International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, California / Some Telemetry systems today receive a binary phase shift keying modulation format. Typically, to demodulate BPSK requires using a carrier synchronizer followed by a bit synchronizer. Demodulation of BPSK can be accomplished using digital signal processing techniques to implement both synchronizers. This paper describes a digital system that demodulates a 16 KHZ, 2KBPS BPSK signal. In order to evaluate these techniques, the theory of operation was evaluated. Additionally, a computer simulation of the demodulator was developed. The computer simulation was implemented using Pascal. The techniques were optimized to give maximum performance while requiring minimum hardware and power in an actual implementation.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / To make the DGPS data link can be easily modified and updated, the ‘software radio’ technology becomes a logical architecture choice applying in a DGPS transceiver. This paper will discuss the system architecture and the key technology of software DGPS transceiver, which will become a multi-band and multi-function transceiver. It will operate at the uniform hardware platform to realize two receivers’ functions ¾ both the GPS receiver and the data link receiver (or transmitter). Then, this paper will give the design and implementation of the transceiver. Finally, it will demonstrate the simulation results of the system.

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Typescript (photocopy). / Digitized by Kansas Correctional Industries

Estimating the carrier frequency from a modulated waveform is one of the most important functions of a coherent signal receiver. Good performance and low bit error rates are obtained by coherent demodulation. Therefore, exact knowledge of the received signal carrier frequency is critical for communication systems. Also due to the spectral crowding, a high probability of channel interference can be observed. Under moderate carrier frequency offsets, data-aided estimators have been developed which have a high accuracy of estimation. However, for high frequency offsets the frequency estimator does not have the information of data or timing. In this thesis we propose a parametric based carrier frequency estimation of GMSK, which has improved performance over ad-hoc methods (delay and multiply) and has high resolution capability. In this thesis three methods are implemented over GMSK data to improve the performance and their results compared with the standard delay and multiply method. Two of these methods are parametric based estimators and one is a fast frequency estimator. Parametric based estimators were chosen partly due to their high resolution capabilities and mainly for their proven performance. Parametric based estimators were seen to have high computational load, and hence an alternate fast frequency estimator was implemented. The tradeoffs involved with respect to computational load and performance were shown. The contributions of this thesis include the verification of the validity of applying a parametric based approach on GMSK data, and compare the performances of parametric methods and fast frequency estimator. It is showii that such an approach has a better performance compared to non-data aided ad-hoc delay. and multiply methods. A closed loop configuration of the open loop parametric methods is suggested in the end. / Graduation date: 2004 / Best scan available. Figures are light on the original.

Simulation is the process of computing a behavior determined by a given model of a system of interest.  Modeling is the process of creating a model that formally describes a given class of system.  Modeling and simulation can be used to quickly and cheaply study and understand new technologies.  Today, a wide range of systems are simulated using different tools.  However, converting models into simulation codes can still be difficult and time consuming. In this thesis, we study how a new modeling and simulation language called Acumen can be used to model basic physical links.  This language is aimed at bridging the gap between modeling and simulation.  We focus on basic physical links as an interesting type of system to model and simulate. We also focus on comparing Acumen to MATLAB and Simulink.  The types of links we consider include models of an RC low-pass filter, Amplitude Modulation, Frequency Modulation, Amplitude Shift Keying, Phase Shift Keying and Frequency Shift Keying systems. Each of these examples is modeled in Acumen, MATLAB and Simulink. We find that, for the most part, Acumen allows us to naturally express a wide range of modulation techniques mentioned above. When compared to MATLAB ad Simulink, we find that Acumen is simple language to understand. Acumen codes are described in a more natural way. Simplicity is the biggest advantage of Acumen.

