International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / Feher Keying (FK) signals are clock shaped baseband waveforms with the potential to attain very high spectral efficiencies. Two FK signals which have different level rectangular waveforms (named as FK-1) or sinusoidal waveforms (named as FK-2) for two binary symbols are considered in this paper. These signals have periodic components in the time domain. Therefore they have cyclostationary properties. This means that spectral correlation exists in the frequency domain. For each type of waveforms, spectral correlation has been investigated. FK signals can be expressed mathematically into two parts in the frequency domain – discrete part and continuous part. The discrete part has one or more discrete impulse(s) in their spectra and the continuous part has periodically the same shape of harmonics in their spectra. The correlations of their spectra have been obtained mathematically and by simulation. It is shown that FK signals have high correlation related to the symbol rate. Finally, some suggestions how these properties can be used to improve their performance by devising better demodulators are discussed. These properties can be used for interference rejection at the receiver, which results in low bit error rate performance.

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Shock and vibration testing was performed on the Metrum-Datatape Inc. 32HE recorder to determine its viability as an airborne instrumentation recorder. A secondary goal of the testing was to characterize the recorder operational shock and vibration envelope. Both flight testing and laboratory environmental testing of the recorder was performed to make these determinations. This paper addresses the laboratory portion of the shock and vibration testing and addresses the test methodology and rationale, test set-up, results, challenges, and lessons learned.

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / The Bit Error Rate (BER) performance of FQPSK modulated signals in the presence of the Co-Channel Interference (CCI) and Additive White Gaussian Noise (AWGN) is evaluated and improved. A Non- Linearly Amplified (NLA) FQPSK modulated signal with the data rate of 1Mb/s and carrier frequency of 70 MHz is interfered with a sinusoidal signal at different frequencies. As the relative distance of the center frequency of the Co-channel interference (CCI) changes, different BER are obtained. The effect of the CCI decreases as the CCI center frequency moves away from the center of the modulated signal. In order to improve the BER in the presence of the CCI, a hard limited filter is added at the receiver input. The hard limited filter has a different amplification factor for different signal strength. As a result, the amplification factor for the CCI, which is normally a weaker signal, is smaller than the actual signal. This means that the signal is amplified more than the interference and as a result the CCI is suppressed and the BER rate improves. The results of both simulations and measurements are obtained for different CCI center frequencies, before and after the improvements.

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / High explosive radio telemetry (HERT) is a project that is being developed jointly by Los Alamos National Laboratory and AlliedSignal FM&T. The ultimate goal is to develop a small, modular telemetry system capable of high-speed detection of explosive events, with an accuracy on the order of 10 nanoseconds. The reliable telemetry of this data, from a high-speed missile trajectory, is a very challenging opportunity. All captured data must be transmitted in less than 20 microseconds of time duration. This requires a high bits/Hertz microwave telemetry modulation code to insure transmission of the data within the limited time interval available.

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / Incidental Frequency Modulation (IFM) products in telemetry transmitters can be a significant cause of bit errors in received Pulse Code Modulation/Frequency Modulation (PCM/FM) telemetry data. Range Commanders Council (RCC) and other documents give little or no guidance as to acceptable levels of IFM for telemetry applications. The expected higher vibration levels of future high velocity missile systems means that IFM levels are likely to be higher than previously encountered. This paper presents measured data on Bit Error Rate (BER) versus IFM levels at given Signal to Noise Ratios (SNR’s) for PCM/FM telemetry systems. The information presented can be utilized with BER versus SNR plots in the Telemetry Applications Handbook, RCC Document 119, to determine the additional link margin required to minimize IFM effects on telemetry data quality.

