Abstract: A laser range finder including a receiver for detecting a return pulse and providing an output signal indicative thereof, a single integrated circuit digital range counter chip connected to receive the output signal from the receiver, a power supply unit for powering the receiver and range counter chip, and a single-chip microcontroller for selectively sequencing application of power to the receiver and to the range counter chip, for controlling laser firing, and for automatically recalibrating the receiver.

Abstract: A laser pump cavity assembly having a laser rod with a ground outer surface positioned concentrically within an annular jet sleeve which is, in turn, positioned concentrically within an annular outer sleeve. The outer sleeve is coated with a dielectric coating having slits therein arranged to receive focused optical pump radiation from respective laser diode arrays, the pump radiation being transmitted through the outer sleeve and jet sleeve to excite the laser rod. The jet sleeve is positioned to define cooling fluid chambers between the outer sleeve and the jet sleeve, and between the jet sleeve and the laser rod, and is provided with a series of jet holes for directing cooling fluid to impinge perpendicularly on the laser rod. The end faces of the jet sleeve and outer sleeve are further coated with dielectric material to enhance the efficiency of the device. The cooperating end caps which mount the outer sleeve, jet sleeve, and laser rod employ a number of advantageous self-aligning and sealing features.

Abstract: A digital cellular communication system in which fixed subscribers and mobile subscribers share base transceiver stations, base station controllers and mobile switching centers to communicate with the switched telephone network. Mobile subscribers communicate using any cellular radio protocol, while the fixed subscribers communicate via a multi-subscriber unit (MSU) using the inventive air interface. The MSU system uses digital speech interpolation to transmit speech spurts between subscribers and the switched telephone network. Preferably, time division multiple access channels in a digital speech interpolation pool are allocated and deallocated on a speech spurt basis.

Abstract: An apochromatic grism (42) includes a first prism (48) with a second prism (50) disposed adjacent to it. A grating (44) is adjacent to the front surface of the first prism (48) and the Abbe number and dispersion coefficient of the grating are chosen such that the primary and secondary angular spread for a given spectral band is approximately zero. The apochromatic grism is a simple and compact device with minimal amounts of residual chromatic and anamorphic aberrations.

Abstract: An arrangement (10) for mounting a night vision enhancement system to a vehicle (1010). The invention is adapted for use with a night vision enhancement system having an infrared camera (14) and a display (587). In the preferred embodiment, the invention (10) includes a mounting mechanism (16) disposed at a front end of said vehicle (1010) for retaining the camera (14). Optionally, a door (42) is included for protecting the camera (14). The door (42) is actuated on command between open and closed positions by a solenoid (44) attached to the frame of the vehicle on one end and to a linkage (48, 49) on the other. The linkage (48, 49) allows the door (42) to pivot in response to the movement of the solenoid plunger (45). The camera (14) is retained in an upside down orientation by a bracket (16) which is attached to the frame of the vehicle.

Abstract: A modular signal processing architecture adapted for use with a focal plane array of detectors. The inventive architecture includes an analog signal processing module (42) for adjusting signals from the focal plane array (12). A nonuniformity correction module (44) provides signal adjustment parameters to the analog signal processing module (42) for each of the detectors in the array (12). A control module (80) provides control signals to each of the modules in the system as required for a desired system configuration. In a specific embodiment, the control signals are communicated via programmable registers on each module. Software running on the system control module provides the control signals to the programmable registers to reconfigure the system in response to the addition of modules thereto. Hence, additional modules may be easily incorporated into the system without a costly redesign of same.

Abstract: A power management system for a laser range finder including a microcontroller which controls the supply of power by a series of linear regulators to analog electronics and digital electronics such that the respective electronics units are powered only during intervals when they require power during operation of the laser range finder. The linear regulators and a laser firing pulse generator circuit are powered by simplified DC/DC converter circuitry which is, in turn, supplied with power by a solid state front end circuit subject to control by the microcontroller and which includes first, second, and third transistors providing reverse voltage protection, overvoltage protection, and reduced power consumption.

Abstract: A cellular base station receiver uses a digital signal processor to decode receiver code words in an inner Reed-Solomon code. A list of code word estimates is generated by making different symbol erasure combinations. An outer cyclic redundancy code operates as an error detector for the word estimates. When a code word estimate is found to be error-free, it is accepted for output.

Abstract: An echo canceller for use in fixed-wireless telephony networks using low-rate packetized speech coding and DSI is disclosed. An adaptive filter is used to cancel an echo signal of a far-end signal introduced at the near-end by operating to provide a replica signal to cancel the echo signal. The replica signal is updated in the absence of a near-end talker signal presence of near talker signal is detected using an estimated echo-residual loss. The echo replica signal updating process is frozen upon the detection of double-talk. Residual echoes are suppressed without the use of non-linear processing. A residual suppression flag detection and a voice activated switching device are used to detect the absence of near-end signals. The switching device is opened if the signal to be transmitted is not a near-end signal or is noise.

