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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

LABORATORY INVESTIGATION INTO FQPSK OPERATIONAL CHARACTERSITICS

Wegener, John A. 10 1900 (has links)
International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Due to increasing data rates required for Flight Test telemetry on upcoming programs, and because of increasing competition for spectrum space, Boeing Integrated Defense Systems (IDS) Flight Test in Saint Louis is considering use of the Feher-patented Quadrature Phase Shift Keying (FQPSK) modulation scheme. To determine potential operational issues associated with FQPSK, Boeing IDS Flight Test initiated a laboratory investigation of FQPSK using commercially available equipment including a transmitter from Herley and a demodulator from RF Networks. This paper describes the results of this laboratory investigation, including spectrum occupancy, bit-error rate performance, demodulator acquisition performance, demodulator bit-rate tracking, demodulator pattern sensitivity, and other operational characteristics.
2

SMALL VOLUME, FEHER-PATENTED QUADRATURE PHASE SHIFT KEYING, JR VERSION, TELEMETRY TRANSMITTER

Bottenfield, Joe, Moore, Vern 10 1900 (has links)
International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper describes the implementation of a Feher-Patented Quadrature Phase Shift Keying (FQPSK) waveform variant that reduces overall design complexity, which in turn results in a telemetry transmitter that provides all the benefits of the existing FQPSK-B waveform, in a 3.0 x 2.0 x 1.0 volume. This variant is referred to the as the FQPSK-JR version. This waveform differs from the “near constant” envelop response of the qualified Herley airborne FQPSK-B telemetry transmitter in terms of the time domain wavelet transition functions and the amplitude scaling term associated with those functions. The end result is a “constant envelop” design, which employs simplified antialias filtering and more efficient digital design techniques.
3

EVALUATION OF CONSTANT ENVELOPE OFFSET QUADRATURE PHASE SHIFT KEYING TRANSMITTERS WITH A SOFTWARE BASED SIGNAL ANALYZER

Jefferis, Robert P. 10 1900 (has links)
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.
4

FQPSK-B Baseband Filter Alternatives

Jefferis, Robert 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / Designers of small airborne FQPSK-B (-B) transmitters face at least two significant challenges. First, many U.S. Department of Defense (DOD) test applications require that transmitters accommodate a continuum of data rates from 1, to at least 20 Mb/s in one design. Another challenge stems from the need to package a high-speed digital baseband signal generator in very close proximity to radio frequency (RF) circuitry required for 1.4 to 2.4 GHz operation. The -B baseband filter options prescribed by Digcom/Feher [2] are a major contributor to variable data rate design challenges. This paper summarizes a study of -B filter alternatives and introduces FQPSK-JR (JR), an alternative to -B that can simplify digital baseband transmitter designs. Very short impulse response digital filters are used to produce essentially the same spectral efficiency and nonlinear amplifier (NLA) compatibility as -B while preserving or improving detection efficiency (DE). In addition, a strategy for eliminating baseband shaping filters is briefly discussed. New signaling wavelets and, modified wavelet versus symbol sequence mapping rules associated with them, can be captured from a wide range of alternative filter designs.
5

INTERFERENCE CANCELLATION USING ARTM TIER-1 WAVEFORMS IN AERONAUTICAL TELEMETRY

Ali, Tariq M., Saquib, Mohammad, Rice, Michael 10 1900 (has links)
ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / This paper describes and interference cancellation technique appropriate for ARTM Tier-1 waveforms. The technique requires the estimators for the bit sequences for the adjacent channels as well as the power levels of the adjacent channels. Simulation results show that the interference canceller allows a more dense “channel packing” thereby creating a channel utilization 67% ~ 100% greater than the current IRIG 106 recommendations.
6

IN-SERVICE DETECTION OF MULTIPATH FADING

Jefferis, Robert 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / Multipath (MP) fading is the dominant channel impairment in many aeronautical telemetry links. One product of a recent multipath mitigation study is the discovery of a simple technique for detecting its presence over a useful range of conditions. The technique also detects significant random noise levels in the channel. This paper describes the “Signal Degradation Indicator” (SDI) and its application to FQPSK-B and SOQPSK [2] modulation. Laboratory emulation data is presented and implementation considerations are discussed.
7

