Abstract: A vehicle communication system includes an optical cable, a centralized hub device, and an antenna hub device. The centralized hub device is connected to a first end of the optical cable and is configured to receive radio frequency (RF) signals from multiple end devices. The centralized hub device is configured to convert the RF signals to respective optical carrier signals and transmit the optical carrier signals along the optical cable at different, non-overlapping wavelength bands of a combined optical signal. The antenna hub device is connected to a second end of the optical cable. The antenna hub device is configured to receive the combined optical signal and to convert the optical carrier signals thereof to RF signals, amplify the RF signals, and transmit the RF signals to one or more antennas.

Abstract: A vehicle communication system includes an optical cable, a centralized hub device, and an antenna hub device. The centralized hub device is connected to a first end of the optical cable and is configured to receive radio frequency (RF) signals from multiple end devices. The centralized hub device is configured to convert the RF signals to respective optical carrier signals and transmit the optical carrier signals along the optical cable at different, non-overlapping wavelength bands of a combined optical signal. The antenna hub device is connected to a second end of the optical cable. The antenna hub device is configured to receive the combined optical signal and to convert the optical carrier signals thereof to RF signals, amplify the RF signals, and transmit the RF signals to one or more antennas.

Abstract: A method comprises collecting a data set of field characterization measurements at a location inside a reverberant cavity excited by signals having multiple discrete electromagnetic frequencies; and performing a number (n) of circular shifts on the data set by a frequency step (?f) and computing a covariance-based coefficient at each shift until the coefficient indicates a lack of correlation. The method further comprises computing a quality factor (Q) of the reverberant cavity as fc/(?f×n), where fc is center frequency of the data set.

Abstract: Example systems and methods for nondestructive ultrasonic testing are provided. One example system includes at least one air-coupled ultrasonic transducer configured to emit primary ultrasound waves that interfere with each other. The primary ultrasound waves include fundamental frequency components that are multiples of each other and emitted simultaneously in locked phase. Further, the interference of the primary ultrasound waves generates a plurality of frequency harmonics in the air. The system also includes at least one receiver configured to receive ultrasonic waves emitted from an object under test.

Abstract: A system is provided that includes a Doppler radar unit that transmits a first electromagnetic wave having a first frequency, which a test system converts to a first electrical signal having the first frequency. The test system generates a second electrical signal having a second frequency, and mixes the first and second electrical signals to produce a third electrical signal having a third, sum or difference frequency. The third frequency represents a Doppler-shifted frequency caused by reflection of the first electromagnetic wave by a target at a distance from the Doppler radar unit. The test system converts the third electrical signal to a second electromagnetic wave having the third frequency, and transmits the second electromagnetic wave back to the Doppler radar unit for calculation of a speed representing that of the target as a function of the first and third frequencies, from which the Doppler radar unit may be calculated/certified.

Abstract: Example systems and methods for nondestructive ultrasonic testing are provided. One example system includes at least one air-coupled ultrasonic transducer configured to emit primary ultrasound waves that interfere with each other. The primary ultrasound waves include fundamental frequency components that are multiples of each other and emitted simultaneously in locked phase. Further, the interference of the primary ultrasound waves generates a plurality of frequency harmonics in the air. The system also includes at least one receiver configured to receive ultrasonic waves emitted from an object under test.

Abstract: In one embodiment a method to evaluate a shielding effectiveness of an enclosed structure, comprising collecting synthetic aperture data from an electromagnetic transmission originating from within the enclosed structure to generate a synthetic aperture dataset, performing angular spectrum processing on the synthetic aperture dataset to generate an angle of arrival dataset and determining a shielding effectiveness parameter from the angle of arrival dataset. Other embodiments may be described.

Abstract: A method for determining a direct antenna coupling in a reverberant environment is disclosed. Radiowave energy is emitted in the reverberant environment from a transmitting antenna to a receiving antenna at a plurality of frequencies, and discrete frequency stirring data is collected at a plurality of frequencies. The discrete frequency stirring data is amplitude corrected and phase corrected using an expected amplitude shift and an expected phase shift at each of the frequencies to provide corrected discrete frequency stirring data. The direct antenna coupling is determined based on the corrected discrete frequency stirring data.

Abstract: A system is provided that includes a Doppler radar unit that transmits a first electromagnetic wave having a first frequency, which a test system converts to a first electrical signal having the first frequency. The test system generates a second electrical signal having a second frequency, and mixes the first and second electrical signals to produce a third electrical signal having a third, sum or difference frequency. The third frequency represents a Doppler-shifted frequency caused by reflection of the first electromagnetic wave by a target at a distance from the Doppler radar unit. The test system converts the third electrical signal to a second electromagnetic wave having the third frequency, and transmits the second electromagnetic wave back to the Doppler radar unit for calculation of a speed representing that of the target as a function of the first and third frequencies, from which the Doppler radar unit may be calculated/certified.

