Abstract: A direct detection receiver for a passive microwave and millimeter wave radiometric imaging system. The receiver includes a balanced switch low-noise amplifier (BSLNA). A front-end, low-noise amplifier (LNA) is inserted before the BSLNA to achieve a low-noise figure, as well as provide sufficient gain to minimize the input noise figure degradation due to loss of the BSLNA. A high-electron mobility transistor (HEMT) diode is used as a power detector. The front-end amplifier, BSLNA and diode are process compatible for monolithic integration.

Abstract: A solid state laser apparatus 10 including a laser gain module 12 for generating high energy laser beams 50 and 52 accompanied by non-lasing radiation 60 which, generates heat in the environment of the laser gain module and the apparatus, generally having an adverse affect on the performance of the apparatus. A heat shield 14 encloses the laser gain module to absorb the non-lasing radiation 60 to shield the components surrounding the shield against temperature increases above levels that adversely affect the laser performance and shields the reflective units 20 and 22. Affixed to the heat shield 14 is a cooling pipe 66 which provides coolant to the roof 64 of the heat shield 14 removing the heat that is absorbed. The pipe 66 is connected to a heat exchanger and pump 24 that circulates coolant through the piping. The heat shield 14 and the cooling apparatus 66 and 24 are designed to keep the temperature increases within 20.degree. C. of the nominal base operating temperature for a particular system.

Abstract: Apparatus for monitoring the mass quantity and density of a fluid in a closed container of fixed volume. A density sensor within the closed container has a density such that the density sensor moves to a first location within the container when the fluid has at least a predetermined density, which corresponds with a predetermined mass quantity of the fluid within the closed container, but moves to a second location within the closed container when the fluid has a density less than the predetermined density. A detector monitors the position of the density sensor. The apparatus can be incorporated into a vehicular air bag system to monitor the density, and thus the mass quantity, of the gas which is to deploy the air bag in the event of an impact.

Abstract: A fingerprint detector that uses a skin resistance sensing array for producing a sample trajectory signal when a fingertip is moved across the sensing array surface. The sample trajectory signal represents the electrical conductance changes in the resistance of ridges and valleys of the fingertip. The fingerprint detector also includes a sampling circuit coupled to a processor. In addition, a technique is disclosed for detecting and verifying a fingerprint by moving a fingertip relative to the skin resistance sensing array. The sample trajectory signal produced is translated into a digital signal by the sampling circuit. The processor receives the digital sample trajectory signal for comparison with a known reference trajectory signal. The processor produces a verification signal if a threshold probability that the same fingertip generated both signals is exceeded.

Abstract: A method and apparatus for noninvasively measuring blood glucose levels provides an indirect, reagentless, differential, photoacoustic technique which responds to absorption in a thin surface layer. An excitation source provides electromagnetic energy which is utilized to irradiate the tissue, such as skin. The output of the radiation of the excitation source at the desired wavelength is coupled through a transmission device, such as a fiber optic bundle, which irradiates the electromagnetic energy onto the body surface. Upon irradiation, acoustic energy is generated by the absorption of the electromagnetic energy in a relatively thin layer of the sample to be measured, characterized by a heat-diffusing length. The acoustic energy is detected by the probe which includes a measuring cell, reference cell, window and differential microphone. Absorption of the light beam results in periodic heating of the tissue, at and near the tissue surface.

Abstract: A distributed amplifier topology with distributed feedback includes a plurality of amplifier stages, each of which includes a FET, MESFET or HEMT. A negative feedback network is provided with each amplifier stage which enables the gain of the distributed amplifier to be reduced by varying the negative feedback. An important aspect of the invention relates to the fact that the gain can be varied with virtually no affect on the bandwidth performance of the product and without significantly affecting the return loss, IP3 and noise figure performance of the device.

Abstract: A method is disclosed for efficiently transmitting large numbers of data channels through a satellite (24). The method uses a block encoder (28) that encodes the data channels with a block code to produce an encoded uplink data stream. A modulator (30) modulates the encoded uplink data stream. A transmit antenna (32) then sends the resultant modulated uplink data stream (34) to the satellite (24). The satellite uses a satellite demodulator (48) and a switch (50) to produce an internal data stream consisting of selected data channels in the uplink data stream (34). The internal data stream is fed into a convolutional encoder (52). The output of the convolutional encoder (52) is connected to a satellite modulator (54). The satellite transmit antenna (56) then sends the resultant modulated downlink data stream (58) to a receiver.

