor control program, the microprocessor starts at the late clocking failure limit and at each subsequent pass of the program successively decrements the delay period interposed by the delay circuit to cause the clock signal to arrive earlier and earlier in time until the semiconductor device fails again, to indicate the early clocking failure limit.

Abstract: A flat coil velocity transducer includes a thin, flat coil mounted to a member whose velocity is to be measured. The convolutions of the coil are skewed so that regions at opposite ends of the coil contain predominantly upper or lower legs of the convolutions. The coil moves transverse to a magnetic field to induce voltage in the legs of the coil. However, the field induces voltage in one, but not the other, end region so that a resultant voltage is induced in the coil dependent on the strength and direction of the magnetic field, the number and length of the legs in the region, and the direction and velocity of movement.

Abstract: A wedge/taper alignment ring is used to hold the objective lens of a laser light pen in place. The ring is free to move in the axial direction under forces of thermal expansion and shock, decreasing distortion and misalignment to the objective. Moreover, it centers the mechanical axis of the objective to that of the housing. A spring with a high restoring force moves the ring back into place.

Abstract: In an electron beam lithography apparatus a capacitance height gauge is used to determine the distance between a reticule and electron optics. In order to calibrate the capacitance gauge an optical interferometer, including a mirror are mounted on the same axis as the capacitance gauge. The mirror is moved a predetermined distance so that the movement distance measured by the capacitance gauge and the interferometer can be compared.

Abstract: Apparatus for precisely machining the surface of a workpiece comprises a rotating plate with a flat, horizontal abrasive-laden surface against which the workpiece surface is forced by gravity. The workpiece is carried on the free end of an arm pivotably supported remote from the end of the arm carrying the workpiece. Loading of the workpiece work surface can be varied by shifting weights along the length of the arm or transverse to the length of the arm. The workpiece itself can comprise a bar on which several magnetic transducing heads have been deposited. Machining the workpiece surface to a preferred position accurately defines a dimension of choice, such as the throat height of these transducers.

Abstract: A method of calibrating a capacitance height gage for an electron beam lithography machine. The electron beam apparatus having the capacitance height gage to be calibrated is first mounted in a calibration fixture wherein the distance between the gage and a calibration reticle is adjusted using a laser interferometer. The electron beam is directed to a center high backscatter point, and then deflected to a predetermined high backscatter point. The capacitance gage readings and deflection voltages are measured to define a calibration plane. The electron beam apparatus is then repositioned to the lithography station having a reticle positioned below the electron beam. The distance to the reticle is measured with the capacitance gage, and the deflection of the electron beam during lithography operations is adjusted according to the variation of the reticle plane from the calibration plane.

Abstract: In the process for manufacturing the ferrite cores used in magnetic data transducer heads, a novel stacking of the bars from which the core pieces are cut allows these bars to mutually shield each other's back gap areas during the alumina sputtering step which sets the lengths of the read/write flux gaps. An inexpensive fixture supports the bars in the desired position during the sputtering operation.

Abstract: A data recovery circuit useful in magnetic data recording systems employs doublet pulses to at least partially encode data. Measurement of the slope of the transition between doublet pulse half-cycle peaks and of the amplitude of this transition allows rejection of high frequency low amplitude noise and high amplitude low frequency noise. The use of nearly the entire peak-to-peak voltage swing of doublet pulses makes identifying them relatively reliable.

Abstract: An improvement in a wind electric generation system of the type disclosed in Jacobs et al. U.S. Pat. Nos. 4,059,771, 4,228,361, and 4,228,362, with particular reference to U.S. Pat. No. 4,228,361.

Abstract: A magnetic read head has a first embodiment comprising an elongated magnetoresistive element having a central region and distant ends. The central region has equipotential strips disposed intermediate to its ends, and detection circuitry is electrically connected to these intermediate equipotential strips to sense the changing resistance of the central region in the presence of data magnetically recorded on a medium. In a second embodiment, the magnetoresistive element is folded into a picture frame shape and has its ends joined. The element is vertically arranged so that one of the legs of the element is positioned in proximity to a selected track of a recording medium. A pair of equipotential strips are disposed at opposite ends of the leg to define a sensing region therebetween. Detection circuitry is connected to these equipotential strips to detect the changing resistance of the sensing region in the presence of the magnetic fields of the medium.

Abstract: In a bubble memory package, a contoured, shaped magnet and filler plate combination is provided to shape the magnetic field in a uniform fashion to prevent the loss of magnetic flux density which normally tends to occur in the center of the magnet area of a planar, uniformly thick magnet.

Abstract: A computer cooling system has a mixing valve which supplies coolant to the computer and receives hot return coolant from the computer and also chilled return coolant from a chiller intermediate the computer and the mixing valve. The mixing valve mixes the hot return coolant with the chilled return coolant to adjust the cooling system temperature. Control circuitry senses, or estimates, the dew point temperature of the computer room environment, compares it with the cooling system temperature, and adjusts the mixing valve to maintain the cooling system temperature a few degrees above the dew point temperature. A condensation sensor comprised of a light emitting diode (LED), reflective tape applied about a cooling system supply conduit, and a phototransistor is disclosed. Light from the LED is fully reflected by the reflective tape to the phototransistor in dry conditions, but only partially reflected when condensation forms on the tape.

Abstract: A hardware network or system is disclosed for testing LSI and VLSI logic device design and system design by simulation utilizing individual gate functions. The simulator system uses switching logic, random access memory, and a state table device to simulate particular test routines to test device design with functions which may appear in random or semi-random sequence.

Abstract: Connector assemblies are provided for mounting leadless chip carriers to a printed wiring board (PWB). Each connector assembly includes an elongate rigid and electrically insulative body, and electrically conductive leads. The body has two rows of pockets, each containing a lead. Each lead has two widened contact sectors. The shape of the lead is such that with one end mounted in the PWB, the sectors are opposite one another and approximately the same distance from the PWB. Each connector assembly is mounted by soldering the body to the PWB and mounting one end of each lead to the PWB. Each pocket has a channel narrower than the sector and wider than the general lead width, to restrain its associated lead to flexing movement in one direction transverse to the body. The sectors are offset in this transverse direction from the lead end mounted to the PWB, but in different amounts, thus to enable a staggered positioning of adjacent leads.

Abstract: An equipment module for holding printed circuit boards. The equipment module contains pin and slot combinations which permit it to be lifted from a casing and tilted for efficient access to the printed circuit boards for maintenance. The pin and slot combinations comprise a plurality of slots molded into the sides of the equipment module for cooperation with pins mounted on the casing.

Abstract: This amplifier circuit for a magnetic transducer such as a magnetic head includes a pair of transistors which function both as write current modulators and read signal preamplifiers. The transistors are suitable for in situ deposition on a magnetic transducer carrier adjacent the winding, which keeps the signal lines of the data read by the transducer very short until amplification.