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Doctor of Philosophy / Department of Electrical and Computer Engineering / Balasubramaniam Natarajan / Due to the underutilization of scarce radio spectrum resources, there is a major shift from an exclusive use model to a spectrum sharing model. This model has been successful in unlicensed bands where wireless standards such as Bluetooth and WLAN IEEE802.11 have flourished. In order to extend this model to licensed bands, a smart radio is required. The cognitive radio is a smart radio that leverages its knowledge of the local environment in order to operate with acceptable interference to primary users in the band. The brain of the cognitive radio is encapsulated in the sensing receiver. Using the sensing receiver, the cognitive radio observes the activity in a band and adapts its communication link parameters so that the interference is minimal. The sensing receiver attributes include wideband operation and agility. The receiver must be able to make fast decisions accurately of the spectrum activities. To date, a practical sensing receiver has been a major stumbling block in the realization of cognitive radio. In our research, we demonstrate that a practical sensing receiver is in fact feasible. Our research objectives are: (1) to develop a sensing receiver based on current technology, and (2) to augment our solution with an associated algorithm that makes fast and accurate sensing possible. Our proposed solution is a Dedicated Sensing Receiver (DSR) that employs an adaptive algorithm to enable the cognitive radio to effectively operate in a competitive environment. The DSR algorithm divides the frequency band into coarse sensing bins which are further divided into fine sensing bins. We derive a mathematical model that is optimized for minimizing sensing time. The optimization algorithm generates the optimum number of coarse and fine sensing bins based on environment conditions and the radio implementation. Our results illustrate the DSR’s ability to reduce open spectrum recognition time by over 10X while operating over a broad range of frequencies. This drastic improvement opens the door for the cognitive radio technology to be used in commercial applications in the near future and more importantly, it allows for the cognitive radio to succeed in time sensitive applications such as voice or video. We have also developed an end to end simulation platform to model the algorithm and the dedicated sensing receiver performance.

International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / Combined with an example of digital telemetry receiver design, this paper mainly discusses the application of software radio in telemetry receiver. The paper begins with an introduction of applying high efficiency digital filter and math analysis in quadrature digital frequency modulation and demodulation to digital frequency conversion technique. Next, Simulink/Matlab is used to simulate digital telemetry receiver. The method of simulation, analysis and calculation of performance and result of simulation are all available. In the end, the paper discusses digital telemetry receiver design and implement by making use of software radio technique, the circuits apply HSP50214 chip of Intersil Co., CPLD implements of Altera Co. and PC Bus. The sample is an expansion card for personal computer. Result of test, performance of the receiver and conclusion are given out, which show fine performance of receiver and can be apply to practice. The lever of this technology has reached first class in the world.

International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / Off-line software based signal analysis can be a valuable tool for detailed examination of transmitter signal characteristics. This paper describes the Advanced Range Telemetry (ARTM) Constant Envelope (CE) offset quadrature phase shift keying (OQPSK) modulation analyzer. It was developed expressly for evaluation of FQPSK-B^(1), FQPSK-JR and shaped OQPSK transmitter signals. Rationale for its creation, underlying assumptions, computation methods, and examples of its data products are presented.

The Boxall Profile (BP) aims at assessing the quality of adaptation of primary school pupils along with their particular difficulties of adaptation, in order to guide teacher interventions in classroom. At this time, the BP's psychometric proprieties have not been studied much. 169 boys and 23 girls ( N = 192) ranging from 6 to 13 years old (M = 9.24 years old, SD = 1.83) were assessed by their teacher using the French versions of the Boxall Profile, the Strenghts and Difficulties Questionnaire (SDQ) and the Teacher Report Form (TRF). Confirmatory and exploratory factor analysis (CFA/EFA) and area under receiver operating characteristic curve (ROC) were all performed. The results support the fit of the first level of factorial structure and a good concurrent validity. These results suggest the effectiveness of BP in properly identifying pupils in a problematic situation. However, one has to be cautious when it comes to interpreting given scale's scores to guide the intervention.

ITC/USA 2008 Conference Proceedings / The Forty-Fourth Annual International Telemetering Conference and Technical Exhibition / October 27-30, 2008 / Town and Country Resort & Convention Center, San Diego, California / Enclosed weapon bays on modern aircraft interfere with prelaunch, Flight Termination System verification during training test launches. Range safety personnel need to verify the functionality of the flight termination system prior to missile launch. The missile telemetry RF is highly attenuated when the aircraft missile bay doors are closed, limiting the range for which the aircraft can fly during training flights. Teletronics Technology Corporation and Lockheed Martin designed a system to provide telemetry data for these aircraft. The system re-radiates the telemetry from the missiles with the weapon bay doors closed. This paper describes the design considerations for this flexible system that accommodates multiple weapon systems in multiple weapon bay configurations.

ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Despite the inherent resistance to narrowband signal interference afforded by GPS spread spectrum modulation, the low level of GPS signals makes them susceptible to narrowband interference. This paper discusses the application of a pre-correlation adaptive temporal filter for stationary and nonstationary narrowband interference suppression. Various adaptive algorithms are studied and implemented. Comparison of the convergence and tracking behavior of various algorithms is made.

International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, California / With the increased concerns for reducing cost and improving reliability in today's telemetry systems, many users are employing simulation and automation to guarantee reliable telemetry systems operation. This places an increased demand on the remote capabilities of the equipment used in the telemetry system. Furthermore, emphasis has been placed on the ability to decrease the space and power consumption of the telemetry system to facilitate transportability of the a single telemetry system to multiple sites. Finally, today's telemetry systems demand that all equipment provide multiple functions to provide the maximum performance for the lowest system cost.

International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / A parallel multi-channel receiver for binary phase shift keyed (BPSK) direct-sequence (DS) spread-spectrum (SS) is introduced in this paper. It adopts a Costas carrier frequency-tracking loop which maintains frequency lock rather than phase lock, and the delay-lock error can be noncoherently obtained to track the PN code. For airborne applications, this method will extend effectively the receiver’s tracking dynamics range for the carrier Doppler shift. A erasable programmable logic device (EPLD) is applied to get the advantage of smaller size and higher flexibility. A high speed microprocessor (TMS320C30) which acts as the processing unit of the receiver is used for acquiring and tracking of the carrier and PN code by digital signal processing algorithms. This receiver is more flexible and is easily improved by reconfiguring the EPLD and modifying the software algorithms. Its fundamental principle is described in the paper.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / An integrated design, Test and Evaluation (T&E) system for GPS receiver is proposed in the paper, which can perform T&E early in R&D cycle, and combine new designs into a conceptual GPS receiver directly. The flowchart of its development mode is given. The architectures of the system, especially of the signal-computing software are described with frame diagrams. The mathematical models of three reference points are derived, with the impact of oscillator errors modeled. Future plans and further developments are also discussed.