Showing papers by "Hewlett-Packard published in 1970"

A new look at yield of integrated circuits

Abstract: Expressions are derived for integrated-circuit yield as a function of active circuit area, using as a model random distributions of indistinguishable spot defects. Previous attempts to calculate integrated-circuit yield have used a nonrandom distribution of distinguishable spot defects as their model.

Band Structure and High-Field Transport Properties of InP

Abstract: Using the technique of energy-distribution analysis of photoemitted electrons, we have accurately located the position of several band-structure features of InP, including the next higher conduction-band minimum above the ${\ensuremath{\Gamma}}_{1}$ minimum at 1.95 eV above the valence-band maximum, independent of temperature. This minimum is tentatively associated with the ${L}_{1}$ symmetry point. High-temperature Hall-effect measurements confirm that there are no minima between the lowest two observed by photoemission. A band structure for InP has been computed using these new data in an empirically adjusted first-principles orthogonalized-plane-wave (OPW) calculation. The velocity-field characteristic has been calculated for a range of lattice temperatures. A negative differential mobility is predicted, with a room-temperature threshold field of 11 500 V/cm and a peak drift velocity of 3\ifmmode\times\else\texttimes\fi{}${10}^{7}$ cm/sec.

Light-emitting diode package with dual-colored plastic encapsulation

Abstract: A light-emitting diode (LED) is bonded to a pair of metal leads which are attached to a metal lead frame with a plurality of lead pairs, such that its optical axis is parallel to the longitudinal axis of the leads. The device so formed is encapsulated in two colors of plastic, a clear portion over the diode to transmit light from the diode and a dark portion behind the diode to improve the diode on-off contrast and make a hermetic seal with the leads. After encapsulation individual devices are separated from each other by cutting the leads from the lead frame.

An orbiting clock experiment to determine the gravitational red shift

Abstract: Orbiting clock experiment for measuring gravitational red shift of earth by comparing ground based and satellite-borne hydrogen maser clocks

Integrated circuit read only memory bit organized in coincident select structure

Abstract: An integrated circuit read only memory fabricated on a single semiconductor chip, the memory cell array being arranged with orthogonal sets of access lines providing coincident selection of unidirectional current devices, for example, base-emitter diodes, at the junctions of the access lines. The memory cells are read by detecting the presence or absence of current flow through one or more selected cells. One set of access lines is formed by base diffusion stripes spaced apart in a common-collector isolation well. The orthogonal set of access lines is formed by metal lines overlying the base stripes and the individual emitters diffused in the base stripes at the points of intersection with the metal lines. Programming of the bit pattern is accomplished by contacts between the emitters and the metal lines at selected cross-over points. An improved inverter circuit is provided in the memory array access circuitry.

Transistor noise measuring apparatus

Abstract: An improved instrument measures noise power generated by a transistor under selected test conditions. Automatic adjustment of gain from the input of the transistor under test through succeeding stages provides an accurate readout of noise generated within the transistor under test.

Rf sputtering system with the anode enclosing the target

Abstract: The plasma in an RF sputtering system is confined to the region between the anode and target by enclosing the target with the anode. The anode is in two parts which are connected electrically through sliding contacts that allow removal of one of the parts for access to the interior region of the anode.

Fluid flow meter

Abstract: A fluid is passed through first and second thermally conductive porous conduit elements spaced apart from one another along the path of fluid flow. A heater and a temperature sensor are mounted on each porous element and operated to maintain the two elements at constant preset differential temperatures. Flow rate of the fluid is indicated by the electrical power supplied to the heater on the second porous element to maintain the preset temperature differential. Temperature controlled metal cylinders surround the porous elements to insulate them from the adverse effects of the ambient temperature. A shaped conduit between the porous elements further minimizes heat loss from the fluid and improves measurement accuracy.

Method and apparatus for averaging the digital display for a fluctuating digital measurement and improving the resolution of the measurement

Abstract: A digital display system in which fluctuations in the last one or two numbers of a repetitive display value are removed by an averaging technique comprising the steps of determining the difference between the new incoming digital value and the last digital display value, taking a certain preselected percentage such as one percent of the difference between the new value and the last display value, and adding the new computed digital value to the value of the last display to produce a new average value for display. The resolution of the incoming digital values is increased by a statistical interpolation process whereby, in averaging over a large number of quantized incoming values, the resolution of the displayed values exceeds that of the quantization-limited input. This technique, as well as an alternate averaging system, is employed to reduce the jitter and enhance the resolution of the digital display of a distance measuring interferometer.

Design considerations for a high-speed bipolar READ-ONLY memory

Abstract: A monolithic, fully-decoded 1024-bit read-only memory, with less than 50-ns access time and 350-mW power dissipation, will be discussed. The ROM can be bit-organized with a coincident select structure to minimize pin count and address decoders.

