Abstract: A spacecraft emulation system that can emulate both the attitude control subsystem and the non-attitude control subsystem is integrated into a single compact unit. The unit includes an emulated spacecraft control processor for processing attitude control information and an emulated central command and telemetry unit for interfacing simulated spacecraft data. The inlet also includes a first simulation engine that is operative to simulate the spacecraft attitude control system and a second simulation engine that is operative to simulate the spacecraft power, thermal, propulsion and payload subsystems. Both the first and second simulation engines are connected to the emulated spacecraft control processor via a respective bus. A host computer provides the command data and receives the telemetry data from the emulated spacecraft control processor.

Abstract: An adaptive quadrature amplitude modulation (“QAM”) decoding system for use in, for example, high speed, bandwidth efficient QAM communication systems includes a circuit that adaptively adjusts gain and voltage bias and provides adaptive equalization feedback based on the same signal used to decode the QAM symbols.

Abstract: A micro-gyroscope having electronic alignment by performing an electronic coordinate transformation on control voltages (VTX, VTy) through an attenuator network thereby canceling first and second harmonic signals from the output (Vthx, Vthy). The micro-gyroscope is tuned by automatic electronic compensation based on quadrature error that is applied to correct for variations in the gyroscope.

Abstract: A Fast Fourier Transform based digital radiometer providing a frequency contiguous set of noise temperature measurements to characterize an atmospheric vertical temperature profile. The radiometer also has Doppler correction to account for velocity of a vehicle on which the radiometer is located and direction changes of a scene being measured.

Abstract: A low voltage optical phase modulator includes a splitter having an input, a first output, and a second output. The input receives an optical signal and is split between the first and second outputs. A phase adjustment element is coupled to the second output and produces a predetermined optical shift in the optical signal to produce a phase-shifted optical signal. A first electroabsorptive element is coupled to the first output and blocks transmission of the optical signal when the first electroabsorptive element is activated with a low voltage. A second electroabsorptive element is coupled to the phase adjustment element and blocks transmission of the phase-shifted optical signal when the second electroabsorptive element is activated using the low voltage. An optical combiner having a first combiner input, a second combiner input, and a combiner output is coupled to the first and second electroabsorptive elements and receives the optical signal and the phase-shifted optical signal.

Abstract: A method (100) for identifying re-routing path solutions for signals within a switch network (10). The path solutions are subject to special constraints that provide the most desired solution for a user. The method applies an algorithm that works by transforming a global problem (110) into many individual sub-problems (112). The algorithm then solves the individual sub-problems (112) systematically according to desired constraints until the global solution is met (120). The method finds a unique state for each switch such that the overall requirements of the system are met.

Abstract: A multiple mode feed horn is provided for transmitting and receiving signals. The feed horn includes a transverse electric throat section, a transverse electric profile section, and a transverse electric aperture section. The transverse electric profile section propagates a first transverse electric (TE) mode. The transverse electric aperture section propagates a second TE mode. The multiple mode feed horn prevents propagation of traverse magnetic modes from said throat section to said aperture section.

Abstract: Spacecraft maneuvers (e.g., orbit transferring, stationkeeping and attitude controlling) of a first spacecraft are realized with conventional force and torque generators (e.g., thrusters and momentum wheels). Spacecraft maneuvers of a second spacecraft are realized through magnetic interaction between the first and second spacecraft using a closed loop control system. In particular, a magnetic moment vector m1 of a magnetic system of the first spacecraft and a magnetic moment vector m2 of a magnetic system of the second spacecraft are adjusted to apply selected force vectors and torque vectors to the first and second spacecraft using a closed loop control system.

Abstract: A fault tolerant integrated circuit employs triple redundant storage of data and continuous voting to protect the data from Single Event Upset, or SEU. The integrated circuit includes three or more registers and a majority voter. The three registers are connected in series to each other with the output of the first register being connected to the input of the second register and the output of the second register being connected to the input of the third register. The majority voter is connected to the output of each register and generates a signal corresponding to the majority of all of the register outputs. The output of the majority voter is connected to the input of the first register, thereby correcting any incorrect data stored in the registers.

Abstract: A linearized folding amplifier circuit (30) includes a comparator (40) that has a first state and a second state, and a switched output circuit that has a pair of outputs. The non-linearity in the response of a differential transistor pair to an input signal is partially linearized by a first resistor connecting the emitters of the two input transistors. The input is further linearized in response to the first and second state-controlling pairs of transistors and a differential error voltage therebetween that is replicated from the differential error in the base-voltages emitter voltages of the input differential pair. The output of the circuit is the combination of the partially linearized portion from the first resistor and a linearized transconductor circuit that has an output formed in response to the differential error.

Abstract: A satellite assembly 10 is provided, including an RF radiating element 12 including a plurality of RF choke elements 18, each of said plurality of RF choke elements 18 being defined by an RF dimensional set 20 including an RF depth 22 and an RF width 24. The satellite assembly 10 further includes a null aperture field zone 26 created by the plurality of RF choke elements 18, the null aperture field zone 26 created by tuning each of the RF dimensional sets 20. At least one field sensitive component 14 is positioned within said null aperture field zone 26.