Because the acoustic wave is capable of propagating at a long-distance in water, the hydrophone plays a key role in the underwater acoustic sensing all the time. The hydrophone based on fiber optic interferometry has an extremely high sensitivity and large dynamic range. In addition, the electrically passive, immunity to electromagnetic interference, and multiplexing properties of fiber optic sensor offer great advantages over traditional piezoelectric hydrophone. Due to the complete path-balance between the two counterpropagating waves, a Sagnac interferometric configuration can employ a low-coherent light source to reduce the cost. This configuration can easily route optical paths and replace sensor heads to compare with each other. But, the sensitivity varying with frequency and the polarization-induced signal fading problem make it unsuitable for applications in need of detecting correct amplitude of signals. The Michelson interferometric configuration with Farady rotator mirror (FRM) has a constant sensitivity and solves the polarization-induced signal fading problem. But, this configuration uses a high-coherent light source and expensive FRMs, and be difficult to route. In this paper, we use the polarization-insensitive Michelson fiber optic sensor to adjust the demodulation circuits we design. In this paper, we establish the interferometric hydrophones. The fiber optic coil of the sensor head is embedded with the special materials in order to acoustic impedance matching and waterproofing. We employ phase generated carrier demodulation technology to get the acoustic signal of interest from the output of the interferometer. In our experiment, the dual Sagnac configuration has a dynamic range of 23 dB and a sensitivity of -226 dB re V/1uPa, the Michelson configuration with FRMs has a dynamic range of 25 dB and a sensitivity of -204 dB re V/1uPa.

Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, December 2009. / Thesis Advisor(s): Jenn, David C. Second Reader: Pace, Phillip E. "December 2009." Description based on title screen as viewed on January 28, 2010. Author(s) subject terms: Direct conversion, homodyne, IQ mismatch, DC offsets, IQ circle, phase error, modulator, demodulator calibration, LabVIEW, Directional Finding (DF), digital beamforming, Robust Symmetrical Number System (RSNS). Includes bibliographical references (p. 73-75). Also available in print.

Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2002. / Includes bibliographical references (leaves 111-117). Also available in electronic version. Access restricted to campus users.

Σκοπός της παρούσας διπλωματικής ήταν η μελέτη μιας νέας ιδέας ψηφιακής διαμόρφωσης – αποδιαμόρφωσης σήματος. Με την νέα αυτή μέθοδο το φέρον σήμα διαμορφώνεται κατά πλάτος, συχνότητα και φάση. Η αποδιαμόρφωση δεν γίνεται με καμία από τις κλασσικές και ευρέως χρησιμοποιούμενες τεχνικές αλλά με μία νέα και πολλά υποσχόμενη μέθοδο. Τα χαρακτηριστικά αυτής της νέας μεθόδου μας ώθησαν να την μελετήσουμε σε βάθος για να διαπιστώσουμε τις δυνατότητες της και την αποτελεσματικότητα της. Η μελέτη της μεθόδου, πραγματοποιήθηκε σχεδιάζοντας το σύστημα διαμόρφωσης – αποδιαμόρφωσης στο εργαλείο MATLAB και κάνοντας σε κάθε βήμα του σχεδιασμού εξομοιώσεις λειτουργίας του συστήματος. Τα αποτελέσματα των εξομοιώσεων και η απόδοση του συστήματος παρουσία θορύβου μας βοήθησαν να κάνουμε διαφόρων ειδών βελτιστοποιήσεις στην εφαρμογή της μεθόδου. Η μέθοδος τελικά αποδείχτηκε ιδιαίτερα αποτελεσματική και αξιόπιστη ενώ και η απόδοση της παρουσία θορύβου ήταν πάρα πολύ καλή και συγκρίσιμη αν όχι και καλύτερη από τις υπάρχουσες μεθόδους. / In this project, we studied, designed and implemented a new method for digital signal modulation demodulaion. The Project’s aim was the development and evaluation of a new frequency, amplitude and phase demodulation method, which applies simple processing on triplets of samples to compute the characteristics of the incoming signal. The derived demodulation system has a wide dynamic range on the input signal and additionally, estimates the instantaneous input frequency, phase and amplitude extremely fast and with good resolution.