Abstract: A method of characterizing A.C. performance of an integrated circuit based upon D.C. measurements utilizing a process monitor circuit. The process monitor circuit provides a D.C. output having a magnitude which varies with the frequency of an oscillator section of the monitor circuit. The frequency is a function of both A.C. and D.C. performance, therefore the process monitor output signal is indicative of such performance. Since D.C. measurements may be made while the integrated circuits are in wafer form utilizing a conventional wafer prober and parametric tester, it is possible to detect A.C. performance problems very early in the manufacturing process.
Type:
Grant
Filed:
March 19, 1990
Date of Patent:
August 13, 1991
Assignee:
National Semiconductor Corporation
Inventors:
Richard B. Merrill, Edson D. Gomersall, Enayet U. Issaq
Abstract: Mode-locked pulsed output is induced in a laser by introducing a varying frequency dependent loss in the cavity. The varying, frequency dependent loss allows a large number of longitudinal modes to oscillate. In one of the preferred embodiments of the subject invention, the varying frequency dependent loss is generated by reciprocating one of the mirrors of the resonator. In this embodiment, the laser has a resonator with a primary light path defined by first and second end mirrors. A gain medium is located between the end mirrors. A beam splitter is provided for redirecting the light into a secondary light path. A third mirror functions to feed back the light into the primary light path. Pulse formation is induced by varying the path length of one of the two paths by reciprocating an end mirror. Moving the mirror creates varying interference effects when the light energy is recombined at the beam splitter. The mirror is reciprocated relatively slowly, yet ultra-short pulses are generated.
Type:
Grant
Filed:
April 24, 1990
Date of Patent:
August 13, 1991
Assignee:
Coherent, Inc.
Inventors:
Luis A. Spinelli, Gilles A. Feugnet, Bernard J. Couillaud
Abstract: A method and apparatus for joining building panels, such as portable partitions, walls, floors, ceilings, or roofs. A cam device is located in one panel or member and is magnetically operated to engage a mating element located in an adjacent panel or member.
Abstract: An output buffer circuit which converts CMOS logic levels to ECL logic levels. ECL high and ECL low level voltage signals are generated by a reference network. A switch responds to the status of a pair of complementary CMOS inputs to selectively connect one of the ECL voltage signals to an ECL load.
Abstract: An oven using one or more quartz tungsten light bulbs or quartz arc bulbs capable of producing 1.5 kW of radiant energy of which a significant portion is light energy in the 0.4 to 0.7 .mu.m wavelength range impinges high intensity visible light wave radiation directly onto a food item. Light sources can be positioned above and below the food item and the inner walls of the oven are preferably highly reflective to reflect light energy onto the food. The intensity of the visible light source is automatically controllable and can be varied throughout the cooking cycle.
Type:
Grant
Filed:
May 12, 1989
Date of Patent:
July 30, 1991
Assignee:
Quadlux, Inc.
Inventors:
Eugene R. Westerberg, Robert I. Beaver, II
Abstract: An adaptive equalizer for compensating input signal frequency and phase distortion introduced in the input signal transmission media is provided. The adaptive equalizer includes frequency selection means for generating an output signal of a selected frequency in response to the input signal and a feedback signal. A comparator slices the equalizer output at predetermined levels. A controller receives the comparator output and provides a controller output representative of the voltage level of the comparator output. A digital filter receives the controller output and generates a corresponding binary signal as the feedback signal to the frequency selection means.
Abstract: A gable ventilator comprising a vent member which holds and displaces an eaves panel and a bracket which positions and supports the vent member is disclosed. The vent member is provided with a plurality of apertures through which air may pass, is configured to extend the length of the gable wall.
Abstract: An apparatus (12) generates information about the width of pulses in an optical train using an autocorrelation technique. In the apparatus, the incoming beam (10) is split into two paths (10a, 10b). The path length of one of the beams (10b) is varied using a reciprocating stage (40) having a reflector (50) mounted thereon. The stage is driven by a cam (42) rotating at a constant speed. A portion (42b) of the curvature of the cam is arranged such that the distance between the rotational axis (44) of the cam and the stage varies proportionally with the rotational angle of the cam such that the path length of the beam will change at a constant rate. The two beams are then recombined in a second harmonic generation crystal (28) which generates an output signal. The output signal is monitored by a photodetector (30) and may be displayed on an oscilloscope to provide a measurement of the pulse width of the input pulses.
Abstract: The present invention is for an algorithmic method for compressing data. The data is compressed one cycle at a time and stores a data block each cycle. The method includes the steps of forming a storage array of binary bits. The array has a first plurality of columns, a second plurality of rows, a third plurality of right diagonals and a fourth plurality of left diagonals. In the preferred embodiment the array has 30 rows, 30 columns, 59 left diagonals and 59 right diagonals. The array also has a data entry site. The array is also segmented into a plurality of morsels each comprising a collection of a binary bits. A new data block is entered into the data entry site. A fifth plurality of sums is formed representing the sum of binary 1's in each column, each row, each right diagonal and each left diagonal. Each sum is right diagonal and each left diagonal. Each sum is stored into a morsel thereby forming a summation array.
