Abstract: Consistent with the present disclosure, a photonic integrated circuit (PIC) is provided that has 2 N channels (N being an integer). The PIC is optically coupled to N optical fibers, such that each of N polarization multiplexed optical signals are transmitted over a respective one of the N optical fibers. In another example, each of the N optical fibers supply a respective one of N polarization multiplexed optical signals to the PIC for coherent detection and processing. A multiplexer and demultiplexer may be omitted from the PIC, such that the optical signals are not combined on the PIC. As a result, the transmitted and received optical signals incur less loss and amplified spontaneous emission (ASE) noise. In addition, optical taps may be more readily employed on the PIC to measure outputs of the lasers, such as widely tunable lasers (WTLs), without crossing waveguides.

Abstract: Plating rack for releasably holding parts in a plating process, as well as processes for fabricating and using such a rack, including spring members mounted to a frame which releasably hold plate-shaped parts from the opposite side edges of the parts in a manner permitting the part to move sufficiently, without disengagement, when immersed in an agitated plating fluid such that plating occurs on all the exterior surface regions of the plate and scarring is avoided.

Abstract: A method of selecting allocated communication channels for use by a cellular auxiliary personal communication system (CAPCS) comprising periodically collecting relative signal strength indication (RSSI) measurements for all allocated communication channels, periodically determining the estimated expected probability of non-interference for each allocated communication channel based on the relative signal strength indication measurements and selecting an available allocated communication channel having the highest estimated expected probability of non-interference for use by the CAPCS system. The relative signal strength indication measurements are made on the allocated communication channels by measuring the signal on the allocated communication channel when no call is being carried by the CAPCS on that channel.

Abstract: A system which improves coverage in overlapping coverage areas between two type-A or type-B cellular radio telephone systems is able to direct a subscriber unit in the overlapping coverage area to the home or primary system, thereby minimizing the subscriber unit's roaming-type expenses. The system includes a control channel receiver, a control unit, and a control channel transmitter/receiver pair, in combination with a transmit/receive antenna. The system transmits a control channel, which is associated with the home system, into the overlapping region. The control channel is intended to be the strongest channel in that region. Any subscriber units in the region associated with the home system which respond to that control channel will be directed to other control channels associated with the home system. Those subscriber units will receive service from the home system, as opposed to the foreign system which may provide other strong control channels in the overlapping coverage area.

Abstract: A booster usable in a radio telephone communication system can amplify and repeat both analog and digital representations of communications. The unit monitors control channel communications going to subscriber units and reverse control channel responses from subscriber units. When a digital traffic channel assignment is detected, the booster directs the subscriber unit to a different traffic channel pair. The booster communicates with the subscriber unit on the traffic channel pair assigned by it to the subscriber unit. The booster communicates with the cell site on the channel pair assigned by the cell site. Digitized communications from the subscriber unit are amplified only during the associated time intervals. Hence, other communications in different time intervals on the same message channel are not effected. Analog conversations and other message channels can be simultaneously boosted and retransmitted.

Abstract: A cell extender for use in digital cellular telephone systems comprises a control module, and scanning module, and several traffic modules. The control module bidirectionally repeats the donor cell site control channels. Voice modules therein bidirectionally repeat selected donor traffic channels for mobiles. The voice module amplifies and translates the Reverse Digital Traffic Channel RDTC (transmitted by the mobile). The voice module reframes the Forward Digital Traffic Channel, and advances its timing such that RDTC signals transmitted by the mobile and repeated by the cell extender arrive at the donor with the correct timing alignment. The timing advance compensates for RF path propagation delay between the donor and the cell extender, and for any additional delay through the cell extender. If the voice module determines that the mobile is leaving the cell extender coverage area, it sends a hand-off message returning the mobile to the assigned donor traffic channel.

Abstract: An apparatus and method which can provide a private cellular system within an area already served by a public cellular system include a receiver for receiving RF control signals from the public system. The public system control signals are converted to saturation level control signals from the private system. Subscriber units to be serviced by the public system are directed thereto. Those associated with the private system can be serviced directly.

Abstract: A system and method for handing back a movable transceiver to a different cell site from the original cell site includes circuitry for sensing signals from the movable transceiver which are transmitted on a modified frequency as well as circuitry for translating those signals back to their originally assigned frequencies without changing the detected field strength of the signal, in combination with circuitry for forwarding the translated signals to the different cell site for hand-off evaluation. The method includes sensing the received signals, translating the received signals to an originally assigned frequency based on either a fixed offset or other provided information concerning the translation along with a step of continually updating those frequencies which are to be retranslated.

