Abstract: An ultrasonic generator is provided. The ultrasonic generator includes an amplifier for outputting a drive signal to an ultrasonic atomizing nozzle, and a microcontroller, coupled to the amplifier, to control an output power of the amplifier. The microcontroller includes a load leveling operating mode in which the output power of the amplifier fluctuates to match changing load conditions of the ultrasonic atomizing nozzle.

Abstract: An ultrasonic nozzle configured to form relatively small drops of liquid at relatively high rates. The nozzle includes two horns, at least one of which includes a ceramic material. The nozzle also includes one or more transducers that cause mechanical motion in at least one of the horns. In addition, a method of forming micrometer-scaled drops of liquid at relatively high rates is provided.

Abstract: A technique for enhancing the signal-to-noise performance of a digital communication link without affecting its power flux density. An information data stream has its original signaling rate selectively reduced prior to transmission, to enhance signal-to-noise performance. Then the reduced signaling rate information signal is combined with a pseudorandom data sequence at the original signaling rate, to provide a randomized data sequence to be transmitted at the original signaling rate, thereby maintaining power flux density levels below those permitted by regulatory limits.

Abstract: A technique for reducing power requirements in a communication transponder by converting signals in multiple uplink channels carried in frequency division multiplexed (FDM) form on multiple uplink beams, to a lesser number of downlink beams that operate in time division multiplexing (TDM) but at a bandwidth different from and preferably greater than the bandwidth of the uplink channels. Because the TDM downlinks can utilize amplifiers operating at or near peak power, whereas conventional FDM downlinks must operate with amplifiers backed off to minimize intermodulation products, use of the TDM downlinks effects significant power savings.

Abstract: A power gated variable hop cycle beam laydown (700) manifests itself as first cells (C, D) supported by a first hop cycle, second cells (G, H) supported by a second hop cycle, and transition cells (E, F) supported by a transition hop cycle. The transition hop cycle uses power gating to transition the laydown (700) from cells (C, D) operating at the first hop cycle to cells (G, H) operating at the second hop cycle. To this end, the transition hop cycle power gates its downlink beam for a portion of time needed to reduce interference between nearby (e.g., adjacent) cells.

Abstract: A method for ultra wideband (UWB) communication in which UWB pulses encode binary data as either normal or inverted (anti-podal) pulses. In the case of pulses of a carrier signal, each pulse has the carrier signal either inverted or in phase, that is, shifted by 180°, or not. For example, a binary “1” may be encoded as a normal or non-inverted pulse and a binary “0” as an inverted pulse. After each carrier pulse is rectified and filtered, detection is effected using a threshold value of zero, resulting in increased immunity to noise, compared with detection of unidirectional pulses. In one aspect of the invention, data pertaining to multiple communication channels are encoded in time-divided portions of each UWB pulse.

Abstract: The present invention relates to an apparatus and process for producing a thin organic film on a substrate using an ultrasonic nozzle to produce a cloud of micro-droplets in a vacuum chamber. The micro-droplets move turbulently within the vacuum chamber, isotropically impacting and adhering to the surface of the substrate. The resulting product has a smooth, continuous, conformal, and uniform organic thin film, when the critical process parameters of micro-droplet size, shot size, vacuum chamber pressure, and timing are well-controlled, and defects such as “orange peel” effect and webbing are avoided. The apparatus includes an improved ultrasonic nozzle assembly that comprises vacuum sealing and a separate, independent passageway for introducing a directed purging gas.

Abstract: An improved decoding technique useful for hard decision decoding, such as quadrature phase shift keying (PSK) and quadrature amplitude modulation (QAM), as well as soft-decision techniques, such as Viterbi decoding and trellis decoding. The system in accordance with the present invention provides adaptive decision regions for hard-decision decoding techniques and adaptive metrics for soft-decision detection techniques in which the decision boundaries and reference constellations, respectively are optimized in order to minimize the bit error rate (BER). In particular, the decision boundaries and metrics are optimized based on the locations of the received constellation points.

Abstract: A method and apparatus are provided for supporting the transmission of communications data in a satellite communications network 10 between user terminals 15–18 and a ground station 14 via a satellite 12. At least one carrier signal is generated in a beam spot and conveys communications data over at least one downlink 22–25 to the user terminals 15–18. The carrier signal is modulated simultaneously with independent communications data streams EDP15 and EDP 18 over modulation channels 802 and 804, respectively, of a multi-dimensional modulator 400. By passing independent data streams over each dimension of an n-dimension modulation technique, different encoding schemes may be assigned to user terminals 15–18 based upon the strength of the signal received by the user terminal 15–18.

Abstract: A data routing subsystem (200) for a communication satellite includes an inbound module (602) that accepts demodulated uplink data. The inbound module (602) includes a routing table (702) that stores queue tags (714) specifying downlink beam hop locations (302, 304) for the uplink data. The subsystem (200) also includes a self addressed packet switch (608) having an input port coupled to the inbound module (602), and an outbound module (610) coupled to an output port of the switch (608). A memory (804) in the outbound module (610) stores the uplink data in accordance with the downlink beam hop locations (302, 304). A multiple beam array antenna (116–122) is coupled to the outbound module (610). The multiple beam array antenna (116-122) includes a first feed element (116) assigned to a first downlink beam hop location (302) and a second feed element (118) assigned to a second downlink beam hop location (304).

Abstract: A method of packet concatenation in TDMA transmission is provided. The method includes the step of transmitting from a terminal in a first time slot (202), including overhead information (108-112) and symbols representing terminal data (114). The method also includes the step of transmitting from a terminal (possibly the same terminal) in a subsequent time slot (204-208), including a subset of the overhead information (108-112) and symbols representing terminal data (114). The subsequent time slot may be a consecutive time slot. The overhead information may include, for example, guard time (110), ramp time beam settling time (108) and a preamble (112).

