Showing papers by "Hewlett-Packard published in 1969"

A Quartz Resonator Pressure Transducer

Abstract: A digital pressure transducer has been developed utilizing a precision 5 MHz piezoelectric quartz resonator. The circular resonator exhibits linear changes in frequency when subjected to radial compressive stresses. A cylindrical quartz tube, integral with the circular resonator, acts as a diaphragm and transfers and concentrates the stress from the applied pressure onto the periphery of the resonator. Since the tube and resonator are fabricated from a single quartz crystal, nonelastic effects are minimized. The transducer has a dynamic range of 107and a pressure range of 0 to 104psia.

Physical modeling of the step recovery diode for pulse and harmonic generation circuits

Abstract: A simple charge-controlled switching model describes most fundamental aspects of the step recovery diode. However, it is shown that switching speed and the associated loss are related to the width of the i layer and to the doping level. A switching model appropriate for general computer use is given, and examples of its application are shown in pulse and harmonic generator circuits.

Gain saturation and diffusion in CO 2 lasers

Abstract: The effect of rotational-vibrational relaxation and molecular diffusion on the saturation parameter of the CO 2 laser is investigated experimentally. A summary is presented of how the theory of a two-level system can be extended to a multilevel laser system like the CO 2 laser. Published experimental results for the rate of relaxation of the upper levels are such as to suggest that diffusion effects can play an important role in laser beams with radii of less than a few millimeters. For experimental verification of the diffusion hypothesis, the gain of a sealed CO 2 amplifier is measured as a function of input power for four different beam radii. The equivalent saturation parameter derived from these measurements decreases monotonically from 97 to 25 W/cm2as the average input beam radius increases from 0.9 to 2.5 mm in the 9-mm-radius discharge tube of the amplifier.

The crystal resonator- a digital transducer

Abstract: Precision piezoelectric quartz resonators have evolved during a half century of research, development, and engineering. It is an evolution that started with rudimentary concepts and a precision of one part in a thousand, and emerged today with a precision of a few parts in 1012. Although there have been significant steps forward through single contributions, the evolution has been a continuous improvement with an order of magnitude achieved every five to seven years. Not that anyone was particularly aware of these milestones, but, viewed in total, this improvement of a billion to one must stand as one of the truly amazing developments of this electronic age.

Data link test method and apparatus

Abstract: A controllable shift register is used in testing circuitry which measures statistical error rates and synchronization loss rates on digital data links such as are used for transmission of pulsecode modulated (PCM) signals by injecting into the data link a digital test signal having accurately known statistics and then comparing the resultant received signal with a test signal generated at the receiver for providing the desired error information.

High-voltage power amplifier circuit

Abstract: A power amplifier circuit is capable of providing high-frequency output signals over a wide voltage range. At least two transistors are coupled in series to a load terminal and the transistors are energized by respective voltage sources having different magnitudes. The transistors are biased so that they operate as amplifiers in sequence in response to an input signal of increasing magnitude. The overall power dissipation in the circuit is low for a wide range of output signals.

Yig-tuned solid state oscillator

Abstract: An output coupling loop and a tuning loop are supported about a common axis and spaced-apart in parallel planes orthogonally intersecting the common axis. These loops are magnetically coupled by a YIG sphere supported along the common axis with its center positioned between the parallel planes. The output coupling loop is electrically connected by a matched transmission line across a matched load, and the tuning loop (either alone or in combination with a series gap capacitance) is electrically connected by a pair of parallel-connected bypass capacitors across a bulk-oscillating device. One of these bypass capacitors and the bulk-oscillating device are supported on a heat sink in a plane parallel to the common axis and orthogonal to the parallel planes. Both loops, the YIG sphere, and the bulk-oscillating device are mounted in the gap between the poles of a closed loop electromagnet.

Module assembly and method of making same

Abstract: A module assembly includes a sheetlike aluminum substrate, a plurality of semiconductor light emitting elements bonded to one edge of the substrate, and an integrated circuit and metal plane conductor pattern bonded to the lateral surface of the substrate. The conductor pattern and substrate are bonded together by a Teflon FEP coated polyimide film disposed between them. The conductor pattern electrically interconnects the light emitting elements and the integrated circuit and provides input terminals connectable to an external signal source. Selected areas of the module are encapsulated with a very thin layer of silicone compound which is secured to the substrate. The module components are fabricated by bonding and encapsulating steps which permit formation of a thin, mechanically sturdy and integral unit without causing thermal stress in the semiconductor components thereof.

Wave generator having frequency-dependent trigger level for correction of loop delay

Abstract: A wave generator includes an integrator with adjustable upper and lower limit detectors coupled to the output of the integrator for periodically reversing the current applied to the integrator to produce a repetitive triangle wave. The upper and lower levels of the triangle wave at which the detectors are actuated are altered as the operating frequency of the circuit increases.