Abstract: A diversity receiving apparatus includes first and second antennas and circuitry for selecting one antenna or the other. Control circuitry analyzes signal strength received from the selected antenna and determines when the antennas should be switched. The antennas are switched when the received signal strength falls below a running average thereof; the received signal strength falls below a threshold value; or a predetermined time has elapsed since the antennas have been switched. The antennas are switched when the received signal strength falls below a running average thereof; the received signal strength falls below a threshold value; or a predetermined time has elapsed since the antennas have been switched.

Abstract: An apparatus for detecting excessive output power from a cellular radio telephone system booster includes input circuitry for receiving incoming radio frequency signals from a mobile source. Amplifiers are provided for amplifying the radio frequency signals either directly or by means of intermediate frequency channels. The output power amplifiers have variable gain. Circuitry detects when the transmitted radio frequency signals exceed a predetermine threshold and reduce the amplifier gain accordingly.

Abstract: A diversity receiving apparatus includes first and second antennas and circuitry for selecting one antenna or the other. Control circuitry analyzes signal strength received from the selected antenna and determines when the antennas should be switched.

Abstract: A power supply system is enclosed in a housing. A disk drive receptacle is arranged in the front of the housing, and a power supply and card cage for the microcomputer are laterally arranged at the rear of the housing. The front and rear of the housing are air permeable for cooling air. A power supply control circuit, for control of the power supply, controls a solid state relay in series with the power input to the power supply. The power supply control circuit also generates control signals, indicating pending power failure, for the microcomputer arranged in the card cage.

Abstract: A power supply control circuit, for control of the power supply, controls a solid state relay in series with the power input to the power supply. The power supply control circuit also generates control signals, indicating pending power failure, for the microcomputer arranged in a card cage.

Abstract: A system for coupling a plurality of telephones or local units to a remote land line telephone system includes a line interface associated with each of the telephones or local units. Each of the line interfaces is in turn coupled to an audio switch matrix. Outputs and inputs to and from the audio switch matrix are coupled to a 4 to 2 wire hybrid, a tone interface hybrid and a computer based control unit. The control unit includes a programmed microcomputer with interface circuits enabling it to communicate with and to control the line interfaces and the audio switch matrix. The computer also includes interface circuits enabling it to communicate with and control a radio transceiver. The radio transceiver is in radio frequency communication with a corresponding radio transceiver remotely located and coupled to the remote land line telephone system. Communications with the remote land line telephone system can be initiated by any of the local units.

Abstract: Process for preparing a heteropolysaccharide from strain NCIB 11883 and use of the latter e.g. as viscosity modifier in an aqueous system such as completion fluids, work over fluids, stimulation fluids, and preferably in drilling fluids and use in connection with well-treatments, and enhanced oil recovery.

Abstract: A binary up/down counter stage particularly suitable for CMOS implementation. The counter stage includes an exclusive OR gate having a first input for receiving a toggle signal, a flip-flop having a data input coupled to the output of the exclusive OR gate and Q and Q outputs, the Q output of which provides the stage output and a feedback to the second input of the exclusive OR gate, and a multiplexer having first and second inputs coupled to the Q and Q of the flip-flop respectively, the output of the multiplexer being logically ANDED with a toggle-in signal to provide a toggle-out signal for a further counter stage in cascade.

Abstract: A clock recovery arrangement particularly suitable for recovering a clock signal from Manchester-encoded data. The system includes a locally generated clock at twice the data rate. This locally generated clock is phase locked to the incoming data transitions. Then, the locked locally generated clock is divided by two to produce a clock signal corresponding to the data rate. A clock flipper circuit operating according to a predetermined algorithm determines whether to change the polarity of the clock signal to provide a correct polarity recovered clock.

Abstract: Relatively distorted bits are restored by sampling the bits for a plurality of times during each bit interval. A count of a first binary level of the samples is made for less than the bit interval, so as to eliminate samples at the transitions of the bits. If the count reaches a selected number, a regenerated bit of the first binary level is produced, and if the count does not reach the selected number, a regenerated bit of a second binary level is produced.

Abstract: A system for radar remote sensing of near surface ocean currents in coastal regions. The system employs a pair of low power, transportable high frequency radar units to scatter signals from the shore off to the ocean waves. Underlying surface currents impart a slight change in velocity to the ocean waves which is detected by the radar units. Each radar unit can determine the angular direction of arrival of the radar echo signals by comparing the phase of the signals received at three short antennas on the shore. Signals scattered from the same point on the ocean by each of the two geographically separated radar units are used to construct a complete current vector for that point. The radar pair takes simultaneous measurements over an ocean area with a predetermined grid pattern. Vectors are constructed for each square section of the grid, and a map of the near surface current field is output in real-time by an on-site minicomputer.