Type:
Grant
Filed:
July 3, 1989
Date of Patent:
July 23, 1991
Inventors:
Gene Willey, John Wakefield, Chris Radcliffe
Abstract: Intrapericardial access is provided by clamping the wall of the pericardium between elongate jaw elements carrying axially aligned tubular guides and passing a guide wire through the guides and the pericardial tissue therebetween. In the preferred embodiment the jaw elements include interengageable ratchets for holding the elements in clamping engagement with the wall of the pericardium and aligned pointed extensions for piercing the pericardial tissue clamped between the elements. Further intrapericardial access is provided by an additional tubular guide carried by the jaw element intended to be disposed in the pericardium during placement of the guide wire.
Type:
Grant
Filed:
September 8, 1989
Date of Patent:
July 23, 1991
Assignees:
Thomas J. Fogarty, Ventritex, Inc.
Inventors:
Albert K. Chin, Thomas J. Fogarty, Eric S. Fain
Abstract: The invention concerns an electrical reversing switch, which is especially suited for switching of high-frequency electrodes. This switch has an over mounted pneumatic cylinder, which moves on pistons arranged on both sides, and thus produces electric contacts.
Abstract: A servo alignment method and apparatus for maintaining laser beam alignment. An operating parameter of the laser (such as output beam power) is measured, and error signals are generated from the measured operating parameter signal for controlling the laser beam alignment. In one class of embodiments, modulation signals are supplied to an intra-cavity component of a laser system to modulate the beam path. The beam path may be modulated by reciprocating a laser resonator mirror about a mirror axis or two substantially orthogonal mirror axes. In the latter case, the mirror may be vibrated about the axes either alternately (first about one axis and then about the other) or simultaneously.
Type:
Grant
Filed:
June 11, 1990
Date of Patent:
July 16, 1991
Assignee:
Coherent, Inc.
Inventors:
James L. Hobart, Wayne S. Mefferd, Bruce Peuse
Abstract: An exercise machine has a front stanchion assembly and a rear stanchion assembly. An inclined monorail is mounted between the stanchion assemblies, and a roller carriage assembly having spool-shaped rollers, is mounted so as to receive the monorail, and roll upon it. The roller carriage is adapted so that a bicycle seat assembly (for use in cross country ski simulation) and a swim bench assembly may be interchangeably rigidly secured to the roller carriage assembly. The monorail may be attached to the front and rear stanchion using a telescoping sleeve to permit adjustment of the monorail orientation.
Abstract: An electrophotographic copying apparatus having an electromechanical optical scanner, optical reflecting and focusing assembly, photosensitive latent electrostatic imaging assembly, electrostatic charge generator and applicator, and electrostatic toner applicator, wherein the scanner and photosensitive assembly have selectably variable operational speeds and the electrostatic charge and toner applicators have substantially constant application rates, and further wherein the speeds of the scanner and photosensitive assembly may be selectably varied to maximize copying rate while minimizing electrostatic charge generation and electrostatic toner consumption.
Type:
Grant
Filed:
November 16, 1989
Date of Patent:
July 9, 1991
Assignee:
Toshiba America Information Systems, Inc.
Abstract: A single transistor electrically programmable and erasable memory cell is disclosed. The single transistor has a source, a drain with a channel region therebetween, defined on a substrate. A first insulating layer is over the source, channel and drain regions. A floating gate is positioned on top of the first insulating layer over a portion of the channel region and over a portion of the drain region. A second insulating layer has a top wall which is over the floating gate, and a side wall which is adjacent thereto. A control gate has a first portion which is over the first insulating layer and immediately adjacent to the side wall of the second insulating layer. The control gate has a second portion which is over the top wall of the second insulating layer and is over the floating gate. Erasure of the cell is accomplished by the mechanism of Fowler-Nordheim tunneling from the floating gate through the second insulating layer to the control gate.
Abstract: A self calibrating algorithmic analog-to-digital converter is disclosed for which the gain of the conversion loop is precisely adjusted and controlled by an array of switched capacitors such control being stored in a latch. The offset of the gain stage is reduced by reducing the amount of charge injected from the gate of the input zeroing MOS switch.
Abstract: A high power injection-locked laser system (10) is disclosed which includes master and slave lasers (12, 14) both of which are solid state lasers having continuous wave outputs. The slave laser has an output power at least ten times greater than the master laser. In the preferred embodiment, the slave laser is at least one-hundred times as powerful as the master laser. In accordance with the subject invention, a servo-loop control system is used to maintain the injection locked condition. A discriminant signal is generated that is indicative of drift in the slave laser cavity. The discriminant signal is used adjust the length of the slave laser cavity to maintain the locked condition.
Abstract: A differential phase shift keying (DPSK) modulator utilizes time-domain filtering techniques. The DPSK modulator includes a data scrambler which receives a serial digital data input signal and generates an output signal representing the dibit value of the serial input sequence. The dibit signal is differentially encoded and then provided to a history generator which produces phase modulating vectors utilizing pulse density modulation (PDM). The carrier waveform is then modulated utilizing the modulating vectors to generate a DPSK output signal.