Emitter controlled negative resistance in GaAs

Abstract: A triode which uses the negative differential mobility of GaAs is proposed for various microwave applications and is analyzed as an oscillator. With proper bias conditions, this device has a microwave equivalent circuit that is simply a capacitance in parallel with a negative resistance. The magnitude of the negative resistance is controlled by injected current. The major characteristics as an oscillator are: 1 < −Q < 10 for nL ⋍ 1011 cm−2 and 107 < fL < 108, maximum device efficiency between 15 and 20 per cent, power density approximately 110 that of LSA mode device, absence of noise associated with domain formation, and third terminal control of negative resistance. The maximum efficiency as an oscillator is available over a finite range of current density, which decreases as nL increases.

Electron spectroscopy system with a multiple electrode electron lens

Abstract: A source of X-radiation and a target under study are mounted on the Rowland circle of a crystal monochromator employed to focus a characteristic line of the X-radiation on the target. An electron lens with four electrodes for providing three independently variable electrical parameters is mounted in the photoelectron path between the target and an electron spectrometer adjusted to focus photoelectrons within a fixed energy range on a detector. The electrical parameters of this electron lens are adjusted to provide a target image of constant size and position at the entrance of the electron spectrometer while accelerating or decelerating photoelectrons from the target into the energy range for which the electron spectrometer is adjusted.

System for simultaneous display of ecg and heart rate

Abstract: A cathode ray tube system receives a cardiac signal and simultaneously produces two displays corresponding to the analog form of the cardiac signal and the heartbeat rate. The displays are generated by separate horizontal and vertical deflection circuits which are alternately switched to drive the cathode ray tube beam. The display of the heart rate is a picture of a bar graph, the length of which changes to indicate the moving average of the heart rate. The bar graph is produced by generating a horizontal line raster and selectively blanking and unblanking the cathode ray tube. High and low limit markers and alarm circuitry associated with the bar graph display operate to indicate when the heart rate moves outside a preset range.

Batch fabrication of integral-heat-sink IMPATT diodes

Abstract: A new technique for IMPATT-diode fabrication is described, in which the critical portion of the diode heat-flow path is formed as an integral part of the diode. The technique has economic advantages over conventional methods in that all processing steps are performed while diodes are still in wafer form. In addition, the technique permits passivation using standard dielectric deposition techniques, and the diode geometrical shape is such as to suppress premature edge breakdown. Typical experimental results are shown.

Hybrid integrated circuit module

Abstract: A visual display module includes a thin thermally conductive substrate. The substrate has a narrow top edge surface on which a linear array of closely spaced electroluminescent display elements are mounted, a bottom edge surface along which there are disposed terminals for receiving input power and binary coded signals for controlling the display elements, and a lateral surface on which an integrated circuit chip and a signal conductors are located. The integrated circuit chip contains a decoding network for selectively addressing the display elements in response to the binary coded signals, write-erase gating means for conditioning an addressed display element into an ''''on'''' or ''''off'''' state, and memory circuits for holding each display element in its ''''selected'''' state. The display elements are disposed in a viewing plane perpendicular to the lateral surface of the substrate, so that a plurality of modules can be stacked adjacent to one another to produce an expandable high density display field.

Dc stabilized wide band amplifier

Abstract: A wideband stabilized wide band amplifier is constructed to have two signal paths, one designed for optimum high-frequency performance and the other designed for optimum low frequency and DC performance. The signals in the two paths are combined in a differential amplifier and the output fed back to the DC signal path in such a manner that any DC signal drift in the AC signal path is reduced.

Molecular Rotational Resonance Spectroscopy

Abstract: A number of recent review articles have summarized the application of Molecular Rotational Resonance (MRR) spectroscopy to the area of molecular structure determinations and described how these applications have applied to chemistry. This article will briefly review this established area of MRR spectroscopy and describe two developments that offer the promise of expanding the applicability of MRR spectroscopy. The first development was the observation that some large molecules (by MRR standards) give a series of relatively intense, equally spaced bands that can be quickly recorded and assigned. The other development has been in the theory, procedures, and instrumentation required for accurate intensity measurements. These two developments, examples of each, and the implication of each for use by chemists, as well as molecular structure determinations, will be discussed. Spectrometers that are being used for studies in this established area and the two newer areas will be described in the Appendix.

Experimental study of flicker noise in m.i.s. field-effect transistors

Abstract: The experimental dependence of flicker noise on the geometry parameters of m.i.s. field-effect transistors is presented. It is found that the gate-referred r.m.s. noise voltage en in the flicker region is inversely proportional to the square root of the gate width of the device. It is also observed that en is directly proportional to the effective gate-insulator thickness. These experimental results are in good agreement with the published results of flicker-noise analyses. Thus, for a given surface State density, it is possible to reduce the magnitude of flicker noise by a control of device geometry parameters.

Ultrasonic transmitter switching circuit

Abstract: Two ultrasonic transducers are pulsed from respective capacitor discharge circuits which are driven from a single high voltage, high speed, silicon-controlled rectifier switch. Low-power current shunting switches are operable to selectively disable the capacitor discharge circuits and their associated transducers.