Abstract: A method comprises collecting a data set of field characterization measurements at a location inside a reverberant cavity excited by signals having multiple discrete electromagnetic frequencies; and performing a number (n) of circular shifts on the data set by a frequency step (?f) and computing a covariance-based coefficient at each shift until the coefficient indicates a lack of correlation. The method further comprises computing a quality factor (Q) of the reverberant cavity as fc/(?f×n), where fc is center frequency of the data set.

Abstract: Technologies are described herein for wirelessly measuring liquid quantity in an enclosure. According to various aspects, an incident electromagnetic wave is transmitted within a conductive enclosure. One or more rebound electromagnetic waves that correspond to the incident electromagnetic wave are received. Using the rebound electromagnetic waves, a transfer function of the rebound electromagnetic waves is measured and a quantity of liquid stored in the enclosure is calculated based on the measured transfer function.

Abstract: Nondestructive inspection of a plurality of aircraft hat stiffeners includes exciting cavities of the stiffeners with electromagnetic radiation, and analyzing electromagnetic field responses of the cavities to detect state changes of the stiffeners.

Abstract: Technologies are described herein for wirelessly measuring liquid quantity in an enclosure. According to various aspects, an incident electromagnetic wave is transmitted within a conductive enclosure. One or more rebound electromagnetic waves that correspond to the incident electromagnetic wave are received. Using the rebound electromagnetic waves, a transfer function of the rebound electromagnetic waves is measured and a quantity of liquid stored in the enclosure is calculated based on the measured transfer function.

Abstract: Systems and methods to stir an electromagnetic (EM) field of an EM reverberation chamber are disclosed. A particular system includes an EM reverberation chamber. The system also includes a transmit antenna and a receive antenna operable to generate an EM field within the EM reverberation chamber. The system further includes a variable charged particle source to stir the EM field by varying introduction of charged particles into the EM field.

Abstract: Systems and methods to stir an electromagnetic (EM) field of an EM reverberation chamber are disclosed. A particular system includes an EM reverberation chamber. The system also includes a transmit antenna and a receive antenna operable to generate an EM field within the EM reverberation chamber. The system further includes a variable charged particle source to stir the EM field by varying introduction of charged particles into the EM field.

Abstract: Nondestructive inspection of a plurality of aircraft hat stiffeners includes exciting cavities of the stiffeners with electromagnetic radiation, and analyzing electromagnetic field responses of the cavities to detect state changes of the stiffeners.

Abstract: The “discrete frequency stir” (DFS) method provides improved mode stir testing of electromagnetic characteristics of an enclosure/cavity. Adequate sampling of the electric field inside the enclosure/cavity is provided by electronic perturbation or “stirring” of the field with a short duration, continuous wave, radiated source where the wave frequency is stepped in small steps across a frequency range of interest. The frequency steps are selected to be at least slightly larger than the resonant mode bandwidth associated with the given enclosure/cavity in order to provide statistically independent measurements. A stirring bandwidth is selected to encompass a statistically significant number of these measurement samples while maintaining adequate frequency resolution. A statistical evaluation of the measured field is then performed over this stirring bandwidth.

Abstract: The “discrete frequency stir” (DFS) method provides improved mode stir testing of electromagnetic characteristics of an enclosure/cavity. Adequate sampling of the electric field inside the enclosure/cavity is provided by electronic perturbation or stirring of the field with a short duration, continuous wave, radiated source where the wave frequency is stepped in small steps across a frequency range of interest. The frequency steps are selected to be at least slightly larger than the resonant mode bandwidth associated with the given enclosure/cavity in order to provide statistically independent measurements. A stirring bandwidth is selected to encompass a statistically significant number of these measurement samples while maintaining adequate frequency resolution. A statistical evaluation of the measured field is then performed over this stirring bandwidth.

Abstract: A container filler assembly, as for berries, having a filler hopper located above a central filler conveyor driven at a slower speed than an upstream denesting and infeed conveyor which feeds empty containers to the filler conveyor, and an exit conveyor downstream of the filler conveyor driven at a greater speed than the filler conveyor, such that spaced containers on the denesting conveyor are put into abutment as they approach the filler hopper outlet, and subsequently placed again in a spaced condition after filling for dropping any berries caught on the container rims and for being closed as by placement of a wrapper on the filled container or closure of the clamshell container. The conveyors have overlapping driven V-belts with high friction surfaces.The denesting conveyor is preferably directly driven by a motor, while the filler conveyor and the exit conveyor are driven through a controlled clutch from the same motor.