Hypothesis for the Schwarz-Hora Effect

Abstract: This note shows that the effect observed in the Schwarz-Hora experiment, in which an electron beam passing through a crystal irradiated with laser light proceeds to a nonfluorescent screen and radiates light the same color as the laser, is probably caused by electron bunching. The crystal provides a sharply defined region of electric field amplitude which makes bunching possible.

Regulating converter circuit

Abstract: An improved high-efficiency D.C.-to-D.C. converter circuit uses a single transistor to provide both D.C. level conversion and output regulation. A control winding on a saturable core inductor alters the recycle time of the converter to control the level of magnetic flux in an output transformer per cycle of operation.

Method and apparatus for the measurement and display of error values of precision machine tools, electronic instruments, etc.

Abstract: A system for measuring and plotting a sequence of error values, for example the positioning errors of machine tools as a function of distance along an axis of travel, the output frequency errors in voltage controlled oscillators, and the like is described. The system for positioning error plotting comprises a laser interferometer for measuring the actual distance of movement of the machine and a novel and simple calculator system including a pair of digital-to-analog converters coupled to the interferometer for determining from this laser interferometer measurement both the desired (or assumptive) distance of movement of the machine and the error distance between the actual distance and the desired distance. By assuming the desired position of the machine, complex interconnections to its controller are avoided. The calculated error distance and distance at which the error occurred are plotted on an X-Y recorder. A similar technique is described for the calibration of voltage controlled oscillators.

Acousto-optic band reject light filter and apparatus using same

Abstract: An acousto-optic band reject light filter is disclosed. The light filter includes an optically anisotropic medium, such as a birefringent crystal, in which an acoustic wave is excited at a certain selected radiofrequency corresponding to a selected optical frequency to be rejected. The crystal is disposed to receive an incident light beam containing the selected optical frequency to be rejected. The light beam is collinearly diffracted on the acoustic wave within the optically anisotropic medium to diffract light of a first polarization and of the selected optical frequency related to the acoustic frequency into light of a second polarization. The diffracted light beam is then passed through a polarization analyzer to reject from the diffracted light beam light of the second polarization while retaining in the diffracted light beam light of the first polarization. The selectable frequency in the light beam which is to be rejected can be tuned over a wide band by tuning the frequency of the acoustic wave within the crystal.

Method and apparatus for control of light transmission through an anisotropic medium

Abstract: An electronically tunable acousto-optic filter is disclosed of the type wherein light of a first polarization is diffracted on an acoustical wave traveling collinearly of the light in an anisotropic birefringent medium to shift the polarization of the light from a first polarization to a second polarization. The intensity of the acoustic wave in the birefringent medium is varied to vary the ratio of the intensity of the light diffracted from the first polarization into the second polarization. The band pass of the acousto-optic filter is electronically tuned by varying the frequency of the acoustic wave in the birefringent medium. The acousto-optic device may be employed as an attenuator, chopper, or modulator for light.

Subroutine call and return means for an electronic calculator

Abstract: Two electronic calculator keys provide unconditional GO TO and subroutine call/return and return functions. A GO TO instruction followed by an alpha-numerical address causes the calculator to unconditionally branch to the address indicated. The GO TO instruction followed by a SUB instruction and an alpha-numerical address causes the calculator to unconditionally branch to a subroutine at the address indicated, and the SUB instruction alone causes the calculator to unconditionally branch (return) to the address it was at when it branched to the subroutine.

Frequency-measuring system utilizing means for momentarily stopping the variable frequency generator

Abstract: A variable frequency receiver scans a spectrum of frequencies from a signal source, and a cathode-ray tube (CRT) system detects and displays the amplitude of the signal source as a function of the frequencies scanned. At any selected point of the amplitude response curve, the frequency scanning is momentarily stopped to produce a marker spot on the CRT screen. During the stop time, a digital counter counts the frequency of the variable frequency generator. Timing and logic circuitry controls the intensity of the marker spot and the length of the stop time in response to the counting time and the frequency scanning rate.

Resonant piezoelectric acousto-optic light filter and apparatus using same

Abstract: An acousto-optic light filter is disclosed wherein a radio frequency electric field is employed to excite an acoustic wave in a piezoelectric optically anisotropic medium. The light to be filtered is collinearly diffracted on the acoustic wave to shift light of a first polarization and of a frequency related to the frequency of the acoustic wave, into light of a second polarization. The diffracted light is polarization analyzed to separate light of the second polarization from light of the first polarization. Piezoelectric birefringent crystals are employed for the optically anisotropic medium. Arrays of acoustic resonators are formed by energy trapping in crystalline slabs, such resonators being selectively addressed by applying electric fields to the crystalline slab at the resonant frequency of the selected acoustic resonator. Different overtone resonances of the acoustic resonators are excited to permit the filter to pass light of different frequencies either in time displaced intervals or simultaneously.

