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 56 for “"QPSK"”.
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Radio frequency direct-digital QPSK modulators in CMOS technology
… direct-digital Quadrature Phase Shift Keying (QPSK) modulators are proposed in low-cost Complimentary Metal Oxide Semiconductor (CMOS) technology for radio frequency (RF) wireless applications. Direct-digital architectures have attracted much attention recently as they potentially offer …
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Towards integrated QPSK transceiver on zero-change CMOS foundry process
… scheme, such as quadrature phase-shift keying (QPSK), is a possible solution. Another limitation is energy consumption. Power density within telecommunication data centers are regulated by law in consideration of ambient temperature and noise level. Therefore, optical transceivers with higher …
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Ambient ZeroScatter: Ambient BPSK and QPSK Backscatter Communication using Existing Digital I/O Pins
… to produce quadrature phase-shift keying (QPSK) backscatter modulation. We additionally demonstrate a complete ambient backscatter communication system, consisting of the BPSK ZeroScatter tag, dipole antennas, and a direct sampling digital receiver. With an input clock frequency of 2.9 …
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Design, Implementation and Assessment of BPSK and QPSK PAPR over OFDM signals using LimeSDR
… Keying (BPSK) or Quadrature Phase Shift Keying (QPSK), which then brought in the question “What was their contribution to Peak-to-Average Power Ratio (PAPR) in an OFDM system?”. Consequently, this project compared BPSK and QPSK in terms of PAPR in OFDM signals. A personal computer was used to …
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Μελέτη αλγορίθμων ψηφιακής επεξεργασίας σήματος για ομόδυνο δέκτη QPSK σε οπτικά συστήματα μεγάλων αποστάσεων υψηλής φασματικής απόδοσης
… is placed on quadrature phase-shift keying (QPSK), and specifically on polarization division multiplexed (PDM) QPSK. A special kind of receiver is investigated thoroughly, the digital coherent receiver, the equivalent of the coherent quadrature demodulator in classical communications …
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Cascaded ROADM Filter Replication and the Effects of Statistical Variations in the Response of Cascaded ROADMs on 100 Gb/s DP-QPSK System Performance
… using a WaveLogic 3 real-time transceiver in QPSK mode. In this setting, the transceiver sends and receives a QPSK signal, performing all of its digital signal processing in real-time. Similar to the filter replication section, the real-time performance of the WL3 transceiver was tested with …
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An investigation into the performance of a power-of-two coefficient transversal equalizer in a 34Mbit/s QPSK digital radio during frequency-selective fading conditions
… An adaptive equalizer located in a 34MBit/s QPSK digital radio is required to operate at very high speed, and its digital hardware implementation is not a trivial task. In order to reduce the cost and complexity, a compromise was proposed. If the tap weights of the equalizer could be …
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Space-Time Coding with Offset Modulations
… that the telemetry versions of Feher-patented QPSK (FQPSK-JR) and shaped offset QPSK (SOQPSK-TG) can be interpreted as both cross-correlated, trellis-coded quadrature modulation (XTCQM) and continuous phase modulation (CPM). Based on these representations, both modulations can be detected with …
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Energy-Efficient Multicarrier and Multicarrier-CDMA Systems
… Keying (BPSK), Quadrature Phase Shift Keying (QPSK), and -QPSK are obtained as a function of number of subcarriers in the system. It is shown that PAPR reductions up to can be achieved using the proposed methods for a 128-subcarrier OFDM system. These reductions amount to increased energy …
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Optické koherentní přenosové systémy
… simulací koherentní optické sítě s využitím PM-QPSK a PM-16QAM modulace pro šířku pásma 112 Gbit/s a 224 Gbit/s
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Space-time block coding with imperfect channel estimates
… fading when using Quadrature Phase Shift Keying (QPSK) at a bit error rate of 10 -3. In this thesis, the performance of space-time block codes is analyzed when the receiver must rely on noisy, or imperfect, estimates of the channel. It is shown that for a QPSK signal constellation the system is …
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Optimising Signal Isolation and Phase Measurement in Digitally Enhanced Interferometry
… a four-level Quadrature Phase Shift Keying (QPSK) code generated from two m-sequences, which compromises the code autocorrelation. This degrades signal isolation and increases crosstalk. To improve DEHoI autocorrelation, we develop a hybrid QPSK code using a single m-sequence and a square …
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Optimising Signal Isolation and Phase Measurement in Digitally Enhanced Interferometry
… a four-level Quadrature Phase Shift Keying (QPSK) code generated from two m-sequences, which compromises the code autocorrelation. This degrades signal isolation and increases crosstalk. To improve DEHoI autocorrelation, we develop a hybrid QPSK code using a single m-sequence and a square …
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Fast peak-power reduction for MIMO-OFDM systems with diversity
… PAPR reduction gains of 4.19 and 3.57 dB under QPSK for Alamouti STBC and SFBC, respectively. In addition, we extend the e cient ACE-SGP method to rotated constellations for SISO-OFDM systems, an alternative method recently invented for providing diversity. Simulation results show approximately …
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Adaptive polarization mode dispersion equalizers for coherent optical communications systems
… multiplexed (PDM) quadrature phase-shift keying (QPSK) systems in all order PMD emulation model. In the exclusive presence of PMD, we demonstrated that the half-symbol-period-spaced adaptive electronic equalizers, based on the constant modulus algorithm (CMA) equalizers perform slightly better …
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Overloaded Array Processing with Spatially Reduced Search Joint Detection
… over 2M zero excess bandwidth synchronous QPSK signals with an M element array. Also, this thesis investigates a temporal processing technique similar to SRSJD, Temporally Reduced Search Joint Detection (TRSJD), that separates co-channel, asynchronous, partial response signals. The …
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Efficiency Improvement of WCDMA Base Station Transmitters using Class-F power amplifiers
… schemes such as Quadrature Phase Shift Keying (QPSK). But modulation schemes such as QPSK need, in turn, a very linear power from the output of the transmitter power amplifier in order to meet the spectral requirements. A linear power amplifier, traditionally, has very low energy efficiency. …
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Analysis of digital communication signals and extraction of parameters
… Keying (BPSK), Quadrature Phase Shift Keying (QPSK), Frequency Shift Keying (FSK), and On-Off Keying (00K). The analysis emphasizes the use of available signal processing software. Detection methods compared include broadband energy detection, FFT- based narrowband energy detection, and two …
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Equalization Techniques For Multipath Mitigation in Aeronautical Telemetry
… (DF-MMSE) concept to the two compatible offset QPSK waveforms (FQPSK and SOQPSK-TG) that constitute the ARTM Tier-1 waveforms. An adaptive version of the DF-MMSE equalizer is developed and applied to this application. In the presence of frequency selective multipath interference typically …
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