Abstract: Methods and devices for predistorted 12/4 Quadrature Amplitude Modulation that compensate for distortion from a nonlinear element. Modulator input bits are mapped (40) to a plurality of nonreturn-to-zero (NRZ) modulator control bit (20-30). The mapping is determined by desired points on a 12/4 QAM constellation. At least one phase shift device (4, 6) receives an input signal and at least one of the plurality of modulator control bit. At least two quaternary phase shift keying (QPSK) devices (8, 10) receive phase shifted signals from at least one phase shift device. Each of at least two QPSK devices receives at least one of the plurality of NRZ symbols. An attenuator (32) that attenuates a first QPSK signal outputted from a first QPSK device of the at least two QPSK devices. A summer (34) sums the attenuated first QPSK signal with a second QPSK signal. The second QPSK signal is outputted from a second QPSK device of the two QPSK devices. The summer outputs a predistorted 12/4-QAM signal.

Abstract: A communication subsystem (300) for transmitting error correction coded data in packets (200) includes an input buffer (302) storing unencoded data, a product coder (304) coupled to the input buffer, and a time division transmitter (306). The product coder (304) outputs product coded data packets (200) having a packet size, and the time division transmitter (306) transmits the product coded data packets (200) in a data section (109) of a frame (104). The data section (109) has a length substantially equal to an integer multiple of the packet size. The communication subsystem (300) may use a (s, t)×(n, m) product code specifically adapted to product code 53 byte ATM cells. A method for communicating error correction coded data in packets includes storing unencoded data in an input buffer (402), product coding the unencoded data (404), and outputting product coded data packets (406) having a packet size.

Abstract: A method and apparatus are provided coding communications signals 16 carried between transmitting and receiving stations 12 and 14. A data stream from a communications signal is encoded with an outer code 22 to form an outer-coded data stream that is passed to an inner coder 26. The inner coder 26 applies an inner code and punctures the resulting coded data stream by deleting at least one bit from each symbol to achieve a desired data rate and coding level. The system 10 offers multiple levels of puncturing to vary the coding level between heavy and light. The inner code may be a Nordstrom-Robinson code and the outer code may be a Reed-Solomon code.

Abstract: A ground terminal renders feasible a communications system that locates two satellites at the same node along the geostationary arc. Each satellite is capable of receiving RF signals through an uplink channel and transmitting RF signals through a downlink channel distinct from the uplink channels. The ground terminal is able to transmit RF signals to only one of the satellites, but can receive RF signals from both of the satellites. The ground terminal includes an antenna, an RF signal processor that includes two demodulators for processing signals from the two downlink channels, and a data processor.

Abstract: A communications system includes two satellites located at the same node along the geostationary arc each capable of receiving RF signals through an uplink channel and transmitting RF signals through a downlink channel distinct from the uplink channels. At least two user terminals are in the system, with each user terminal able to transmit RF signals to only one of the satellites, but at least one of the user terminals is able to receive RF signals from both of the satellites.

Abstract: The present invention relates to an apparatus and process for producing a thin organic film on a substrate using an ultrasonic nozzle to produce a cloud of micro-droplets in a vacuum chamber. The micro-droplets move turbulently within the vacuum chamber, isotropically impacting and adhering to the surface of the substrate. The resulting product has a smooth, continuous, conformal, and uniform organic thin film, when the critical process parameters of micro-droplet size, shot size, vacuum chamber pressure, and timing are well-controlled, and defects such as “orange peel” effect and webbing are avoided. The apparatus includes an improved ultrasonic nozzle assembly that comprises vacuum sealing and a separate, independent passageway for introducing a directed purging gas.

Abstract: A decoder of a data signal subjected to phase shifting keying (PSK) modulation uses an inner decoder for short block codes within a phase locked loop which is adapted to process the data signal with multiple initial phase/frequency error estimates and to output sets of codewords and phase/frequency error estimates respectively corresponding to the initial phase/frequency estimates. A selection circuit (720) selects and forwards the output corresponding to one of the multiple phase/frequency estimates. An outer Reed-Solomon block decoder (319) corrects errors in the codewords from the set of associated codewords selected by the selection circuit.

Abstract: A decoder of a data signal subjected to phase shifting keying (PSK) modulation uses an inner decoder for short block codes within a phase locked loop which is adapted to process the data signal with multiple initial phase/frequency error estimates and to output sets of codewords and phase/frequency error estimates respectively corresponding to the initial phase/frequency estimates. A selection circuit (720) selects and forwards the output corresponding to one of the multiple phase/frequency estimates. An outer Reed-Solomon block decoder corrects errors in the codewords from the set of associated codewords selected by the selection circuit. The Reed-Solomon block decoder corrects a combination of random errors and erasure errors where the erasure errors are chosen based on reliability metrics generated by the inner code or else the first positions of the data bursts are chosen for erasures as these are most likely to be in error relative to other positions.

Abstract: A method and apparatus are provided for supporting the transmission of communications data in a satellite communications network 10 between user terminals 15-18 and a ground station 14 via a satellite 12. At least one carrier signal is generated in a beam spot and conveys communications data over at least one downlink 22-25 to the user terminals 15-18. The carrier signal is modulated simultaneously with independent communications data streams EDP15 and EDP 18 over modulation channels 802 and 804, respectively, of a multi-dimensional modulator 400. By passing independent data streams over each dimension of an n-dimension modulation technique, different encoding schemes may be assigned to user terminals 15-18 based upon the strength of the signal received by the user terminal 15-18.