COMMON DETECTORS FOR TIER 1 MODULATIONS

Nelson, Tom, Perrins, Erik, Rice, Michael 10 1900 (has links)
ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / The ARTM Tier 1 waveforms include two versions of Feher patented QPSK (FQPSK-B and FQPSK-JR) and a version of shaped offset QPSK (SOQPSK-TG). In this paper we examine three common detector architectures for the ARTM Tier 1 modulations: a symbol-by-symbol detector, a cross correlated trellis coded modulation (XTCQM) detector, and a continuous phase modulation (CPM) detector. We show that when used to detect Tier 1 modulations, these detectors perform well even without knowledge of the modulation used by the transmitter. The common symbol-by-symbol detector suffers a loss of 1.5 dB for SOQPSK-TG and 1.6 dB for FQPSK-JR in bit error rate performance relative to the theoretical optimum for these modulations. The common XTCQM detector provides a bit error rate performance that is 0.1 dB worse than optimum for SOQPSK-TG and that matches optimum performance for FQPSK-JR. The common CPM detector achieves a bit error rate performance that is 0.25 dB worse than optimum for SOQPSK-TG and that approximately matches optimum for FQPSK-JR. The common XTCQM detector provides the best bit error rate performance, but this detector also has the highest complexity.
8

RECOMMENDED MINIMUM TELEMETRY FREQUENCY SPACING WITH CPFSK, CPM, SOQPSK, AND FQPSK SIGNALS

Law, Eugene 10 1900 (has links)
International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper will present equations for calculating the minimum recommended frequency separation of two digital telemetry signals. The signals can be filtered continuous phase frequency shift keying (CPFSK), multi-h continuous phase modulation (CPM) [1], shaped offset quadrature phase shift keying-Telemetry Group (SOQPSK-TG, aka SOQPSK-A*) [2], or Feher’s patented quadrature phase shift keying FQPSK-B (or FQPSK-JR [3]). The equations are based on measured data in an adjacent channel interference (ACI) environment for filtered CPFSK (aka PCM/FM), multi-h CPM (or CPM for short), SOQPSK-TG, FQPSK-JR, and FQPSK-B. This paper is an extension of my 2001 and 2002 International Telemetering Conference papers on this topic [4, 5]. The quantity measured was bit error probability (BEP) versus frequency separation at a given signal energy per bit to noise power spectral density ratio (Eb/No). The interferers were CPFSK, CPM, SOQPSK-TG or FQPSK-B (-JR) signals. The results presented in this paper will be for a desired signal bit rate of 1 to 20 Mb/s, one interferer 20 dB larger than the desired signal (a few tests included two interferers), and various center frequency spacings, interfering signals, receivers, and demodulators. The overall ACI test effort has collected data sets at several bit rates and with one and two interferers. The results will be useful to system designers and range operators as they attempt to maximize the number of Mb/s that can be simultaneously transmitted with minimal interference in the telemetry bands.
9

FQPSK ANALOG/DIGITAL IMPLEMENTATIONS FOR LOW TO ULTRA HIGH DATA RATES IN 1Gb/s RANGE SYSTEMS

Chen, Dijin, McCorduck, James A., Feher, Kamilo 10 1900 (has links)
International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / For simpler implementations of ultra high bit rate systems, combined analog/digital techniques, described here in, provide implementations with the smallest number of component count utilizing minimal “real-estate” and smallest DC power. While digital implementations with tradition Read Only Memory (ROM) and Digital to Analog Converters (DAC’s) have been proven in several commercial, NASA -CCSDS recommended, and U.S. DoD-IRIG standardized Feher’s QPSK (FQPSK) [2,3] products, such implementations can be further simplified, and in particular for ultra high bit rate product applications. Several waveform generating techniques such as linear approximation, analog approximation and mixed analog and linear approximations are investigated using preliminary simulation results.
10

IRIG FQPSK-B STANDARDIZATION PROGRESS REPORT

Law, Eugene L. 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / This paper will provide an overview of the process used to develop the bandwidth efficient modulation sections of the Inter-Range Instrumentation Group (IRIG) standard. The modulation method selected was Feher’s patented quadrature phase shift keying (FQPSK-B). The important characteristics of a bandwidth efficient modulation method for aeronautical telemetry will be presented first followed by a summary of the results of the research, laboratory test, and flight test efforts. Future plans will then be summarized followed by the FQPSK-B sections of the current IRIG Telemetry Standard (the standard is available online at: http://tecnet0.jcte.jcs.mil/RCC/oldoc.htm).

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