Abstract: The present invention involves a combination of active and passive optical or opto-electronic device alignment techniques. Passive alignment is used for two axial lateral directions and all three axial rotational directions (yaw, pitch and roll). In such passive alignment, only the substrate is micromachined with passive alignment structures. One-dimensional active alignment is then used for the remaining axial lateral direction.

Abstract: Telecommunication services are provided to subscriber-provided radiotelephones (50) residing inside an aircraft (20). Telecommunication services are provided while the aircraft (20) is flying and utilize the aircraft's air-to-ground communication system (48) to access a radiocommunication link (34). Base stations (40) residing in aircraft (20) are configured to transmit at least two independent overhead control data pilot signals (54, 58) in response to instructions from a single controller (44). The control data pilot signals (54, 58) capture and control the subscriber-provided radiotelephones (50). Controlling methods are employed to force autonomous registration of radiotelephones (50) and to instruct radiotelephones (50) to transmit at minimum power levels.

Abstract: An optical index switch including curved ridge waveguides. The cladding around the waveguides is selectively etched to produce tightly curved optical switches.

Abstract: An improved digital bidirectional communications transceiver in which the upstream and downstream portions of the frequency spectrum are allocated in response to transmission line conditions and impairments such as background noise, radio frequency interference (RFI), crosstalk and reflected signals. The movement of the upstream and downstream carrier frequencies are elastic in that they may be adjusted in near real-time involving methods for determining the signal quality parameter(SQP) of the received signal. The SQP is used to estimate the bit error rate (BER) margin on the received data and also takes into account the total signal to interference ratio (SIR), where the interference includes crosstalk, RFI, and residual echo from the neighboring upstream or downstream channel. Because the carrier frequencies of the upstream and downstream channels are being dynamically allocated, it is necessary to implement a robust carrier acquisition, recovery and lock algorithm.

Abstract: In the control system disclosed herein, multiple input data streams are processed or filtered to generate multiple output streams by a filter which combines efficient batch processing of a fixed number of older input samples with immediate direct processing of a varying number of current samples thereby to generate multiple output data streams which are based on essentially current input data as well as older input data reaching back for a time interval which varies periodically.

Abstract: A data communication network includes a network access unit for coupling one or more computer devices to the network. The network typically has asymmetric upstream and downstream data transmission rates. The network access device implements a method for acknowledging data packets. When a new packet is received by the network access unit from one of the computer devices, the new packet is placed in an outbound queue in the network access unit. When the new packet contains an acknowledgment, previous acknowledgment packets in the outbound queue that have the same source and destination addresses as the new packet are identified and discarded. Remaining packets are transmitted from the outbound queue in the network access unit. By discarding acknowledgment packets in the network access unit, throughput is increased.

Abstract: An interference analyzing system and method analyze interference in a dual mode system having a digital network overlaid on an analog network. The digital network includes portable units operating within digital cell sites; whereas, the analog network includes mobile units operating within analog cell sites. The interference analyzing system measures the amount of interference caused by and to the portable units, and the amount of interference caused by and to the digital cell sites. The system individually compares these interference amounts to a predetermined threshold. If either of the interference amounts exceeds the predetermined threshold, the system selects one of the analog cell sites for spectrum clearing and determines the amount of spectrum to be cleared from the selected analog cell site.

Abstract: The present invention is noise attenuation system and related method for suppressing noise generated by a noise source, such as a jet engine, contained in a housing. An impedance device is positioned in the housing to attenuate the amplitude of sound waves generated by the noise source propagating in one direction and to create a reflected sound wave. The reflected sound wave is out of phase with the sound waves propagating from the noise source away from the impedance device. The reflected sound wave destructively interferes with this sound wave to attenuate the amplitude.

Abstract: An apparatus is disclosed for machine learning of a pattern sequence which is derived from a plurality of inputs. The pattern sequence is predicted from learning rate parameters that are exponentially related to an incrementally calculated gain parameter for each input. The gain parameter are increased or decreased in real time in correlation with the accuracy of the learning process. The disclosed apparatus are advantageously utilized in signal processing, adaptive control systems, and pattern recognition.

Abstract: A method for remotely detecting at a ground station failed multiplexors and radio transceivers in an airborne telephone system is disclosed. Usage activity of the devices is predicted using a normalized gaussian distribution. A three prong test examines actual usage activity of the multiplexors and radio transceivers which is normalized and compared with that predicted utilizing a chi-square analysis with a specified confidence interval to detect abnormalities in the usage activity.

Abstract: An emergency call originates from a cellular radiotelephone (20) and communicates through one of A-side and B-side cellular systems. Upon receipt of the call, the cellular radiotelephone (20) is assigned a temporary substitute Mobile Identification Number (MIN) (100) by the receiving A-side or B-side cellular system MTSO (33). Upon termination of the emergency call, a call-back to the cellular radiotelephone (20) is routed to both of the A-side and B-side MTSOs (100), using the substitute MIN (100), by the Public Switched Telecommunications Network (36). Both A-side and B-side MTSOs (100) issue a page order message to cellular radiotelephone (20) by transmitting to the MIN (74). Paging order confirmation messages (78), conveying the MIN (74), are evaluated for a match with a unique Electronic Serial Number (76).

