Abstract: An electronic apparatus that includes a digital processor (12), a first digital pulse width modulator (304), a second digital pulse width modulator (306), a combining circuit (308), and a load (310). The digital processor (12) produces a first digital signal (314) and a second digital signal (316). The first digital pulse width modulator (304) is responsive to the first digital signal (314), and the second digital pulse width modulator (306) is responsive to the second digital signal (316). The combining circuit (308) is responsive to the first digital pulse width modulator (304) and the second digital pulse width modulator (306). The load (310) is responsive to the combining circuit (308).

Abstract: A structure (24) includes a plurality of repeaters (34), each having a primary transceiver (36) and a secondary transceiver (38) electromagnetically located upon a clear side (30) and a blocked side (32), respectively, of a barrier (26). Each primary transceiver (36) and secondary transceiver (38) communicate using an intra-repeater signal (46). Each intra-repeater signal (46) is output from its respective primary transceiver (36), combined with other intra-repeater signals (46) by a combiner (50), passed over a communication infrastructure (22), separated from other intra-repeater signals (46) by a separator (54), and input to its respective secondary transceiver (38). Optionally, each intra-repeater signal (46) may be retrieved from the communication infrastructure (22), separated from other intra-repeater signals (46) by a separator (62), amplified by a bandpass amplifier (64), combined with other intra-repeater signals (46) by a combiner (66), and inserted back into the communication infrastructure (22).

Abstract: A method and apparatus for efficiently amplifying input signals includes multiple amplifiers (20, 30). Each amplifier receives a signal from a power divider (12) where the input signal is split with substantially equal phase. Each amplifier drives a load (40) through a parallel coupled line pair (26, 36). The parallel coupled line pairs are preferably implemented in micro-strip or strip line technology. Each amplifier includes gate bias inputs (24, 34) and drain bias inputs (22, 32). The gate bias inputs can be biased equally and the drain bias inputs can be biased equally, resulting in a parallel, power combined, amplifier configuration. Alternately, the drain bias inputs can be staggered, or the gate bias inputs can be staggered to increase efficiency.

Abstract: A phased array antenna (1000) is formed using a number of independently controllable piezoelectric phase shifters (1300) which results in a low cost phased array antenna that is functional at microwave and/or millimeter wave frequencies. In addition, the independently controllable piezoelectric phase shifters (1300) have sufficient phase range to allow a single antenna to be steered over a wide angle field of view. Piezoelectric phase shifters (1300) comprise at least one-voltage variable capacitor (1310, 1320, FIG. 2). Typically, the piezoelectric material used in the voltage variable capacitors is selected from a group consisting of lead-titanate (PbTiO.sub.3), lead-zirconate (PbZrO.sub.3), barium-titanate (BaTiO.sub.3), and lead-zirconate-titanate (PbZr.sub.x Ti.sub.1-x O.sub.3), where x varies from zero to one.

Abstract: Private Global Networks (PGNs) between communication terminals (110, 114, 116, 118) are established within a satellite communication system (100). Each PGN provides to its users a network of dedicated communication paths which have durations that exceed the duration of a particular call. A dedicated communication path is established by determining (416, 424) hand-off schedules for satellite-to-terminal links for both a source and destination terminal, and also by determining (428) satellite cross-link schedules necessary to maintain the dedicated path for a duration which exceeds the duration of a particular call.

Abstract: A harmonic generator (20) converts an input signal (24) at a fundamental frequency (28) into an output signal (32) at a harmonic frequency (34). A non-linear device (22) converts the input signal (24) into an intermediate signal (38) in which the harmonic frequency (34) has a maximized amplitude (40) determined by a conduction angle (26). A harmonic filter (68) produces a filtered signal (70) proportional to the amplitude (40) of the harmonic frequency (34) within the intermediate signal (38). A detector (80) produces a control signal (82) proportional to the amplitude of the filtered signal (70). A control circuit (84) produces a variable bias signal (50) for non-linear device (22), bias signal (50) being proportional to the amplitude of the control signal (82) and determining the conduction angle (26). An output filter (88) converts the intermediate signal (38) into an output signal (32) at the harmonic frequency (34).

Abstract: A high speed, low power 3-2 adder (300, 500) with latchable outputs comprises a most significant bit (MSB) adder circuit (100) and a least significant bit (LSB) adder circuit (200). MSB adder circuit (100) includes three differential data inputs (A1, B1, and C1), a latch enable input (LE1), three separate bias points, and an MSB output. In addition the LSB adder circuit includes three differential data inputs (A2, B2, and C2), a latch enable input (LE2), three separate bias points and a LSB output. Internal latch circuits (172, 272) and latch enable circuits (174, 274) are provided in each adder stage. Internal latch enable inputs are connected in parallel in one configuration. Separate latch enable inputs are provide in a second configuration. Separate bias points are also provided in each adder stage.

Abstract: Additional resources and services are provided in a satellite communication system (100) through the use of seam satellites (52). One or more seam satellites (52) are coupled to communication satellites (12) in an existing constellation using previously unused crosslinks. The seam satellites (52) are located between orbital planes (31 and 36) in which the communication satellites (12) are moving in opposite directions with respect to each other. Seam satellites (52) can provide new services such as earth sensing and observation. Seam satellites (52) can also provide attachment points for other new space-based users. Some of the communication units (26) can communicate with the seam satellites (52) via communication satellites (12). This allows these communication units (26) to use the new services provided by the seam satellite (52). Seam satellites (52) can be controlled by separate control centers or can be controlled by the control center for the communication satellites (12).

Abstract: A multiple-user subscriber unit (MCU) (110) is used by subscribers (240) in a group of subscribers to obtain communications services from the communication system. MCU (110) is co-located with a mobile vehicle and a group of subscribers. The MCU (110) and procedure (300) enable the MCU to reduce impulsive loading of the communication system caused by simultaneously requests for service. MCU (110) determines a set of tasks which includes a number of call-processing tasks, a number of hand-off tasks, and a number of re-registration tasks. Priorities are established for the tasks which must be performed. A schedule is established based on the priorities and the amount of time required to perform the tasks and the total amount of time available to perform the tasks. Tasks are performed according to the schedule and this reduces impulsive loading of the communication system (100).