Abstract: A method and apparatus for the fast acquisition of GMSK-modulated signal for CDPD (Cellular Digital Packet Data) applications wherein the frequency offset and time of arrival of the data sequence are quickly determined. The computational burden is reduced by roughly estimating the frequency offset using an operation insensitive to timing uncertainty and roughly estimating the time of arrival using an operation insensitive to frequency offset using the roughly estimated frequency offset and time of arrival to construct a small two dimensional array to determine the final frequency offset and time of arrival.

Abstract: The present invention provides a method and device for locking onto a carrier signal located within a frequency band of a digitally modulated analog signal. More particularly, the method includes the steps of: dividing the frequency band into a plurality of segments, measuring a signal quality value for each of the segments, selecting one of the segments based on the measured signal quality values, and sweeping the selected segment using front-end circuitry in a receiver adapted to lock onto the carrier signal. The device according to an embodiment of the present invention includes a controller, a signal quality measurement unit, and a receiver including a front-end circuit. The controller executes a program that includes a first routine for dividing the frequency band into a plurality of segments. The measurement unit responds to the controller and measures a signal quality value for each of the segments.

Abstract: Apparatus and method for conveying information from an object by delayed reflection of an interrogating ultra-high range resolution radar signal which is digitized into a series of programmable spaced pulses by an electronic license plate circuit. The electronic license plate includes a plurality of unique programmable delay lines connected through a coupler network to an antenna.

Abstract: A controllable infrared filter (22) includes a quantum well filter unit (24) operable to absorb infrared energy at a selected wavelength. The quantum well filter unit (24) has a quantum well layer (26) made of an infrared transparent semiconductor mate rial and a barrier layer (28, 32) of another infrared transparent semiconductor material epitaxially deposited on each side of the quantum well layer (26). There is structure for controllably introducing charge carriers into the quantum well layer (26), which may utilize a source of electrons from other semi conductor layers (36, 38) and an applied voltage, or may utilize a laser (76) that generates charge carriers in the quantum well layer (26). The filter (22) further includes a lens (44, 46) or other optical system for directing infrared radiation through the first barrier layer (28), the quantum well layer (24), and the second barrier layer (32). Fixed band pass optical filters may be used in conjunction with the controllable quantum well filters.

Abstract: An undersea vehicle storage and ejection system includes a capsule having a cavity therein adapted to store and launch a vehicle. The capsule has an opening at one end for passage of the vehicle therethrough. A closure member is suitably adapted to be mateable with the housing at the opening to seal the cavity. A rocket unit is incorporated within the capsule to remove the closure member at launch. The closure member includes a sealing arrangement for withstanding the hydrostatic pressure when the system is in the undersea environment of use and block the entry of sea water into the cavity. The rocket unit, when ignited, rapidly builds up pressure within the capsule to a level exceeding the external hydrostatic pressure on the cover, thereby removing the cover so that the vehicle may be launched.

Abstract: A dual polarization array that comprises horizontal polarization and vertical polarization arrays, combined with an efficient waveguide-fed standing wave feed array. The vertical polarization array comprises an offset, resonant, iris-fed, centered longitudinal-shunt-slot, standing wave array. The horizontal polarization array comprises a flared dipole fed by a longitudinal, shunt-slot, standing wave array. The waveguide-fed standing wave feed array is comprised of a plurality of waveguides that separately feed the horizontal polarization and vertical polarization arrays. The horizontal polarization array comprises a first plurality of radiating waveguides laterally disposed adjacent to each other that are separated by a first plurality of gaps. Each waveguide comprises a plurality of radiating flared dipoles disposed adjacent to a respective plurality of longitudinal radiating shunt slots.