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / The future of range operations in the area of expendable launch vehicle (ELV) support is unquestionably headed in the direction of space-based rather than land- or air-based assets for such functions as metric tracking or telemetry data collection. To this end, an effort was recently completed by the Air Force’s Eastern Range (ER) to certify NASA’s Tracking and Data Relay Satellite System (TDRSS) as a viable and operational asset to be used for telemetry coverage during future Titan IV/Centaur launches. The test plan developed to demonstrate this capability consisted of three parts: 1) a bit error rate test; 2) a bit-by-bit compare of data recorded via conventional means vice the TDRSS network while the vehicle was radiating in a fixed position from the pad; and 3) an in-flight demonstration to ensure positive radio frequency (RF) link and usable data during critical periods of telemetry collection. The subsequent approval by the Air Force of this approach allows future launch vehicle contractors a relatively inexpensive and reliable means of telemetry data collection even when launch trajectories are out of sight of land-based assets or when land- or aircraft-based assets are not available for support.

International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Performances of a subclass of a new spectral efficient modulation scheme, designated as Feher Keying [1], or FK, is evaluated. The Power Spectral Density (PSD) and Bit Error Rate (BER) characteristics of FK are presented. FK has ultra high spectral efficiency and satisfies the frequency mask for WLAN defined in FCC part 15, and it has a simple structure for high bit rate implementation.

In the cooperative communications, the users relay each other¡¦s signal and thus forming multiple transmission paths to the destination and therefore the system can achieve spatial diversity gain. Decode-and-forward and amplify-and-forward are the most popular relaying strategies in the literature due to their simplicity. However, in practice, cooperative users acting as relays may not always normally operated or trustworthy. When the relay misbehavior is present in the cooperative networks, the communication performance may degrade dramatically and the users may be even better off without cooperation. Therefore, it is necessary for the destination to determine the misbehaving relays and to take appropriate actions to ensure that cooperative advantages are preserved. In this thesis, we focus on developing a misbehaving relay detection method to detect whether or not the system is in the presence of some misbehaving relays. After performing misbehaving relay detection, the destination removes the signals from the un- reliable paths and then uses maximal ratio combing to achieve spatial diversity. The simulation results conducted by the thesis show that the proposed method is more robust as compared with those without employing misbehaving relay detection when the system is in the presence of some misbehaving relays.

In the cooperative communications, the users relay each other's signal and thus form multiple transmission paths to the destination and therefore the system can achieve spatial diversity gain. Most studies in the literature assumed that cooperative users acting as the relays are normally operated and trustworthy. However, this may not always be true in practice. When the relay misbehaviors are present in the cooperative communications, the communication performance may degrade dramatically and the users may be even better off without cooperation. Therefore, it is necessary for the destination to determine the misbehaving relays and to take appropriate actions to ensure that cooperative advantages are preserved. This thesis considers both models in which the cooperative communications are with direct path (WDP) and without direct path (WODP). Utilizing the proposed Kolmogorov-Smirnov test mechanism, the destination identifies the misbehaving relays within the cooperative communications and then excludes their transmitting messages when performing the diversity combining to infer the symbols of interest sent by the source. In addition, this thesis provides the bit error rate (BER) analysis of the cooperative communications employing the proposed misbehaving relay detectors. The simulation results demonstrate that the proposed methods have robust performance when the relay misbehaviors are present in the cooperative communications.

The Motorola Inc. paging protocol FLEX is discussed. The design and construction of a FLEX paging protocol decoder is discussed in detail. It proposes a decoding solution that includes a radio frequency (RF) receiver and a decoder board. The RF receiver will be briefly discussed. The decoder design is the main focus of this thesis as it transforms the RF frequency modulated (FM) data from the receiver and converts it to FLEX data words. The decoder is designed to handle bit sampling, bit clock synchronization, FLEX packet detection, and FLEX data word collection. The FLEX data words are then sent by the decoder to an external computer through a serial link for bit processing and storage. A FLEX transmitter will send randomly generated data so that a bit error rate (BER) calculation can be made at a PC. Each receiver'9s noise power and noise bandwidth will be measured so that noise spectral density may be calculated. A complete measurement set-up will be shown on how these noise measurements are made. The BER at a known power level is recorded. This enables Eb/No curves to be generated so that results of the decoding algorithm may be compared. This is performed on two different receivers. / Master of Science