Abstract: In a telephone system wherein a number of distant terminals are each connected to a remote terminal and in which a number of remote terminals are each connected to a central office, a distant terminal includes a drop testing circuit for making sequential measurements on a plurality of customer telephones. The drop test circuit is included in a measurement system for providing condition responsive signals describing parameters of the telephone system, The drop test circuit includes circuitry such as scaling resistors, voltage sources, switching elements, and a multiplexed analog to digital voltage-sensing converter for providing digital data for transmission to the remote terminal or other more central location. The remote terminal comprises a computer based analyzer for interpreting, processing, and storing the data transmitted to it.

Abstract: A language-independent and segment free OCR system and method comprises a unique feature extraction approach which represents two dimensional data relating to OCR as one independent variable (specifically the position within a line of text in the direction of the line) so that the same CSR technology based on HMMs can be adapted in a straightforward manner to recognize optical characters. After a line finding stage, followed by a simple feature-extraction stage, the system can utilize a commercially available CSR system, with little or no modification, to perform the recognition of text by and training of the system. The whole system, including the feature extraction, training, and recognition components, are designed to be independent of the script or language of the text being recognized. The language-dependent parts of the system are confined to the lexicon and training data.

Abstract: A low cost and highly accurate sniper detection and localization system uses observations of the shock wave from supersonic bullets to estimate the bullet trajectory, Mach number, and caliber. If available, muzzle blast observations from an unsilenced firearm is used to estimate the exact sniper location along the trajectory. The system utilizes a distributed array of acoustic sensors to detect the leading edge of a projectile's shock wave and the muzzle blast from a firearm. The detection of the shock wave and muzzle blast is used to measure the wave arrival times of each waveform type at the sensors. This time of arrival (TOA) information for the shock wave and blast wave are used to determine the projectile's trajectory and a line of bearing to the origin of the projectile. A very accurate model of the bullet ballistics and acoustic radiation is used which includes bullet deceleration.

Abstract: A cellular communication system (10) includes any number of land stations (12), each of which controls a cell (14). When channels are assigned to cells (14), a figure of merit which predicts potential voice quality, such as C/I, is determined (34) for each channel/cell assignment. The assigned channels and associated figures of merit are distributed to corresponding land stations (14) to make channel-to-cell assignments. When a call arises in a cell (14) a channel is selected for assignment to the call. The channel is selected from channels assigned during the channel-to-cell assignment phase. A channel assignment algorithm (68) ensures that potentially lower quality channels (20) are the least used channels at the cell (14). When potentially lower quality channels (20) are assigned to calls, the calls are handed off to potentially higher quality channels (18) as soon as potentially higher quality channels (18) become available.

Abstract: A method and apparatus is disclosed for enhancing the security of a message sent through a network server from a client computer to a destination server. A secure connection for receiving and transmitting data is established between the client computer and the network server. Using client-identifying information and a secure authentication protocol, the network server may then obtain client-authentication information from a validation center. The client-authentication information is transmitted to the client and erased from the network server. The network server then receives the client-authenticating information back from the client with an accompanying message for the destination server. The network server may use the client-authenticating information to obtain permission data from the validation center for use in accessing the destination server.

Abstract: A unified communication system is designed using an agreed upon transmission protocol between different carriers. The protocol is used to allow the automatic gathering of administrative data (such as trouble reports) from diverse locations within a sending network, using the proprietary administration data language and structure of that network. The gathered data is transported using the transmission principle to a single point of contact at a receiving network and translated into a data structure proprietary to the receiving network and thus presented to the proper system for action within the receiving system.

Abstract: A multiple mode, personal, wireless communications system exists within a radiotelephone network serving general customers and provides additional services to a select group of customers. The system uses handsets (32) which automatically switch between a standard cellular radiotelephone mode of operation (1901) and an enhanced cordless mode (1420) when the handsets (32) are within range of pico cells (26) that are interconnected to the public switched telephone network (20). Each pico cell is controlled via a framework of overlay cells (10b) that operates independently of the radiotelephone network and uses a unique control protocol on a small number of reserved cellular channels. Each pico cell consists of a spectrally dynamic, non-capturing, frequency agile, multi-purpose base station (26) provided at customer-selected locations to cooperate with the overlay cell framework. Each pico cell is capable of supporting multiple handsets (32) and using low power operation that achieves limited coverage.

Abstract: A reconfigurable ring architecture for RF transport over fibers which eliminates the need for multiple pairs of fibers to serve multiple microcells and the need for backup communications lines as a result of system failure due to a fiber break. The ring architecture has a plurality of remote units which are interconnected to a host unit in a serial fashion. The host unit transmits signals to the plurality of remote units and receives signals from the plurality of remote units. Each of the remote units having photodetectors for receiving the transmitted signals and an antenna/transmitter for receiving other signals from another source; a splitter for splitting the transmitted signals into two parts, one part of the signals being output from the remote unit and the other part of the signals being transferred to adjacent remote units and then back to the host unit; and a transmitter for transferring the other signals from the remote unit to adjacent remote units and then back to the host unit.

Abstract: A multiple mode, personal, wireless communications system exists within a radiotelephone network serving general customers and provides additional services to a select group of customers. The system uses handsets (32) which automatically switch between a standard cellular radiotelephone mode of operation (1901) and an enhanced cordless mode (1420) when the handsets (32) are within range of pico cells (26) that are interconnected to the public switched telephone network (20). Each pico cell is controlled via a framework of overlay cells (10b) that operates independently of the radiotelephone network and uses a unique control protocol on a small number of reserved cellular channels. Each pico cell consists of a spectrally dynamic, non-capturing, frequency agile, multi-purpose base station (26) provided at customer-selected locations to cooperate with the overlay cell framework. Each pico cell is capable of supporting multiple handsets (32) and uses low power operation that achieves limited coverage.