Global ETD Search
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Showing 1 to 20 of 75 for “"QAM"”.
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Blind Synchronization and Detection of Nyquist Pulse Shaped QAM Signals
… pulse shaped quadratureamplitude modulation (QAM) signals. The focus is on single carrier signals. The blind receiver includes the estimation of the symbol rate, the roll-off factor of the filter, the optimal sample phase, the frequency offset, the phase offset and as well as the correction of …
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A hybrid-structure offset-QAM filter-bank multi-carrier MIMO system
Offset quadrature amplitude modulation (OQAM) filter-bank multi-carrier (FBMC), has great potential for boosting the spectral efficiency (SE) and energy efficiency (EE) of future communication systems. This is due to its superior spectral localization, CP-less transmission and relaxed …
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Low-jitter symbol timing recovery for M-ary QAM and PAM signals
… timing recovery schemes applicable to M-ary QAM and PAM signals. Franks and Bubrowski introduced highpass prefiltering and symmetric bandpass post-filtering for jitter-free operation of a symbol timing recovery scheme using a squarer for binary signaling. We show that the same conditions are …
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Classification and Parameter Estimation of Asynchronously Received PSK/QAM Modulated Signals in Flat-Fading Channels
… and noncoherent modulation classifier for PSK/QAM modulated signals in flat-fading channels. In developing this classifier, a novel estimator for the unknown channel gain and fractional time delay is proposed which uses a method-of-moments based estimation approach. For the second research …
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Error relilient video communications using high level M-QAM. Modelling and simulation of a comparative analysis of a dual-priority M-QAM transmission system for H.264/AVC video applications over band-limited and error-phone channels.
… 16, 64 and 256) Quadrature Amplitude Modulation (QAM) transmission system suitable for video transmission is presented. The communication system is based on layered video coding and unequal error protection to make the video bitstream robust to channel errors. An implementation is described in …
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Province-Wide Survey of the Effects of Quality Assurance Measures on Services for Adults with Intellectual/Developmental Disabilities and Challenging Behaviours
… that includes the Quality Assurance Measures (QAM) for Behaviour Interventions (Part III) and the QAM Policy Directives for adults with intellectual and developmental disabilities (IDD) and challenging behaviour. No research has examined the impact of QAM on IDD services. Methods: Online …
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Adaptive multilevel quadrature amplitude radio implementation in programmable logic
… methods like Quadrature Amplitude Modulation (QAM) to increase the channel efficiency and maximize data throughput. Unfortunately, the performance of high level QAM modulations in the wireless channel is sensitive to channel imperfections and throughput is degraded significantly at low …
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Quadrature amplitude modulated codes with low peak-to-mean envelope power ratio for orthogonal frequency division multiplexing applications
… properties of quadrature amplitude modulated (QAM) OFDM signals with low PMEPR, focusing in particular on signals based on 4-QAM and 16-QAM constellations. We construct and prove new code structures for sequences in 4-QAM and 16-QAM that result OFDM signals with low PMEPR. Many practical …
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Implications of Fiber Nonlinearities on Coherent Optical Fiber Communications
… 16-ary quadrature amplitude modulation (DP 16-QAM) systems are quantified in terms of SEP. The experimental results demonstrate that the launch power that minimizes the bit error ratio and SEP coincides. The research utilizes spectral and power efficient multi-dimensional modulation formats, …
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ΜΕΛΕΤΗ ΚΑΙ ΥΠΟΛΟΓΙΣΜΟΣ ΤΗΣ ΕΠΙΘΥΜΗΤΗΣ ΠΡΟΠΑΡΑΜΟΡΦΩΣΗΣ ΓΙΑ ΤΗΝ ΔΙΟΡΘΩΣΗ ΤΗΣ ΕΙΣΑΓΟΜΕΝΗΣ ΠΑΡΑΜΟΡΦΩΣΗΣ ΣΕ ΜΗ ΓΡΑΜΜΙΚΟΥΣ ΠΟΛΥΕΠΙΠΕΔΟΥΣ ΨΗΦΙ...
… USING M-ARY DIGITAL SCHEMES SUCH AS M-ARY QAM [1.4]. IN FACT M- ARYQAM SCHEMES PRESENT MUCH BETTER POWER/BANDWIDT EFFICIENCY THAN THE EQUIVALENT M-ARY PSK IN AWGN ENVIRONMENT. MOREOVER, COCHANNEL IMMUNITY OF M-ARY QAM IS SUPERIOR TO THAT OF M-ARY PSK BUT IN THE CONTRAST THEY ARE ESPECIALLY …
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Investigation of TQM implementation to the UAE public sector organisations.
… empirical evidences a Quality Appraisal Model (QAM) emerged as a self assessment instrument against the U.A.E. Government Excellence Program (UAEGEP) criteria's. The QAM comprises of four core quality critical factors: people, leadership, processes and system, and resources and facilities, in …
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On the Impact of Channel and Channel Quality Estimation on Adaptive Modulation
… schemes such as quadrature amplitude modulation (QAM) techniques. QAM yields the high spectral efficiency due to its use of amplitude as well as phase modulation and therefore is an effective technique for achieving high channel capacity. The main drawbacks of QAM modulation are its reduced energy …
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Characterization and Computation of Optimal Distributions for Channel Coding
… to outperform the currently widely used PSK and QAM schemes at all transmission rate below the channel capacity.
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Novel predistortion techniques for RF power amplifiers
… are applied to both two-tone tests and 16 QAM (Quadrature Amplitude Modulation) signals. The test power amplifiers vary from class A, inverse class E, to cascaded amplifier systems. Our experiments have demonstrated that these new predistortion techniques can reduce the upper and lower …
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Fast peak-power reduction for MIMO-OFDM systems with diversity
… dB and 2.08 dB of PAPR reduction for QPSK and 16-QAM original constellations, respectively, for 256 subcarriers. Results also show that 4.29 dB and 3.41 dB of PAR reduction are obtained for QPSK and 16-QAM original constellations, respectively, for 1024 subcarriers. Furthermore, we show how the …
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Analysis, improvement and extensions of a Lee metric list decoding algorithm for alternant codes
… codes over a Gaussian channel with a PSK or QAM modulation and to compare Lee and Hammming metrics.
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Experimental demonstration of cap transmitter using very high speed IC hardware description language (VHDL)
… scheme which it is strongly inspired by QAM modulation scheme. CAP does not depend on a carrier and it is much simpler. Lots of CAP modulation experiments have been proposed and demonstrate but none of them were introduced in real time system. Therefore Very High Speed IC Hardware …
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A FPGA/DSP based ultrasound system for tumor detection
… of Quadrature Amplitude Modulation (QAM) receiver on FPGA for received signal from ultrasound detector. LTP is applied to the tumor samples through the transmitter and the received signal at ultrasonic receiver is passed through QAM to get different maxima (peaks) which are then …
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Techniques for high-efficiency outphasing power amplifiers
… than the standard outphasing system for a 16-QAM signal. The second technique to improve the efficiency of the outphasing system is asymmetric multilevel outphasing (AMO) modulation. In the AMO system, the amplitude for each of the two outphased PAs can switch independently among multiple …
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