Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 35 for “"Digital modulation"”.
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Investigation into PRS-precoded, constant-envelope, continuous-phase digital modulation schemes
… properties of Pulse Amplitude Modulated (PAM) digital transmission systems. This thesis investigation studied the effect of PRS on frequency- and phase-modulated carrier systems, in particular on their spectral performance and their maintenance of constant envelope.
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An investigation into the performance capabilities of multi-h CPFSK digital modulation
… the performance capabilities of multi-h CPFSK digital modulation. Multi-h CPFSK is a coded modulation scheme. It exhibits high bandwidth efficiency and good envelope properties and is therefore well suited to use in satellite communications channels. However, the power efficiency of multi-h …
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Enhanced digital modulation of coherently coupled vertical cavity laser arrays: theory and application
… Directly modulated VCSELs are the dominant digital light source in short-haul data communication links due to their low cost and low operating power. Due to the demand for faster internet speeds and high-performance data centers, there is an ever-increasing need for high-bandwidth, …
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Digital power line communication on EHV power lines
Digital modulation can be used on PLC communication links to increase system capacity. The improved noise and interference capability of digital modulation can lead to reduced guard distances between co-channel users and can more than offset the additional bandwidth requirements of digital …
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Digital demodulation techniques for radio channels
… are not adequate. This research will examine a digital modulation scheme which can co-exist with an analog system. The generation of the digital modulation will be examined in terms of Adjacent Channel Interference (ACI) requirements. Simulation techniques for the mobile radio channel are …
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Modulation approaches of vertical-cavity surface-emitting lasers with mode control
… and device lifetime, various approaches of digital modulation utilizing VCSELs with modified structures for mode control are presented. Direct modulation of VCSELs with separate optical and current apertures enables high modulation bandwidth of greater than 18 GHz operating single mode at …
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Process Development for High Speed Transistor Laser Operation
… Small signal bandwidth of 20 GHz and digital modulation of 20 Gbit/s was obtained by reducing or eliminating extrinsic parasitics which limit device performance through the optimization of device geometry and process conditions.
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Low-power amplifier chopper stabilization for a digital-to-analog converter
… and low-noise performance from the internal digital-to-analog converter. CMOS design has allowed for oversampling sigma-delta modulation to achieve these goals. However, noise is typically limited by the kT/C noise in the switched capacitor filter following the digital modulation. These …
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An Underwater Channel Model and Chirp Slope Keying Modulation Scheme Performance
Chirp-Slope Keying (CSK) is a new and innovative digital modulation scheme for underwater data transmission. The underwater environment brings up several challenges to the manufacturing and operation of communication systems. This thesis shows through analysis and simulations the effectiveness of …
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PAPR reduction in OFDM communications with generalized discrete Fourier transform
… Shift Keying (QPSK) and 16 Quadrature Amplitude Modulation (16-QAM), digital modulation techniques are increased.
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Telecommunications for a deregulated power industry
… a power line channel model and the use of digital modulation techniques like SS and OFDM, which help overcome the effects of such a hostile medium of communication. (Abstract shortened by UMI.).
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Parameterized analysis of optical inter-satellite links for high resolution satellite communication
… of each are synthesized. Both analog and digital modulation schemes for the link are considered. A two-channel receiver with both low and high interference is analyzed. It is shown that high resolution satellite array receivers are practical with low required optical power. The optimum …
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Performance evaluation of chirp spread spectrum system and Land Mobile Satellite System by computer simulation
… Land Mobile Satellite System (LMSS) channel as a digital communications system. For the simulation of analog communications, a spread spectrum system using chirp techniques called ‘Coded Multiple Chirp Spread Spectrum’ was proposed as a simple, cost-effective alternative for conventional spread …
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Delta-Sigma digital-RF modulation for high data rate transmitters
… transmitter utilizing [Delta]-[Sigma] direct digital modulation of an RF carrier is presented. The transmitter architecture replaces high dynamic range analog circuits with high speed digital circuits and a passive LC bandpass filter, saving power and area compared to conventional IQ …
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Modulation classification of digital communication signals
Modulation classification of digital communications signals plays an important role in both military and civilian sectors. It has the potential of replacing several receivers with one universal receiver. An automatic modulation classifier can be defined as a system that automatically identifies the …
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A Novel Chirp Slope Keying Modulation Scheme for Underwater Communication
A digital modulation method using Chirp-Slope Keying (CSK) is developed for coherent underwater acoustic communications. Effective signal detection is a critical stage in the implementation of any communications system; we will see that CSK solves some significant challenges to reliable detection. …
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Analysis of Advanced Diversity Receivers for Fading Channels
… symbol error probability for a broad range of digital modulation schemes. A comprehensive study of various dual-diversity techniques with non-independent and non-identical fading statistics is also presented. Finally, the thesis develops some closed-form solutions for a few integrals involving …
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Digital Transmission by Hermite N-Dimensional Antipodal Scheme
A new N-dimensional digital modulation technique is proposed as a bandwidth efficient method for the transmission of digital data. The technique uses an antipodal scheme in which parallel binary data signs baseband orthogonal waveforms derived from Hermite polynomials. Orthogonality guarantees …
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Resource allocation for CDMA downlink to achieve maximum throughput
… varying one or more of the coding, interleaving, modulation and spreading block parameters. In the downlink of DS-CDMA systems, once the parameters of the above mentioned blocks are set, the base station will transmit at the lowest power level that can provide the QoS requirements of the service …
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Low computational complexity bit error rate simulation for personal communications systems in multipath and fading environments
… evaluating the performance of future wireless digital multiple access standards for fast and slow moving vehicles in outdoor environments. Code Division Multiple Access (CDMA) and Time Division Multiple Access (TDMA) are both multiple access techniques for wireless systems that can support …
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