When the message sink of a speech communication system is a human, the ultimate criterion of system performance is the subjective quality of the output speech. Unfortunately, no tractable mathematical function has been found to adequately relate speech quality to the physical system parameters. For this reason, empirical methods must be utilized to assess the interplay between the subjective quality and the objective parameters of a speech communication system. In this thesis the effects of transmission errors on the speech quality of pulse code modulation (PCM) and differential pulse code modulation (DPCM) voice communication systems are investigated. The subjective figure of merit adopted in this study is the listener's preference of the output speech with respect to a suitably chosen reference. Under some assumptions and restrictions, the system models of the two types of modulation systems of interest are formulated and simulated in an IBM System 360/Model 67 time-shared computer. With the aid of a special-purpose input/output interface, the simulated systems are used to process a recorded speech sample representative of English speech. The quality of the processed speech is then subjectively evaluated according to the isopreference method. The results of the subjective evaluation are presented in the form of isopreference contours. These contours indicate that in both PCM and DPCM systems, the speech quality is dominantly influenced by quantization error when the channel is relatively error-free; whereas if the channel is relatively noisy, finer quantization offers no improvement in quality. Furthermore, encoding the quantizer's output by either natural or folded binary coding yields virtually identical speech quality. In a comparison with contours of constant system signal-to-distortion power ratio, the isopreference contours reveal that under some conditions, the system signal-to-distortion power ratio may be a reasonably adequate measure of human preference of speech. In terms of the minimum channel capacity required to achieve a desired speech quality, DPCM is found to perform better than PCM for three important channel models: the binary symmetric channel, the additive white Gaussian channel, and the Rayleigh fading channel with additive white Gaussian noise. In the latter two cases, the performance improvement of DPCM over PCM increases with increasing desired speech quality for the range of speech quality considered in this study. Finally, the implications of the subjective tests' results in two suboptimal operations are discussed. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

This thesis concerns itself with the study of the Minimum Shift Keying (MSK) modulation scheme. The aspects considered are its operation under non-linear conditions as well as an investigation into the hardware implementation of both coherent and non-coherent MSK modems. The literature on digital data transmission and MSK in particular is surveyed, and a comprehensive theoretical description of MSK is given. In addition, papers on the operation of MSK under non-linear conditions were studied, and their major findings are presented. Due to the lack of theory on the effects of incorrect modulation index on the error performance of MSK, an investigation into this avenue was performed. The design of a correction mechanism for maintaining the modulation index at its correct value is described, and aspects of its implementation are considered. Using the available literature, various modules of which a coherent MSK modem is comprised were developed, and their design is discussed. The design of a non-coherent MSK demodulator is also described.

This work reports a first attempt to measure the solar neutrino annual<br />flux modulation due to Earth\'s elliptical orbit with the Borexino detector. Borexino is a real-time calorimetric detector for low energy neutrino spectroscopy located in the underground laboratory of Gran Sasso, Italy. The experiment\'s main focus is the direct measurement of the 7Be solar neutrino flux of all flavors via neutrino-electron scattering in an ultra-pure scintillation liquid. The original goal of this work was to quantify sensitivity of the Borexino detector to a 7% peak-to-peak signal variation over the course of a year and study background stability. A Monte-Carlo simulated sample of the expected variation was prepared in two phases of data acquisition, Phase I that spans from May-2007 to May-2010 and Phase II from October-2011 to September-2012. The data was then fitted in the time domain with a sinusoidal function and analyzed with the Lomb-Scargle fast Fourier transformation in the search for significant periodicities between periods of 0.5 and 1.5 years. The search was performed in the energy window dominated by 7Be, [210; 760] keV, and 60-day bins in the case of the fit and 10-bins for the Lomb-Scargle scan. This work also contains study of the post-purification data of Phase II beyond September-2012 with a prediction for the future sensitivity and justification of the achieved background levels. / Ph. D.

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A special purpose modem has been designed to fill the interface requirements peculiar to RCA's DatawayTmk hotel/motel data management system. The modem interface operates on dedicated telephone quality wiring over distances up to 4000 feet using frequency shift keying. A data rate of 2880 bits per second is achieved through the interface. This report discussed the requirements of the interface and details the worst case design of the modem transmitter and receiver sections. The approach used relies heavily upon the use of digital logic circuitry in the modulation and demodulation of the FSK signals.

Several space vector modulation schemes have been analyzed for three-leg and four-leg voltage source inverters. The analysis is performed with respect to a) switching losses, b) total harmonic distortion, c) peak-to-peak ripple in the line current and d) the ease of digital implementation. The analysis is performed over the entire range of modulation index and for varying load power factors (leading and lagging) under both balanced and unbalanced load conditions. The analysis shows that the performance of four-leg inverters is similar to three-leg inverters for various space vector modulation schemes. The analysis also verifies the fact that a modulation scheme with good harmonic performance usually has high switching losses and vice-versa. The analysis is verified using simulation and experiments. A novel algorithm for the calculation of total harmonic distortion of PWM signals has been proposed. / Master of Science

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper presents the design of an innovative approach to Frequency Division Multiplexing (FDM) for the STRICOM Hardened Subminiature Telemetry and Sensor System (HSTSS) Data Acquisition Chipset (DAC) program. An ASIC (Application Specific Integrated Circuit) is being developed by Systems & Processes Engineering Corporation (SPEC) that implements this new digital FDM approach for telemetry applications. The FDM ASIC provides six channels that are IRIG-106 compatible, and may be used in conjunction with a Delay/Repeater ASIC. Together these ASICs make a complete instrumentation system for those applications requiring very small size, simplicity of use, and low cost, e.g. munitions/armament testing.

International Telemetering Conference Proceedings / October 30-November 02, 1989 / Town & Country Hotel & Convention Center, San Diego, California / Aydin Vector Division has developed and manufactured an airborne, high shock, wideband FM/FM telemetry system for Saab Missiles AB in Sweden. This system was presented in the ITC Proceedings of 1988, Volume XXIV, pp 71-84 (Ref [1]). Three such systems were supplied. Saab Missiles AB also awarded Aydin Vector Division with an additional order for a larger number of high shock, computer based, specially designed, miniature PCM/FM airborne telemetry systems. These systems were developed, manufactured and supplied to Saab Missiles AB, and have been extensively and successfully used in the Swedish program. The PCM/FM telemetry package described in this paper was used for the system testing and the firing trials program of a mortar projectile, where the measurement requirements included micro processor interfaces, as well as a high amount of analog and bi-level data channels. The paper covers the specifications of the PCM/FM system mentioned above, the concept that was used to meet these specifications, the system’s mechanical and electrical design, the packaging technique and some of the test results.