Acousto-optic light spectrum analysis

Abstract: An acousto-optic light spectrum analysis method and apparatus is disclosed. A linearly polarized unknown light beam to be spectrum analyzed is collinearly diffracted on an acoustic wave in an optically anisotropic medium to diffract light of the first linear polarization and of a frequency related to the frequency of the acoustic wave into light of a second polarization. The diffracted unknown light beam is polarization analyzed to separate the light of the second polarization from the light of the first polarization. The frequency of the acoustic wave is swept and the light of the second polarization is detected as a function of the sweep to obtain a spectrum analysis of the unknown light beam. The output spectrum of the unknown light beam is calibrated by switching a known light source through the acousto-optic system for calibration of the output spectrum.

Flow-through hollow cathode spectral light source and method of operating same

Abstract: An atomic spectral lamp includes a demountable, hollow cathode, and a funnel-shaped anode adjacent to the cathode. A glow discharge plasma is established in the cathode cavity. Counterflow through the funnel-shaped anode prevents self absorption of light by atomic vapor. Gas flow through the hollow cathode at a predetermined velocity increases the intensity of light-emitted from the plasma.

Down-converters using Schottky-barrier diodes

Abstract: The analysis of noise in down-converters, in which signal and image ports are equally terminated, is extended to include the effect of a nonlinear junction capacitance. The theory is applied to Schottky-barrier diodes, which are represented by a constant resistance in series with a parallel combination of a nonlinear conductance and nonlinear capacitance pumped in phase. Using numerical optimization procedures, the minimum overall receiver noise figure, the associated conversion loss, and the required optimum external terminations are calculated and compared with experimental results. It is shown that in a resistive mixer with equal termination of signal and image ports, the addition of a nonlinear capacitance can lower the conversion loss substantially; but the overall noise figure remains nearly invariant. A conversion loss as low as 3.5 dB was measured (3.3 dB calculated) for a silicon Schottky-barrier diode operated at 3 GHz, driven by 0.1 mW LO power, and without dc bias. The overall noise figure, including an IF amplifier noise figure of 1.5 dB, however, stays at 5.7 dB (5.5 dB calculated).

Switching regulator power supply including fast turnoff means for switching transistor

Abstract: A pulse transformer is added to a switching regulator power supply by placing its primary in series with the commutating diode and its secondary between the emitter and the base of the switching transistor through a bias resistor. When the switching transistor starts to turn off, a pulse from the transformer helps turn off the switching transistor faster by removing the stored charge from the base, thus reducing power dissipation in the transistor.

Acousto-optic rf spectrum analysis method and apparatus

Abstract: An acousto-optic RF spectrum analysis method and apparatus is disclosed wherein radio frequency energy to be spectrum analyzed is employed to excite an acoustic wave in an optically anisotropic medium. A linearly polarized white light beam is collinearly diffracted on the acoustic wave in the anisotropic medium to diffract light of the first polarization and of a frequency related to the frequency of the acoustic wave into light of the second polarization. The diffracted output light is then analyzed to separate light of the first polarization from light of the second polarization. The separated light is spectrum analyzed to obtain a spectrum corresponding to the spectrum of the radio frequency energy to be analyzed.

Angular impact fluid energy mill

Abstract: A fluid energy mill having an inlet chamber, a classification chamber, and an upstack and downstack connecting opposite ends of the inlet chamber to the classification chamber. The inlet chamber, which is positioned angularly to the upstack and downstack, has a Venturi portion between the upstack and downstack. A feed inlet is also positioned angularly to the upstack as well as to the inlet chamber. This feed inlet also has a Venturi portion. A feed hopper is provided above the feed inlet and is in connection therewith. A pressure fluid nozzle is provided below the hopper to project the fluid and particles from the hopper through the Venturi in the feed inlet. A similar but opposed nozzle is provided below the downstack to project fluid through the Venturi in the inlet chamber toward the upstack. The fluid and particles propelled by each nozzle meet and impact below the upstack and the resultant fluid and particles pass upwardly through the upstack and centrifugally move through the mill where the lighter particles are centrifugally separated from the heavier particles and exhausted from the mill.

Acousto optic method and apparatus for mode decoupling a ring laser

Abstract: An acousto-optic method and apparatus is disclosed for mode decoupling a ring laser. A pair of acousto-optic filters is disposed in the optical path of the ring laser for collinearly diffracting the counter rotating light beams on acoustic waves in the acousto-optic filters to shift apart the optical frequencies of the counter rotating light beams in the laser gain medium by a certain frequency related to the frequency of the acoustic waves to prevent mode locking of the optical frequencies of the counter rotating light beams. A rotation rate sensor employing the mode decoupled ring laser is disclosed.