Abstract: A new electrical cryogenic connector system employs two printed circuit board type mating connectors (1 & 3), each containing a plurality of plated-on metal lines (5 & 6) running along the respective circuit boards in parallel, with the plated-on metal lines on at least one of the connectors being of Beryllium Copper material. The ends of the series of Beryllium Copper lines on one of the complementary circuit boards is formed into a pointed spring finger that is pointed toward the opposed circuit board. With the two boards sandwiched and pressed together with their plated on metal lines directly in line with and facing one another, the spring fingers compress and, under the spring force created by that compression, the spring fingers engage and maintain positive electrical contact with the corresponding conductor traces on the opposed circuit board. Ancillary to the described connector, a new method for constructing an electrical connector is also presented.

Abstract: A photosensitive photoresist material which is effective for use as an ion etch barrier layer after patterning. The photoresist composition includes the reaction product of a compound having the general formula R.sub.1 --COO--(CH.sub.2).sub.n --O--R.sub.2 and a silylating agent.

Abstract: A photodetector having improved responsivity includes first, second and third contact layers and first and second absorption layers. The first and second absorption layers are disposed on opposite sides of the first contact layer. The second contact layer is disposed on the first absorption layer and the third contact layer is disposed on the second absorption layer. The first contact layer has a first polarity. The second and third contact layers have a second polarity which is opposite the first polarity. Preferably, the first and second absorption layers are each made of a material having approximately equivalent electrical characteristics and the second and third contact layers are interconnected. Alternatively, one absorption layer is responsive to a first wavelength and another absorption layer is responsive to a second wavelength.

Abstract: A method and system is provided for real-time detection of important multiple pulsed or CW signals of varying amplitude and frequency, from a group of simultaneously intercepted wideband intermediate frequency (IF) channels. The method is implemented in a channelized receiver system with a parameter encoder which filters the IF signals in a time-shared mode by dividing the IF channel bandwidth into progressively decreasing sub-band levels, multiplexing the IF signals from each sub-band and analyzing the time multiplexed IF signals to obtain the IF signal parameters. The system is flexible with programmable parameters and has the ability to eliminate most of the spurious signals with high probability of interception of the real signals. Conventional pulse descriptor words, band limited pre-detection samples and time-frequency pulse images are output for subsequent analysis or tactical application.

Abstract: A method and apparatus for emulating instructions of one microprocessor ("legacy instructions") with instructions of another microprocessor with an incompatible instruction set which provides increased throughput relative to known emulation systems. In particular, the legacy instructions are translated into direct vectors to software routines for each legacy instruction. Rather than fetching the legacy instruction and interpreting the instruction in software, the emulation system and method in accordance with the present invention fetches the direct vectors to the software routines which emulate the legacy instructions. The legacy instructions can either be translated by way of software when the legacy memory is loaded or modified, or by way of hardware when legacy memory is accessed. By fetching the direct vectors, the need for software-based look-up tables for interpreting the legacy instructions is obviated.

Abstract: A new amplifier module construction enhances the manufacturer's ability to repetitively construct multiple copies of millimeter microwave amplifiers having performance characteristics that are consistent with one another, particularly in input VSWR ratio characteristic, and which performance characteristic do not significantly change following any necessary rework of the amplifier module, including any MMIC chip replacement. In this module, a waveguide to microstrip transition is formed of a backshort member that is separate from the metal base or cover and that backshort member is held pressed in place against the substrate by force exerted by the module's cover plate through a spring member against the exterior of the backshort member. The spring member is formed by a resilient compressible gasket.