Abstract: A bomb damage assessment system that is carried by a weapon and released to provide imagery of a bombed area before and after bomb delivery. The system comprises a glider that is releasably secured to the weapon that includes tracking and guidance electronics for programmably controlling the flight thereof. An imaging system is disposed in the front end of the glider and a deployable ballute is disposed at the rear end thereof. A data link is provided for transmitting images to a command center for review. The system provides imagery of a target area before, during and after weapon impact. Television or infrared cameras may be used for day or night missions. As a target area is approached, the glider is released, is decelerated by the ballute, wings are unfolded, and the ballute is released, resulting in an aerodynamic vehicle that flies much slower than the weapon. The imaging system tracks the weapon to impact. The explosion of the weapon produces a hot spot that is tracked by the imaging system.

Abstract: An autonomous bomb damage assessment system that is piggybacked to a bomb to provide imagery of a bombed area immediately after bomb delivery. The bomb damage assessment system comprises a housing that is releasably secured to the bomb. An imaging system is disposed at one end of the housing and a folded inflatable balloon is disposed at the other end of the housing. An inflation device is provided for inflating the balloon with a lighter-than-air gas such as helium. A proximity fuze is used to sense the location of the ground, for causing the system to be ejected away from the bomb shortly before bomb impact, and for causing the inflation device to inflate the balloon. A data link is disposed in the housing for transmitting images derived from the imaging system to a remote location. The present invention provides imagery of a bombed area immediately after bomb delivery. The lighter than air characteristic of the system allows a dwell time over the bombed area so debris and dust can settle.

Abstract: A digital discontinuous cellular communication system has a transmitter that transmits two frames of data following detection of voice inactivity. A receiver includes a comfort noise generator that uses the two frames of data to output noise to the speaker during period of voice inactivity. The comfort noise generator includes synthesis codebook with samples scaled by actual background noise and excitation codebook with samples filtered and scaled by the background noise that are combined to produce comfort noise having attributes and loudness level of the received background noise prior to interruption of transmission. The scaled signals are weighted to vary the loudness level and spectral attributes.

Abstract: The present invention provides for sample timing adjustment using channel impulse response which is particularly well adapted for use in a receiver for digital cellular mobile telephones. The sample timing adjustment includes storing samples in time slots, generating estimates of the transmission channel impulse response, and using a subset of the samples received during the time slot, and generating error measurements of the degree to which the estimated channel impulse responses match the actual channel impulse responses. The different measures use simultaneously recorded samples having different time offsets. At least one sample used for each measure is advanced in time and one sample used for each measure is retarded in time relative to the samples used for generating the first measure. Then, a sample time setting that minimizes the error measurement is determined and the sampling is adjusted to reflect the newly determined sample time setting.

Abstract: A video image processor (100) for processing video images performing the steps of generating video images (103) with a multi-spectral video source (102), converting analog color data contained in the generated video images (103) to digital color data for subsequent signal processing, extracting the digital color data from designated areas of the generated video images and utilizing the extracted digital color data for identifying a color distinguishable from a background color. Thus, the video image processor (100) processes the generated video images and has an intrinsic immunity to the effects of shadows by exploiting multi-spectral color information to distinguish, for example, a passing vehicle from the roadway 116. In a preferred embodiment, the video image processor (100) includes a multi-spectral video source (102) for generating the video images.

Abstract: A method and circuit for synchronizing input data with a sample clock in which, for each sample clock cycle, the position of input data transitions relative to an acceptable neutral zone is detected. The neutral zone is of predetermined time duration and is positioned in a predetermined location relative to the active edge of the clock signal. If the transition occurs during the neutral zone no corrective action is warranted. If the data transitions move beyond the neutral zone, into a predetermined time interval on either side of the active edge, this event is captured and used by control logic to effect a return of the data transitions to a location within the neutral zone.

Abstract: An active impulse magnetometer includes a magnetic field transmitter which generates a low frequency magnetic impulse waveform. A separate magnetometer receiver responds to the transmitted waveform, and produces a receive waveform which is transformed by a Fast Fourier Transform device into the frequency domain. The transformed signal is processed to indicate the presence of any detected objects.

