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 115 for “"Phase Modulation"”.
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Decoding algorithms for continuous phase modulation
Continuous Phase Modulation (CPM) possesses characteristics that make it very attractive for many applications. Efficient non-linear power amplifiers can be used in the transmitters of constant envelope CPM schemes. CPM also allows for the use of simple limiters in the demodulator rather than …
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All-optical processing using cross-phase modulation
… can occur such as timing jitter and phase wander. Traditionally these timing problems would have been corrected by converting the optical signal into the electrical domain and then compensating for the timing irregularity before converting the signal back into the optical domain. …
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Flexo electro-optic Liquid Crystals for Phase Modulation
… 3D photonic structures such as blue phase liquid crystals have of great interest to the displays industry and are highly desirable as spatial light modulators because of their polarisation independence and fast switching. However, these types of devices suffer from multistep …
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Reduced Complexity Detection Methods for Continuous Phase Modulation
Continuous phase modulation (CPM) is often plagued by high receiver complexity. One successful method of dealing with this is the well-known pulse amplitude modulation (PAM) representation of CPM, which was first proposed by Laurent. It is shown that the PAM representation also applies to multi-h …
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A likelihood ratio analysis of digital phase modulation
… to the problem of designing good trellis-coded modulation (TOM) schemes. The remarkably simple optimal receiver of minimum shift keying (MSK) has been shown to result from the mathematical simplification of its likelihood ratio into a single term. The log-likelihood ratio then becomes a linear …
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All-optical 2r regenerator based on self-phase modulation
… 2R Regeneration which is based on self-phase modulation (SPM) in a single highly nonlinear fiber (HNLF) with 2500 km length of transmission is investigated. In addition, there are two types of modulation format namely, non-return�to-zero on-off keying (NRZ-OOK) and return-to-zero on-off …
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Femtosecond Pulse Compression via Self-Phase Modulation in 1-Decanol
… generated using spectral broadening via self-phase modulation, followed by dispersion compensation. The most common spectral broadening technique exploits the nonlinear interaction of intense pulses focused into gas-filled hollow-core fibres. More recently, multiple crystal plates have been …
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RF phase modulation of optical signals and optical/electrical signal processing
Analog RF phase modulation of optical signals has been a topic of interest for many years, mainly focusing on Intensity Modulation Direct Detection (IMDD). The virtues of coherent detection combined with the advantages of Frequency Modulation, however, have not been explored thoroughly. By …
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High-order compensation of self-phase modulation in laser communication systems
Self-phase modulation (SPM) creates a power and fiber-length dependent spectral broadening that reduces signal-to-noise ratio in free-space laser communication systems which use a fiber to connect their transmitter's high-power optical amplifier to its telescope optics. The effects of SPM can be …
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High dimensionality carrierless amplitude phase modulation technique for radio over fiber system
Advanced modulation formats such as carrierless amplitude phase (CAP) modulation technique is one of the solutions to increase flexibility and high bit rates to support multi-level and multi-dimensional modulations with the absence of sinusoidal carrier. Recent work are focussing on the 2D CAP-64 …
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Enhance of LCOS Phase Modulation in Visible Wavelength Range Based on Metasurface
… on silicon (LCOS) technology to enhance the phase modulation capability while reducing the thickness of the liquid crystal layer, addressing key challenges in high-performance holographic displays. LCOS devices are known for their high-resolution light modulation, but their phase depth and …
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Electrically Tunable Liquid Crystal–Metasurface Devices for Phase Modulation in Telecom Band
Phase modulation of light is essential for reconfigurable photonic applications like display and optical communication. In liquid crystal on silicon (LCoS) devices, it is achieved by tuning the effective refractive index of the liquid crystal (LC) material. However, realising a full 2π shift …
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Amplitude and phase modulation techniques for an asymmetric multi-level outphasing transmitter
… the power supply switching network and the phase modulator. Both are ubiquitous building blocks in modern RF transceivers, and both are especially critical in Asymmetric Multilevel Outphasing (AMO) systems. A design of the power supply network and control scheme is proposed for an …
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8-Port Homodyne Detection of EIT-enhanced Cross-phase Modulation Using Broadband Signal Pulses
… processing. I have designed and implemented a phase-sensitive detection scheme for optical-frequency electromagnetic fields, which has been used to measure μrad phase shifts on nanosecond timescales. This phase measurement was developed for the express purpose of detecting cross-phase …
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Improvement of Fiber Optic System Performance by Synchronous Phase Modulation and Filtering at the Transmitter
… of a novel variant of a return-to-zero (RZ) modulation format, based on square-wave phase modulation and filtering of a continuous-wave (CW) signal, is investigated and compared with various modulation formats considered in the literature. We call this modulation format continuous-wave …
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Construction and characterization of a universally tunable modulator
Arbitrary admixtures of amplitude and phase modulated light can be used to generate linear, null-crossing error signals for locking Fabry-Perot cavities that are detuned from resonance by arbitrary amounts. Unfortunately, no commercially available device is capable of producing the desired …
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Development of a Method for Analysis and Incorporation of Rotorcraft Fluctuation in Synthesized Flyover Noise
… indefinitely, models for the amplitude and phase modulation must be developed. A band-limited random process will be explored for both the amplitude and phase modulations. An overlap-add technique, as well as a randomization technique and a modified phase modulation signal, defined as the …
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Characterising nonlinear waveguides by scanning near-field optical microscopy
… the interference of various modes with different phase modulation owing to dispersion and nonlinear effects. Accordingly, the complexity of the spectral features increase with the propagation distance and the number of contributing modes. The multimode spectra rapidly broaden at the beginning …
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Quantum Transport Experiments with Ultracold Atoms
… rotor investigations focus on the effects of phase modulation. By applying a periodic phase modulation of f0; 2 =3; 0g, the phase space is modified to generate a Hamiltonian ratchet, manifesting as directed transport within the chaotic sea without any biased force. We characterise the phase …
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