Abstract: Electromagnetic (EM) feeds can illuminate a standard primary reflective antenna with a plurality of feed beams each having a different orbital angular momentum (OAM) or polarization. The reflective antenna, which can be a non-OAM antenna, can reflect the feed beams and thereby produce a composite OAM transmission comprising each of the feed beams. A non-OAM primary antenna can thus transmit a plurality of OAM feed beams as a composite OAM transmission.

Abstract: Adaptive filtering is used to substantially cancel distortion in radio frequency (RF) signals. Such adaptive filtering can be used in an RF transmitting module to pre-compensate an RF signal with compensation (inverse) distortion to cancel inherent transmission path distortion from the RF signal. Adaptive filtering can also be used in a multi-carrier RF receiving module to cancel from a given carrier signal distortion due to cross talk from adjacent carrier signals. Adaptive filtering in an RF transceiver can be used to cancel from a received RF signal distortion arising from leakage of a transmit signal into the receive path.

Abstract: A data alignment method is provided by iteratively increasing the delay of each data input line of a system component until a test signal transmitted on each data input line is received at the system component at substantially a predetermined time.

Abstract: A circuit card can include a circulator for routing a signal from a first amplifier to an antenna and for routing a signal from the antenna to a second amplifier, replacing a traditional transfer switch. The circulator can be a surface mount element to enable the circulator, first amplifier, and second amplifier to be mounted on the same circuit card thereby minimizing the size of a transceiver that employs the circuit card. Multiple circulators can be included on the same circuit card to allow for multi-band operation.

Abstract: A horn-reflector antenna for tracking the location of in-flight aircraft is provided. The antenna includes an upwardly-opening horn having a reflector attached thereto. The horn may have an asymmetric rectangular cross-section and comprise at least one upwardly and outwardly extending side wall. The reflector includes a reflecting surface that may have a generally hyperbolic paraboloid shape or saddle shape. The horn and reflector may be constructed from a polymer material in an injection molding process. The reflecting surface of the reflector and the inner surfaces of the horn may be coated with a reflective or conductive material, for example, a paint comprising sliver-plated copper particles. In use, the horn-reflector antenna may be adapted to rotate around the longitudinal axis of a stationary waveguide feed. As such, the antenna of the present invention can be adapted for operation without the use of a rotary joint or a slip ring.

Abstract: The angular position of an output gear can be determined from the phase difference between the angular positions of pinions engaged with the output gear. The first pinion can have a K-number of teeth, the second pinion can have an L-number of teeth, and the output gear can have an M-number of teeth. The relationship between K, L, and M can include the following: M is the least common multiple of K and L; and the absolute value of the difference between M divided by K and M divided by L is one. It can also be said that the absolute value of L subtracted from K is a non-zero integer.

Abstract: An electronic assembly can include a support structure, a circuit substrate coupled to a first portion of the support structure, and a composite material panel coupled to a second portion of the support structure. An electronic device can be coupled to a mounting surface of the circuit substrate and disposed within a space enclosed by walls of the support structure. The panel can include contiguous sections inner surfaces of which can be oriented within twenty-five degrees of parallel to said mounting surface. Each section can be significantly more thermally conductive generally parallel to the inner surface of the section than generally perpendicular to the inner surface.

Abstract: A digital communications receiver can comprise a digital filter that can be configured and later reconfigured multiple times as, for example, a matched filter, an equalizer, a matched filter and equalizer, or the like. For example, the digital filter can be initially configured as a matched filter for use with a correlation module to detect pilot symbols. Detected pilot symbols can be utilized to estimate characteristics of a channel from the distant transmitter to the receiver, and the estimated channel characteristics can be used to determine coefficients for an equalizer for reducing channel distortion in future transmissions received over the channel. The digital filter can then be configured as an equalizer or a matched filter and equalizer. If the later, the digital filter can both equalize incoming transmissions from the distant transmitter and, with a correlation module, identify any pilot symbols in the transmissions.

Abstract: Detecting timing of a synchronization sequence included in a data stream transmitted in a noisy channel. The synchronization sequence is a known data sequence purposely injected into the data stream for synchronization. A data stream waveform, is obtained from a noisy communication channel. The data stream waveform includes an instance of a synchronization sequence waveform. One or more samples of the synchronization sequence waveform are obtained. One or more samples of a model synchronization sequence waveform are obtained. The model synchronization sequence waveform models an expected waveform for the synchronization sequence being transmitted on the communication channel by applying the synchronization sequence to a model of the communication channel.