Abstract: A high power optical combiner (18) is provided for amplifying an optical signal. The combiner (18) includes a splitter (20) having a splitter input (22)and two splitter outputs (24, 26). The splitter input (22) receives an optical signal which the splitter divides (20) into two sub-signals. The splitter outputs (24, 26) have respectively coupled thereto a reference arm (30) and a dither arm (32). Both arms (30, 32) receive the sub-signals from the respective splitter outputs (24, 26) and transmit the sub-signals in parallel. Each arm (30, 32) has an amplifier (34) integrated therein for amplifying the sub-signals in parallel thereby producing amplified sub-signals. The high power optical combiner (18) further includes a combining coupler (42) connected to both arms (30, 32). The combining coupler (42) has two coupler inputs (46, 48), and a coupler output (50). The coupler inputs (46, 48) receive the amplified sub-signals from the arms (30, 32).

Abstract: A satellite system includes a solar wing moveably connected to a satellite central body. A sensor, also coupled to the satellite central body, detects the movement of the body and generates a rate signal based on that movement. Additionally, an actuator, which controls momentum, is coupled to the satellite central body with maximum torque along the thermal shock axis. Subsequently, a rate-dominated thermal shock suppression controller, which is coupled to the satellite central body, receives the rate signal from the sensor to control the actuator.

Abstract: A compensation circuit and method for compensating for the threshold shift in an irradiated MOSFET. The method determines the gate threshold voltage to body voltage relationship to vary the body voltage with radiation. The compensation circuit (10) has at least one MOSFET (Q2) having the same channel type as the MOSFET being compensated (Q1). The at least one matching MOSFET (Q2) is connected to the gate of the MOSFET (Q1) being compensated. At least one MOSFET (Q3, Q4) having a channel type that is different from the channel type of the MOSFET (Q1) being compensated is connected to the gate of the matching MOSFET (Q2). The result is that the compensation circuit (10) controls a negative shift in the body voltage of the MOSFET (Q1) being compensated resulting in a higher threshold voltage.

Abstract: A bipolar device hardened against single event upset includes a voltage source, a substrate, and a surface contact. The substrate includes a first collector region, a first base region and a first emitter region. The first collector region has a first collector voltage and a first voltage threshold. The first voltage threshold is the voltage at which a bipolar device connected to the first collector or first emitter becomes upset. When the first collector voltage drops below the first voltage threshold, the attached bipolar device becomes upset. The first base region is adjacent to the first collector region and the first emitter region is adjacent to the first base region. The surface contact is disposed on the substrate and is coupled to a voltage bias generated by the voltage source. The voltage bias is greater then the first voltage threshold so that the first collector voltage is prevented from dropping below the first voltage threshold due to energetic particle induced charge.

Abstract: A chip-on-board electronic device includes an electronic device die affixed to a printed circuit board, and electrically interconnected thereto by wirebonds. The electronic device is protected by coating it with a layer of silicon oxynitride and, optionally, an overlying thin layer of a conformal coating such as parylene. Under some circumstances, a protective layer of an organic material may be used instead of the layer of silicon oxynitride. The chip-on-board electronic device may be protected with an overlying layer of the conformal coating.

Abstract: A synthesized reflector surface (12) for directing communication signals (27) in a communication system (10) that operates in a plurality of orbital slots and to a plurality of regions (28) within a first coverage area (30) is provided. The synthesized reflector surface (12) includes a plurality of contiguous profile surfaces (40) that form the reflector surface (12). Each of the plurality of contiguous profile surfaces (40) alters the phase-of the communication signals (27) to provide a first gain for a first satellite orbit location (32) and a second gain for a second satellite orbit location (34). The plurality of contiguous profile surfaces (40) directs the signals from the location (32) in a first orientation to the first coverage area (30) or from the location (34) in a second orientation to the first coverage area (30). A method is provided for synthesizing the reflector surface (12).

Abstract: A circuit assembly has a heat sink assembly and a chip scale package assembly. The chip scale package assembly has an integrated circuit die coupled to a first printed wiring board. The heat sink assembly has an integrated circuit die coupled to a second printed wiring board. Preferably, the heat sink assembly and the chip scale package assembly are assembled separately then assembled together. The circuit pads on the first printed wiring board correspond with circuit pads on the second printed wiring board. The circuit pads may be coupled together by solder or adhesive bonding. The circuit pads on the first printed wiring board may have solder balls formed of high temperature solder that do not melt when the heat sink assembly is assembled with chip scale package assembly. The solder balls allow chip scale package assembly to maintain a predetermined distance from the circuit pads on the second printed wiring board.

Abstract: A system for testing an embedded processor, such as an embedded processor for a spacecraft. The system comprises an Emulated Spacecraft Control Processor (ESCP) which contains the embedded processor, a simulation engine, and a host computer. The emulated spacecraft control processor includes a dual-port memory for emulating the memory for the embedded processor and data transfer logic which monitors cycles of the embedded processor to arbitrate access to the dual-port memory, the data transfer logic is operative to allow an access to the dual-port memory when the embedded processor performs an I/O cycle, wherein the access is performed before a subsequent machine cycle of the embedded processor.

Abstract: A notch filter circuit is provided including a first stage circuit and a second stage circuit. The first stage circuit sums a filter input signal with a filter output signal to form a summation signal. The second stage circuit includes a first tee network and a second tee network. The first tee network low-pass filters the filter input signal to form a first tee output signal. The second tee network high-pass filters the summation signal to form a second tee output signal. A first multiplying digital-to-analog converter is electrically coupled to the first tee network and the second tee network. The first converter modifies the gain of the second tee network in response to a gain signal to form a corrected second tee network signal, thereby adjusting a notch filter frequency.