Abstract: A symbol timing recovery method and device which aligns the received data with a free-running symbol clock such that the aligned data sampling error is minimized. The symbol timing recovery process consists of detecting the timing phase error between the transmitters symbol clock and the receiver symbol clock, filtering the error, and then using the filtered error signal to control a block which changes the phase of the data relative to the timing reference signal. A data zero-crossing phase error detector drives a loop filter whose most significant bits form the address of the FIR coefficient ROM, which allows the FIR to interpolate data at sub-symbol resolution. The FIR coefficients are then used to synchronize the received data with the receiver clock.

Abstract: A multimedia codec for a frame relay network. Multiple information media from different sight equipment is converted to a standard packet for transmission over said frame relay network. Incoming frames are processed on a priority basis and stored in an elastic buffer. Tests of pointers are kept for each media type identifying the location in the elastic buffer of the various packets for the different media. Applications running in the frame relay processor retrieve the stored media data and forward it to a digital signal processor connected to respective terminal equipment.

Abstract: An article (22) is coated with a cermet coating (20) by first roughening and oxidizing the surface to be coated. A mixture is formed of a metallic powder having a mean particle size of less than about 5 micrometers, and a ceramic powder having at least some of the particle of a size less than the mean particle size of the metallic powder. The mixture of the metallic powder and the ceramic powder desirably has a coating coefficient of thermal expansion of about that of the article coefficient of thermal expansion after firing. The mixture of metallic and ceramic powders is slurried and applied to the prepared surface (24) of the article (22), preferably by spraying. The coated article is heated to an intermediate temperature to vaporize the carrier liquid, and thereafter to high temperature to sinter the coating.

Abstract: Bonding of polystyrene foam details together to produce lost foam molds suitable for casting metallic details is accomplished by coating one of the two mating surfaces of the parts with a phenol-formaldehyde adhesive. The two parts are joined together and the mated assembly is placed in a microwave oven. Exposure of the assembly to microwave energy for a pre-selected period of time effects the bonding.

Abstract: The photo-sensitive detector region of conventional Impurity Band Conduction (IBC) detector (also known as a Blocked Impurity Band [BIB] detector) is divided into a wide detection (or collection) region and a narrow gain region by means of tailoring the doping profile. The narrow gain region is that portion of the photo-sensitive detector region closest to the blocking layer, where the electric field is the largest, whose As concentration is made smaller (in the range of 2 to 5.times.10.sup.17 cm.sup.-3) to increase the impact ionization coefficient by decreasing the electron scattering. The wide detection region is that portion of the photo-sensitive detector region furthest from the blocking layer, where the electric field is smallest and the As concentration is larger (in the range of 5 to 8.times.10.sup.17 cm.sup.-3) to decrease the impact ionization coefficient by increasing the electron scattering.

Abstract: Chemically-etched and or sputtered CdTe surfaces are exposed to UV excimer laser radiation at a fluence ranging from about 15 to 75 mJ/cm.sup.2, followed by either a low temperature (<300.degree. C.) thermal anneal or exposure of the CdTe surface to UV excimer laser radiation at a fluence lower than the threshold fluence. This procedure provides clean, stoichiometric, and well-ordered CdTe surfaces.

Abstract: Plasma processing treatment characteristics of an object are determined nondestructively, prior to plasma processing the object, by placing an indicator layer over at least a portion of the plasma processing surface of the object, so as to generally conform to the shape of the surface. An electrically conductive grid is placed over the indicator layer, and made electrically common with the object. The indicator layer is implanted through the conductive grid, and changes properties responsive to the plasma processing treatment. The implanted indicator layer is thereafter analyzed to determine the treatment characteristics of the indicator layer. Plasma processing spatial distribution and total dosage are determined nondestructively from this information and used to establish the plasma processing program for the object and adjust the plasma processing apparatus as needed.