Abstract: The estimated gain profile of an amplifier can be modified during operation of the amplifier utilizing detected values of the amplification level of signals produced by the amplifier. The amplification levels can be detected at a location that is remote from the amplifier. New expected amplification levels can be determined for corresponding control signal values in the estimated gain profile. Digital filtering such as Kalman filtering can be used to determine the new expected amplification levels. The estimated gain profile can be modified with the new expected amplification levels.

Abstract: The security level of a communications terminal can be changed during operation. A key loading device can reconstitute a key encryption key from plural split portions. The split portions can be loaded into the key loading device via various interfaces. The reconstituted key encryption key can be used to unwrap wrapped keys stored in the key loading device.

Abstract: A system in which a sending node sends modulated waveform signals to a receiving mode can include the capability to change the waveform type of the modulated waveforms from a current waveform type to a new waveform type. The sending node can generate and send to the receiving node a variable length header that provides the receiving node sufficient information for the receiving node to demodulate modulated waveform signals modulated in accordance with the new waveform type. The variable length header can identify the parameters in a parameter set defining the new waveform type that have different values as compared to the current waveform type.

Abstract: Processes for determining imperfection offsets between an antenna and the platform to which the antenna is coupled, where the imperfection offsets are unknown offsets due to imperfections such as manufacturing imperfections. The platform can include an orientation mechanism that provides the orientation of the platform, and the imperfection offsets can be between the antenna and the orientation mechanism. The processes can include determining two different relative pointing vectors that correspond to a detected peak strength of a test signal transmitted between one or more targets and the antenna. The processes can further include utilizing an optimization process to determine the heading, pitch, and roll of the imperfection offsets from the two different relative pointing vectors.

Abstract: The present invention is generally directed to using code division multiplexing (CDM) on the beacon and traffic channels while lowering the power of the beacon channel so that it rides under the traffic channel and becomes very difficult to detect. In this way, the beacon channel can contain sensitive information for decoding the traffic channel while remaining hidden from unintended recipients. By hiding the beacon channel, the CDM technique can be particularly beneficial in adaptive waveform systems where sensitive traffic channel acquisition information is regularly transmitted to the receiver.

Abstract: A signal coupler can couple a processed version of an outgoing signal from a transmission path to a receive path in a transceiver. A connector can provide the processed version of the outgoing signal to a pre-distortion module, which can generate a pre-distortion signal to pre-compensate outgoing signals in the transmission path of the transceiver. A receive path of a transceiver can thus be utilized as a feedback path to a pre-distortion module.

Abstract: A phase shifting component of a waveguide comparator subsystem can effect a relative phase shift that advances an input signal A relative to an input signal B. A comparator component can then split those signals such that a first part of signal A and a second part of signal B are combined at a difference port, and a first part of signal B and a second part of signal A are combined at a sum port. The comparator can delay the phase of the second parts of the signals such that, with the relative phase shift of the phase shifting component, the first part of signal A and the second part of signal B are one-hundred eighty degrees (180°) out of phase at the difference port, and the second part of signal A and the first part of signal B are in phase at the sum port.

Abstract: Night vision devices utilize image intensifier tubes to see in low light conditions. A man-portable tester allows an operator to check for defects and determine the image resolution of the image intensifier tube quickly and easily without a power source or a darkened room.

Abstract: A decoder for decoding received vectors r encoded in accordance with a forward error correction code having a parity check matrix H with multiple regions at least two of which have patterns of ones with different pattern characteristics. The decoder can include a permuted decode module configured to decode in accordance with a permuted version of the parity check matrix H in which the ones in one of the regions are permuted into a permuted pattern that has a pattern characteristic of the other region. The decoder can also include a reorder module that permutes probabilities of a received vector r to be decoded to correspond with the permuted parity check matrix H.

Abstract: A multi-mode parameter adaptation module can comprise different modes for generating parameters to minimize an error between an output of an adaptive processor and an ideal output of the adaptive processor. A mode control module can monitor a performance signal p indicative of an operating condition a receiver of which the adaptive processor is a part. Upon detecting a change condition form the performance signal p, the mode control module can change the operating mode of the parameter adaptation module to suit the current operating condition.

Abstract: A transmit antenna or antennas can be configured to transmit a composite orbital angular momentum (OAM) radio frequency (RF) beam comprising a plurality of individual OAM RF signals each having a different OAM mode. An array of antennas for receiving and resolving the composite OAM beam into the individual OAM signals can be located entirely within a relatively small sector of a far field pattern of the composite OAM beam. A processing module connected to the antennas of the receive array can resolve the composite OAM beam into its individual OAM signals using angular resolution. The transmit antenna can transmit the individual OAM signals—and thus the composite OAM beam—as full OAM signals or partial-beam OAM signals.