Abstract: An apparatus and method for filtering the effects of large amplitude signal fluctuations from elements of the cross-spectral density matrix of a detor array. The outputs of the array are sampled T times, and the values of each element of the matrix formed by using: ##EQU1## where Z.sub.li is the complex output of an sensor of the array at time i; Z*.sub.mi is the complex conjugate of the output of an array sensor at said time i; and k is an integer greater than 1. Because of the exponent k, small, relatively constant, terms will dominate, reducing the effect of large amplitude fluctuations. Preferably, the above value will be scaled according to: ##EQU2## which, besides being similarly filtered by the exponential terms, the resultant matrix element will have a magnitude corresponding to the actual power of the detected signal, after filtering.

Abstract: An optical method and apparatus particularly useful as an intensity modulation system, in which two phase modulators are placed in the loop of a Sagnac interferometer. Selective placement of the modulators, and the amplitude of any modulation signal input to the modulators, varies the bandwidth and frequency response of the system. In a preferred embodiment, the ratio of the optical distances of the modulators from interferometric midpoint, and the ratio of modulation signal amplitudes, is about 3:1, which serves to broaden and flatten the frequency response of the system.

Abstract: A spatial image separator includes a separating arrangement that separates an incident image pattern into a plurality of segments. The spatial image separator additionally includes a manner of relocating and selectively recombining a set of the segments toward at least one output position. This is accomplished in a manner which preserves information content while significantly improving energy utilization.

Abstract: The Intelligent Hypersensor Processing System (IHPS) is a system for the rapid detection of small, weak, or hidden objects, substances, or patterns embedded in complex backgrounds. providing fast adaptive processing for demixing and recognizing patterns or signatures in data provided by certain types of "hypersensors". This system represents an alternative to prior systems for hidden object detection by solving the problems encountered when attempting to detect hidden objects/targets in dynamic scenarios at real-time.IHPS accomplishes this by forming, a series of pattern vectors through the concatenation of the outputs of multiple sensors. Each sensor measures a different attribute of the system being observed, and has a consistent relationship to all the other sensors. The data stream form the sensors is entered into a processing system which employs a parallel-pipeline architecture. The data stream is simultaneously sent to two separate processor pipes.

Abstract: A filter, and method of the filtering, for increasing the signal to noise tio of relatively small and constant amplitude signals in the presence of relatively large and varying amplitude signals. The filter produces a filtered power level a.sub.z proportional to: ##EQU1## where x.sub.i are power realizations of the signal in a selected frequency bin, and i=1, 2, . . . , N, and z is a non-zero real number not equal to -1, 0, or 1, and is preferably positive. For positive z, because filtered power level a.sub.z depends on a sum of (x.sub.i).sup.-z, sum a.sub.z disproportionately favors smaller, more stable, signals.

Abstract: A scanning system for scanning in first and second dimensions a desired surface topology of a sample, the scanning device comprising: a light source for producing a collimated light beam; a first scanning device responsive to the collimated light beam from the light source for producing a first scanned beam in a first dimension with a constant optical path length; and a second scanning device coupled between the first scanning device and the sample for focusing and scanning the first scanned beam in a second dimension onto the surface region of the sample to cause the collimated light beam to scan the surface topology of the sample with a constant optical path length in each of the first and second dimensions of the desired topology of the sample. In a second embodiment of the invention, a beam of light is focused by a first lens before a scanner and the scanner is rotated.

Abstract: A receiver, especially useful for MMIC semiconductor communications circuits, in which plural mixers replace LRC filter networks to produce notched bandwidth filters. In a preferred embodiment, the input signal and a the output of a variable oscillator are mixed to produce a beat frequency. As an operator changes the desired frequency notch of the receiver, the output frequency of variable oscillator similarly changes to ensure that the beat frequency is the same regardless of desired frequency. Circuity downstream may be thus fixed, eliminating the need for large variable capacitors, which MMIC technology cannot fabricate in desirably small sizes.

Abstract: A Mach-Zehnder interferometer has electrodes configured to act as a microe transmission line. The optical waveguide arms have a reflective coating on their distal ends so that light is reflected back through the arms. The microwave transmission line is open-ended in a vicinity of the reflective coating so that microwave energy is reflected at the open end. Thus, the interferometer supports a traveling wave in a reflective configuration, and the distance over which interaction takes place can be effectively doubled.

Abstract: An optical intensity modulator which uses a Sagnac interferometer having an electro-optic phase modulator therein. An electric modulation signal is delivered to the modulator, and the latter is selected so that the phase velocity of optical and electrical signals are comparable in it. This causes the optical signal from one interferometer arm to copropagate through the modulator with the electrical signal, increasing interaction time with it, and causes the optical signal from the other arm to counterpropagate with the electric signal, reducing interaction time. In addition to phase modulating the optical signals by the electrical signal, the electro-optic effect in the modulator phase shifts the optical signals with respect to one another, permitting them to form a non-zero interference pattern, whose intensity corresponds to the electrical signal.

Abstract: A method and apparatus for transporting a positive ion beam to a distant target. An ion channel is created as a path to the target, and the beam injected into the channel at a mildly-relativistic beam velocity. Because the beam is mildly-relativistic, the electric field caused by its positive charge propagates well in advance of the beam, attracting free electrons in the plasma channel and pulling them into the beam along its axis of propagation. The current which is initiated by this precursor electron flow, is sustained during the duration of the beam, and is then a combination of the beam current and additional current carried by the electrons within the channel. As a result, a magnetic flux circulates annularly about the beam of a sufficient magnitude to pinch the beam.