Counting apparatus and method using separate counters for reference and unknown signal

Abstract: Improved apparatus and method for determining the rate of recurrence of input events involves counting recurring input events and recurring reference events for a period of time that is determined by the desired length of measurement period, and the timing of the input events. The desired output indication of recurrence rate of input events is provided by arithmetically dividing the arbitrary number of input events occurring within the measurement period by the arbitrary number of reference events occurring within the same measurement period.

True rms converter

Abstract: A pair of thermocouples having elements connected respectively to receive an applied signal and the output signal of an amplifier are connected to apply the resultant thermocouple signals to the input of the amplifier in polarity opposition. An additional feedback signal which varies directly with the output level of the amplifier and which has a square-law characteristic similar to the thermocouple elements is applied to the input of the amplifier to reduce the effects of signal level on the response time of the circuit and allow ultralow signal frequencies to be accurately measured.

On-Line Simulation of Block-Diagram Systems

Abstract: This paper is concerned with a general approach to the on-line simulation of block-diagram systems. These systems may be analog, digital, or hybrid; memory or memoryless; explicit or implicit (i.e., possessing loops of memoryless elements); vector or scalar; or of a more specialized nature, such as dynamic systems with integrators as memory elements; and simulation may be conducted in one or more dimensions, such as time and/or space.

The Schottky barrier cold cathode

Abstract: Cathodic vacuum emission from forward biased, rectifying contacts between n -type GaP, ZnSe and ZnS and thin Ag films covered with a monolayer of Cs agrees with a simple theory which assumes isotropic scattering of hot electrons on transmission through the interface between the semiconductor and the Ag. The maximum measured emission efficiency is 6 × 10 −3 per cent but at least 2 per cent is expected with further development.

Keyboard entry means and power control means for calculator

Abstract: Internal control and subroutine logic transfers data between a keyboard input, a random access memory, and a plurality of flipflop registers to perform arithmetic operations and transfers the results of these operations to a cathode-ray tube output display. Power switching is employed in the internal control and subroutine logic so that the subroutines and the instructions of the calculator are supplied with power only when they are to be executed. When a random access memory cycle is required, it is automatically interposed between the otherwise regularly recurring logic cycles by the internal control and subroutine logic. Encoded transfer vectors are stored and decoded by the subroutine logic to permit unrestricted subroutine returns. In the keyboard input two power supply returns are employed to define one bit of the keyboard encoder. The random access memory is partitioned into one portion addressed by a single bit in an address register and into another, larger portion addressed by the remaining bits in the address register. Each flip-flop of the machine is a J-K flip-flop provided with an adjustable threshold for noise immunity and with a high internal gain on the J-K inputs. In the cathode-ray tube output display, a recurring pattern generated by integration in only two directions is selectively blanked to display the results of the operations performed by the calculator. A tester may be connected to the machine for allowing all subroutines to be operated in a single step mode. The tester is provided with switches for initializing any internal state of the machine or stopping normal execution under any prescribed conditions and with apparatus for accessing the random access memory.

Three phase regulated d.c. power supply with control for balancing input phase current

Abstract: A POWER SUPPLY SYSTEM HAS A REGULATED DC OUTPUT AND A THREE PHASE AC INPUT INPUT CURRENT IN EACH PHASE IS CONTROLLED BY A SILICON CONTROLLED RECTIFIER (SCR) THREE BLOCKING OSCILLATORS PRODUCE OUTPUT PULSES FOR FIRING THE SCAR''S AT PHASE ANGLES DETERMINED IN RESPONSE TO THE DC OUTPUT VOLTAGE AND CURRENT ADDITIONALLY THE FIRING ANGLES FOR TWO OF THE THREE SCR''S ARE AUTOMATICALLY ADJUSTED TO BALANCE CURRENT AMONG THE THREE PHASES AT THE INPUT THIS IS ACHIEVED BY CIRCUITRY WHICH SENSES AND COMPARES THE POSITIVE AND NEGATIVE INPUT CURRENT IN TWO OF THE PHASES AND PRODUCES DIFFERENCE SIGNALS WHICH DRIVE TWO FO THE BLOCKING OSCILLATORS TO ADJUST THE FIRING ANGLES OF TWO OF THE SCR''S UNTIL PHASE CURRENT IS EQUALIZED

Television synchronizing system

Abstract: A sync stripper removes the picture signal from the composite video input signal leaving a composite synchronizing signal that includes horizontal and vertical sync pulses An oscillator produces a periodic timing signal having a repetition rate equal to twice that of the horizontal sync pulses This timing signal is supplied to a binary scaler to produce a synchronizing signal for periodically triggering a horizontal deflection circuit at a repetition rate equal to that of the horizontal sync pulses A feedback circuit, responsive to this synchronizing signal and to the composite synchronizing signal, phase locks the oscillator to the composite synchronizing signal and maintains the repetition rate of the oscillator at twice that of the horizontal sync pulses The timing signal is also supplied to a gate that is periodically enabled in response to the vertical sync pulses to provide a synchronizing signal for periodically triggering a vertical deflection circuit at a repetition rate equal to that of the vertical sync pulses