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Articles 1 - 7 of 7
Full-Text Articles in Engineering
Effects Of Piconet Saturation On A Bluetooth Streaming Audio Channel, Theodore L. Josue
Effects Of Piconet Saturation On A Bluetooth Streaming Audio Channel, Theodore L. Josue
Theses and Dissertations
Bluetooth is a technology for wireless personal area networks (WPAN) that eliminates the need for cables, standardizes interfaces, and can automate many standard office processes such as sending and receiving email, synchronizing schedules, or exchanging business cards. With each workstation creating its own Bluetooth network, called a piconet, different Air Force environments have the potential, in some cases, to create more than 50 overlapping piconets, which significantly increases the potential for inter-piconet interference. This research investigates the effects of inter-piconet interference on a Bluetooth channel, streaming audio, offered at 24, 40, and 64 Kbps. It shows that as the number …
Insulator Charging In Rf Mems Capacitive Switches, Jay F. Kucko
Insulator Charging In Rf Mems Capacitive Switches, Jay F. Kucko
Theses and Dissertations
While capacitive radio frequency microelectromechanical (RF MEM) switches are poised to provide a low cost, high isolation, low power alternative to current RF switch technologies, there are still reliability issues limiting switch lifetime. Previous research identified insulator charging as a primary cause of switch failure. Changes in switch pull-in and release voltages were measured to provide insight into the mechanisms responsible for charging and switch failure. A spatial and temporal dependent model was developed to describe silicon nitride's time-dependent charging as a function of applied bias. This model was verified by applying constant biases to metal-silicon nitride-silicon capacitors and tracking …
Capacitance-Voltage Study On The Effects Of Low Energy Electron Radiation On Al0.27Ga0.73N/Gan High Electron Mobility Transistor, Thomas D. Jarzen
Capacitance-Voltage Study On The Effects Of Low Energy Electron Radiation On Al0.27Ga0.73N/Gan High Electron Mobility Transistor, Thomas D. Jarzen
Theses and Dissertations
The effects of radiation on semiconductors are extremely important to the Department of Defense since the majority of the defense informational, navigational and communications systems are now satellite-based. Due to the high radiation tolerance of gallium nitride and a plethora of high temperature, high power and high frequency applications, the prospect that gallium nitride based devices will become key components in a multitude of military satellite-based systems is highly probable. AlGaN/GaN HEMTs were irradiated at low temperature (~80 K) by 0.45 – 0.8 MeV electrons up to fluences of 1×1015 e-/cm2. Following irradiation, low temperature capacitance-voltage measurements …
Finite Difference Time Domain (Fdtd) Analysis Of A Leaky Traveling Wave Microstrip Antenna, Gregory M. Zelinski
Finite Difference Time Domain (Fdtd) Analysis Of A Leaky Traveling Wave Microstrip Antenna, Gregory M. Zelinski
Theses and Dissertations
This thesis provides the groundwork that will enable the development of a lightweight, inexpensive, aerodynamic, and broadband antenna. Whether for radar or communication, an antenna with these properties would be a force multiplier for the smaller, limited payload air vehicles the United States Air Force will pursue in the coming years. Several microstrip antennas using the first higher order mode were simulated with the Finite-Difference Time-Domain (FDTD) method. The propagation constant of each antenna was extracted from the resulting field distribution for comparison with a transverse resonance approximation, measured far-field patterns, and other simulated antennas. Variations of the geometry were …
Multiple Model Adaptive Estimator Target Tracker For Maneuvering Targets In Clutter, Brian D. Smith
Multiple Model Adaptive Estimator Target Tracker For Maneuvering Targets In Clutter, Brian D. Smith
Theses and Dissertations
The task of tracking a target in the presence of measurement clutter is a two-fold problem: one of handling measurement association uncertainty (due to clutter), and poorly known or significantly varying target dynamics. Measurement association uncertainty does not allow conventional tracking algorithms (such as Kalman filters) to be implemented directly. Poorly known or varying target dynamics complicate the design of any tracking filter, and filters using only a single dynamics model can rarely handle anything beyond the most benign target maneuvers. In recent years, the Multiple Hypothesis Tracker (MHT) has gained acceptance as a means of handling targets in a …
Head Tracking For 3d Audio Using A Gps-Aided Mems Imu, Jacque M. Joffrion
Head Tracking For 3d Audio Using A Gps-Aided Mems Imu, Jacque M. Joffrion
Theses and Dissertations
Audio systems have been developed which use stereo headphones to project sound in three dimensions. When using these 3D audio systems, audio cues sound like they are originating from a particular direction. There is a desire to apply 3D audio to general aviation applications, such as projecting control tower transmissions in the direction of the tower or providing an audio orientation cue for VFR pilots who find themselves in emergency zero-visibility conditions. 3D audio systems, however, require real-time knowledge of the pilot's head orientation in order to be effective. This research describes the development and testing of a low-cost head …
Modification Of A Modulation Recognition Algorithm To Enable Multi-Carrier Recognition, Angela M. Waters
Modification Of A Modulation Recognition Algorithm To Enable Multi-Carrier Recognition, Angela M. Waters
Theses and Dissertations
Modulation recognition is important for both military and commercial communication applications, particularly in cases where enhanced situation awareness and/or channel assessment is required to mitigate intentional or collateral interference. Modulation recognition via template matching or statistical analysis is a key aspect of non-cooperative (nonmatched filtering) signal interception, classification, and exploitation. This research concerns the evaluation and modification of a conventional Digitally Modulated Signal Recognition Algorithm (DMRA) to enable multi-carrier, Orthogonal Frequency Division Multiplexing (OFDM), waveform recognition. The original DMRA architecture was developed to classify communication signals for three fundamental data modulations, i.e., Amplitude Shift Keying (ASK), Phase Shift Keying (PSK), …