Abstract: A method and apparatus for extracting an object from an image, in which one locates a pixel within the image (the "central" pixel), and then sequentially compares the brightness of neighboring pixels, proceeding outward from the central pixel. In so doing, one determines the largest dropoffs in brightness between neighboring pixels, and uses these to determine a brightness threshold for extracting pixels belonging to the object. In a preferred embodiment, one determines the threshold by comparing the largest dropoffs, identifies overlapping regions of brightness level common to all the dropoffs, and sets the threshold at the midpoint of the common overlapping region.

Abstract: An x-ray lithography device in which a beam of electrons interacts with a microwave field of a quasi-optical maser such as a quasi-optical gyrotron. This maser comprises a pair of spaced mirrors defining a quasi-optical cavity therebetween, with one mirror being provided with an orifice to permit extraction of the x-ray beam produced. A Bragg reflector is connected to the mirror orifice to reduce the microwave power loss from the device through the orifice. Electrons injected in the maser cavity are caused to "wiggle" by the interacting microwave field, which functions as an undulator, so as to produce a non-coherent x-ray beam that travels along the longitudinal axis of the cavity and exits through the mirror orifice.

Abstract: A system in which two circuits which are spatially mobile with respect to one another communicate with one another over a preselected range to identify themselves. So long as the communication remains, one of the circuits, called a detector, maintains the input/output of a third circuit enabled. Upon breaking communication, for example by one of the circuits moving outside the preselected range, input/output of the third circuit is disabled. In one embodiment, the third circuit is a computer workstation to which the detector is affixed, and the other circuit, called the agent, is worn or carried by an authorized user of the workstation. This permits the workstation to be available to the user while he is present, and become unavailable in general when he is not.

Abstract: A multiple quantum well spatial light modulator combines both optically addressed and electrically addressed portions on a single wafer. The electrically and optically addressed portions may be physically distinct or combined. To fabricate the modulator, a portion of an optically addressed multiple quantum well spatial light modulator is configured as an electrically addressed portion by pixellating that portion of the multiple quantum well wafer. The frequency of the applied voltage to the electrically addressed portion is increased such that the voltage switches faster than both the dark and illuminated screening time. The electrically and optically addressed portions may be combined or positioned side-by-side. The spatial light modulator has applications in a wide variety of low-cost, high performance pattern recognition systems. In one system, a first infrared beam impinges the electrically addressed portion of the modulator and picks up the pattern electrically written thereon (i.e., the template image).

Abstract: Disclosed are single electron digital devices, in which the screening lengths of individual device islands are between 0.5 and 1.0 islands. This range permits island occupancy to be bias independent, permitting the devices to hold or process digital information independent of device biases. This range of screening lengths can be effected by choice of device parameters which are sufficiently modest to permit practical fabrication of these devices.

Abstract: A apparatus and method for coherently stretching or compressing signals of nterest, i.e. without loss of information. A first, or tapping, Bragg cell has an acoustic signal launched in it which is modulated onto a laser carrier. The signal of interest is launched into a second, or signal, Bragg cell, and is similarly modulated onto the carrier exiting the first Bragg cell. Upon demodulation, the resultant signal, is the convolution of the two acoustic signals in the respective Bragg cells, but whose duration is either stretched or compressed according to the relative velocity between the acoustic signals in the two Bragg cells, and by the magnification of optics between the two cells. If the signal in the first Bragg cell is of such a short duration that it is effectively an impulse, the resultant signal is a coherently stretched or compressed replica of the signal launched into the second Bragg cell, i.e. the signal of interest.

Abstract: An apparatus using nuclear magnetic or quadrupole resonance to detect selected nuclei in a specimen (e.g., specimens containing a class of explosives or narcotics). The apparatus includes a pulsing unit to generate an RF pulse or a train of pseudo-random RF pulses used in stochastic NQR. Each of the pulses has an RF signal reaching a full amplitude within a quarter-cycle (substantially no pulse rise delay) and having a recovery delay of less than Q/.pi. cycles (substantially no recovery delay). The apparatus also includes a transmitter (e.g., a coil) to irradiate the specimen with a train of pseudo-random RF pulses and to detect after each pulse a resonance signal generated by the specimen in response to each corresponding pulse of the train of pseudo-random RF pulses. The pulsing unit has a capacitor connected to a DC power source by a first switch and connected to the coil by a second switch. When the first switch is closed, the DC power source charges the capacitor.

Abstract: A method and apparatus for producing the conductivity-mobility spectrum of an isotropic semiconductor material, and hence infer the mobility and concentration of carriers in the material. Hall voltage and material conductivity are measured at a plurality of magnetic field strengths, values of the spectrum estimated for each field strength, and the estimates numerically iterated to produce convergent values for the spectrum. In one embodiment, interim selected values of the spectrum are prevented from going negative, which increases the precision of the ultimate convergent values. In another embodiment, the iteration equations employ damping factors to prevent over-correction from one iteration to the next, thus preventing convergent instabilities. The preferred iteration is the Gauss-Seidel recursion.

Abstract: A method and apparatus for sustaining chaos in a system by using the natural dynamics of the system to redirect flow towards a chaotic region along unstable manifolds of basin boundary saddles by utilizing small, infrequent parameter perturbations. The perturbations are determined based on the location of an unstable state, which is used as a control reference. The location of the unstable state, which is unobservable, is estimated by calculating a theoretical branch connecting the current state of the system to the target unstable state.

Abstract: A continuous-time multiplier-integrator-multiplier circuit in which the integrator is a transconductance-C circuit. This permits the integrators to have long time constants despite being tightly fabricated on an integrated semiconductor chip. The multipliers can preferably be Gilbert multipliers, to improve circuit frequency response.