Abstract: A pattern and a method of establishing a pattern of microcell base station antennae in dense urban areas. The base station antennae are each configured to transmit on one of several sets of frequencies, and are placed at intersections on a grid of horizontally parallel and vertically parallel streets. The pattern distributes the antennae in two separate repeating sequences running diagonally on the grid. By using tall buildings between the streets as propagation blockers, the pattern optimizes the use of a limited number of allocated frequencies and minimizes co-channel and adjacent channel interference.

Abstract: A device and method for detecting and suppressing double-talk in a cellular mobile unit employ a cellular transceiver; a receive signal path; a transmit signal path; and a double-talk detector. The double-talk detector determines a receive slope of a receive signal, and determines a transmit slope of a transmit signal. The double-talk detector further determines a difference slope of a difference signal that is determined by evaluating differences between the receive signal and the transmit signal. Finally, the double-talk detector generates a double-talk flag signal in the event the transmit slope indicates an increasing transmit speech power, and the receive slope and the difference slope indicate a prescribed relationship between the changes in the receive speech power and the difference power.

Abstract: A method for encoding a signal that includes a speech component is described. First and second linear prediction windows of a frame are analyzed to generate sets of filter coefficients. First and second pitch analysis windows of the frame are analyzed to generate pitch estimates. The frame is classified in one of at least two modes, e.g. voiced, unvoiced and noise modes, based, for example, on pitch stationarity, short-term level gradient or zero crossing rate. Then the frame is encoded using the filter coefficients and pitch estimates in a particular manner depending upon the mode determination for the frame, preferably employing CELP based encoding algorithms.

Abstract: A cellular base station (10) in a digital cellular system employs transmitting circuitry in which voice signals (15) are processed at a low frequency level (12) into two separate paths. A first of the low frequency signals is variably delayed (20), and the first and the other low frequency signals are upconverted to radio frequency level (16,22) for transmission over independent time-spaced transmission paths (26,28) to cellular receivers. A receiver downconverts and demodulates the radio frequency diversity signals, and then combines the demodulated diversity signals to generate an equalized combination diversity signal for receiver output processing.

Abstract: A method of encoding speech using a fixed-point processor. The method treats the signal as floating point, while operating on each sample of the signal as fixed point. The disclosed method achieves precision similar to that of conventional floating point and may be rapidly executed on a fixed point processor.

Abstract: A data transfer device for transferring data between a plurality of digital signal processors in a system utilizing time division multiple access techniques. The data transfer device includes a system controller coupled to a bus network, a plurality of dual port random access memories, and a direct memory access controller. Each dual port random access memory device includes a first input/output port coupled to one of the plurality of digital signal processors, and a second input/output port coupled to the bus network. Each of the plurality of digital signal processors can access the dual port random access memory device coupled thereto during a first predefined time within a TDMA cycle. During a second predefined time period within the same TDMA cycle, the direct memory access controller, under control of the system controller, transfers data directly between the dual port random access memory devices.

Abstract: The present invention provides for carrier offset tracking which is particularly well suited for use in a receiver for digital cellular mobile telephones. The tracking includes storing samples received in time slots, generating estimates of the transmission channel impulse response, recording two samples of each tap of each channel impulse response estimate, generating frequency offset estimates from the phase difference in each time slot between the samples, combining this plurality of frequency offset estimates to generate a precise frequency offset estimate, and adjusting a controllable frequency source to compensate for the precise frequency offset estimate. Time-reversed operation further enhances performance and permits implementation with reasonable complexity for a standards compliant mobile receiver.

Abstract: A mechanism for handing off between an overlay cell (48) and an underlay cell (50). The underlay cell (50) is smaller than and has a common area with the overlay cell. A threshold level (RSSI-THP) is established which corresponds to the sum of a nominal threshold level (RSSI-U) and a value obtained by subtracting the current attenuation level (MT) from the minimum attenuation level permitted by the underlay cell (MU). If the RF signal level of the serving cell (RSSI-SRV) is greater than the established threshold level (RSSI-THP), the mobile unit is handed off to the underlay cell (50), if not already in that cell; and handed off to the overlay cell (48) if equal to or less than the established threshold level (RSSI-THP), if not already in that cell.

Abstract: An AFC system and method of detecting and compensating frequency drift in the carrier frequency of a Gaussian filtered Minimum Shift Keying (GMSK) signal by demodulated frequency compensated samples of the received signal and calculating a frequency compensation angle based upon the demodulated frequency compensation samples. The compensation angle is fed back to the frequency compensator and error detector and used to calculate the error signal.

Abstract: A method and apparatus utilizing the techniques of frequency shifting and filtering for converting an input signal having a desired signal at intermediate frequency and an undesired DC offset to a baseband frequency signal in which the undesired DC offset is eliminated. The apparatus includes a first multiplier for multiplying the input signal by a signal having substantially the same intermediate frequency plus an offset frequency (.DELTA.f) to produce a first output signal wherein the desired signal is shifted in frequency to the offset frequency (.DELTA.f) and the undesired DC offset is unaffected. The apparatus also includes a second multiplier coupled to the first multiplier for multiplying the first output signal by a signal having substantially the same offset frequency (.DELTA.f) to produce a second output signal having the desired signal shifted to baseband frequency and the undesired DC offset shifted in frequency to the offset frequency .DELTA.f.