Abstract: Apparatus, and a method for its use, for automatically verifying the identity of a person seeking access to a protected property, such as a car, room, building or automatic teller machine. The apparatus, which is disclosed in the form of a handheld fob (14), includes a sensor (16) for reading biometric data, such as a fingerprint image, from the person (12), and a correlator (28) for comparing the sensed data with a previously stored reference image (32) and for determining whether there is a match. If there is a match, the fob (14) initiates an exchange of signals with the "door" (10) that protects the property. Specifically, the fob (14) generates a numerical value, such as a cyclic redundancy code, from the stored reference image (32), encrypts the numerical value, and transmits it to the door (10) as confirmation of the person's identity. For further security, the person (12) registers this numerical value at each door (10) to which access is desired.

Abstract: A spacecraft includes a thruster coupled to an outward-facing portion of each solar array such that the thruster plume faces outward from the spacecraft. With the thruster located outboard of any erosion-sensitive surfaces on the spacecraft, the thruster exhaust is directed away from the spacecraft. Since canting of the thrusters is no longer required, the mounting of the thruster in the outward-facing portion of each solar array increases the effective Isp of the thruster. A thruster drive assembly is coupled to each solar array, adjacent to the thruster, for positioning the thruster such that any thruster exhaust is directed away from the spacecraft. A central supply tank is conveniently coupled to a central body portion of the spacecraft for providing a common propellant supply to each of the thrusters.

Abstract: A high precision pointing mechanism (10), particularly for use in space applications. The precision mechanism includes a motor assembly (26) connected to a displaceable elbow (24). A controller (166) determines a motor torque command (170) in accordance with a position error (168). The position error is used to generate proportional gain (172), derivative gain (182), and integral gain (194) compensation terms. The sum of the proportional compensation component (172) and derivative compensation component (182) is used to generate a proportional-derivative compensation component. The proportional-derivative compensation component is input to a hyperbolic tangent function (188), which substantially models the friction characteristic of the high precision pointing mechanism (10). The output from the hyperbolic tangent function (188) is used in combination with the proportional-derivative compensation component and the integral compensation component to generate the motor torque command (170).

Abstract: A satellite based telecommunications system having a multiple registration location register which enables a terminal to register with more than one earth station simultaneously, without any particular one of the earth stations knowing that the terminal is registered elsewhere. The multiple registration location register receives the registration information from each of the earth stations and records the information. This information is used by the multiple registration location register to re-route calls to an earth station that is providing coverage for the terminal. The multiple registration location register may consider many system factors, including satellite to earth station connectivity and satellite to terminal connectivity, in determining to which earth station it should route calls.

Abstract: A Schottky barrier diode and a method for fabricating a Schottky barrier diode that utilizes HBT active device layers. The Schottky barrier diode is formed with a vertically integrated profile on a GaAs substrate, with a subcollector layer and a collector layer. A suitable dielectric material is deposited on top of the collector layer. Vias are formed in the collector layer and subcollector layer for the barrier and ohmic contacts. The collector via is relatively deeply etched into the collector layer to lower the series resistance between the barrier and ohmic contacts, which results in relatively higher cut-off frequency performance.

Abstract: A method for multi-mode autonomous selection demodulation is disclosed. The method includes the step of providing a receiver with demodulation circuitry (110-112) capable of demodulating a plurality of waveform modulation techniques. The method also includes the step of receiving a modulated information waveform and a preamble associated with the modulated information waveform. The method also includes the steps of matching the preamble against a predefined set of patterns corresponding to a plurality of modulation techniques at the receiver and identifying a corresponding demodulation technique. Additionally, the method configures the demodulation circuitry (110-112) to apply the corresponding demodulation technique to the modulated information waveform.

Abstract: Apparatus, and a method for its use, for automatically verifying the identity of a person seeking access to a protected property that is remotely located with respect to the apparatus, such as a remotely located computer file or building alarm system. The apparatus, which is disclosed in the form of a handheld device (14) or other portable device (14'), includes a sensor (16) for reading biometric data, such as a fingerprint image, from the person, and a correlator (28) for comparing the sensed data with a previously stored reference image (32) and for determining whether there is a match. If there is a match, the device (14) initiates an exchange of signals over a communication network, with the "door" (10) that protects the property. Specifically, the device (14) generates a numerical value, such as a cyclic redundancy code, from the stored reference image (32), encrypts the numerical value, and transmits it to the door (10) as confirmation of the person's identity.