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SPECTRAL EFFICIENCY OF 8-ARY PSK MODULATION UTILIZING SQUARE ROOT RAISED COSINE FILTERINGScheidt, Kelly J. 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / As frequency allocation restrictions are tightening, and data rates are increasing, it is becoming
necessary to incorporate higher order modulation techniques to make more efficient use of available
spectrum. When used with Square Root Raised Cosine filtering, 8-ary Phase Shift Keyed
modulation is a spectrally efficient technique that makes better use of today’s RF spectrum in
comparison to standard formats. This paper will discuss 8-ary PSK modulation and its spectral
efficiency with a SRRC filter, along with comparisons to BPSK, QPSK, and FSK.
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PULSE SHAPED CONSTANT ENVELOPE 8-PSK MODULATION STUDYTao, Jianping 10 1900 (has links)
International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The most bandwidth-efficient communication methods are imperative to cope with the congested frequency bands. Pulse Shaping methods have excellent effects on narrowing bandwidth and increasing band utilization. The position of the baseband filters for the pulse shaping is crucial. Filters after the modulator will have non-constant envelope and before the modulator will have constant envelope. These two types have different effects on narrowing the bandwidth and producing bit errors. The constant envelope 8 PSK is used throughout the simulations and is compared with the non-constant envelope results. This work provides simulation results of spectrum analysis and measure of bit errors produced by pulse shaping in an AWGN channel.
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[en] A PERFORMANCE ANALYSIS OF PSK SYSTEMS WITH SEVERAL CARRIERS SHARING A CAMMON LINEAR CHANNEL / [pt] ANÁLISE DE DESEMPENHO DE SISTEMAS PSK COM MÚLTIPLAS PORTADORAS COMPARTILHANDO UM MESMO CANAL NÃO LINEARRAFAEL CIRIGLIANO SAMPAIO NETO 07 May 2007 (has links)
[pt] A análise de desempenho de sistemas de comunicações nos
quais um grande número de portadoras, de diferentes tipos
e níveis de potência, acessam uma mesma não-linearidade,
esbarra, inicialmente, na dificuldade de se determinar,
com precisão e tempo de computação aceitável, a
distribuição de potência do ruído de intermodulação
gerado. O problema torna-se ainda mais complexo nos casos
em que as portadoras têm envoltória variável no tempo,
quando, além de se tornar mais difícil a determinação do
espectro de intermodulção, há o aparecimento adicional da
transferência de modulação das demais portadoras para a
portadora desejada.
Com o enfoque voltado para o desempenho de sistemas
digitais, mostra-se que, utilizando-se determinados
algoritmos e aproximações, o tratamento analítico torna-se
factível. Com base na teoria apresentada, foi desenvolvido
um programa de computador que permite avaliação de
desempenho em situações bastante gerais. / [en] One of the difficulties arising in a theoretical
performance evaluation of communication systems in which
several carriers of various types are transmitted through
a cammon nonlinear amplifier, is related to the problem of
calculating, with good precision and within reasonable
computer time, the power spectrum of the intermodulation
noise generated at the output of the nonlinear device. The
analysis becomes more complex when the carriers have time-
varyng envelopes, since in such situations, besides the
difficulty involved in determining the power and spectrum
shape of the output signals and intermodulation products,
an extra system impairment should be taken into account.
Namely, the performance degradation due to modulation
transfer from all the other carriers into the desired
carrier.
With focus on digital systems, it is shoun that, by using
certain algorithms and approximations, theoretical
performance analysis is feasible. Based on the results
presented, a computer program was developed to evaluate
performance in fairly general situations.
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Studium vlivů frekvenčních nestabilit oscilátorů v družicových komunikačních systémech / Studies of Influences of Oscillators Frequency Instabilities in Satellite Communication SystemsBaran, Ondřej January 2011 (has links)
The dissertation thesis deals with a study of an influence of a simultaneous incidence of an additive thermal noise and a multiplicative phase noise on the useful signal transmission in narrowband satellite communication systems. While the additive thermal noise affects the useful signal only on the receiver side of the communication system, the multiplicative phase noise is produced in all system oscillators. One investigates how the receiver filter bandwidth reduction takes effect on the influence of individual noise types. The thesis is divided into four units. The first one (chapters 4 and 5) solves the ways of modeling of both noise types. In the second part (chapter 6), on the simple example, the primary analysis of the phase noise influence is made. Basic modulation schemes used in the satellite communication are also discussed (chapter 7). Third part (chapter 8) is devoted to the modeling of a general digital system with a M PSK modulation made directly on the main carrier wave. The last part (chapter 9) describes the modeling of a digital system with a BPSK modulation on the auxiliary subcarrier wave followed by an SSB modulation on the main carrier wave. General conclusions are deduced from obtained simulation results.
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