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 17 of 17 for “"Time modulation"”.
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Investigation of the pulse time modulation techniques for transmission of wideband signals
The choice of the modulation format is the principle factor in realising a highperformance bandwidth efficient communication system at an acceptable cost and complexity. Pulse time modulation technique represents an attractive alternative to purely digital or purely analogue modulation schemes …
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Low-power Power Management Circuit Design for Small Scale Energy Harvesting Using Piezoelectric Cantilevers
… mode (DCM) flyback converter, (ii) constant on-time modulation, and (iii) control of the clock frequency of a microcontroller unit (MCU). The DCM flyback converter behaves as a lossless resistor to match the source impedance for maximum power point tracking (MPPT). The constant on-time …
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Nonlinear flexural-flexural-torsional dynamics of metallic and composite beams
… equations describing the slow-time modulation of the amplitudes and phases of the interacting modes in the presence of one-to-one and/or two-to-one internal resonances. The inversion symmetry, D, symmetry, and 0(2) symmetry of the system are studied using the modulation …
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Modeling and Design of Digitially Controlled Voltage Regulator Modules
… silicon area. Single phase digital constant on-time modulation method is another good candidate to improve the DPWM resolution without adding too much cost. However, directly extending this method to multi-phase application, which is the prevalent structure in VRMs application, will introduce …
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Investigation of novel electroactive morphing concepts for aerodynamic performance increase of an A320 wing through High-Fidelity numerical simulation
… was performed with regard to a constant and time-modulation (“wobulation”) of the vibration frequency, enabling the detection of optimal morphing parameters. The actuation amplitude variation was investigated in the form of a sinusoidal spanwise travelling wave (STW) for different frequencies …
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Nonlinear and Time-Modulated Metamaterials: Applications at Microwave Frequencies
… properties, invoking nonlinear elements and/or time-modulating some of the material parameters, linearity and/or time-invariance can be broken in metamaterials, enabling extraordinary wave phenomena that open opportunities for the microwave engineering community, including the creation of …
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Wave transport in parity-time symmetric, time-varying, and quasi-periodic systems
… systems, in particular in the areas of parity-time symmetric systems, time-varying systems and quasi-periodic systems. These newly developed material platforms have been enabling many exotic wave-matter interaction phenomena unavailable in nature. In this context, I investigated a series of …
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Time-Modulated Array Testbed Prototype for Multibeam Spectrometry
… the development of a prototype testbed for real-time experimental studies of time-modulated arrays (TMAs). The design includes in-lab development of antenna elements, systems development of the heterodyne receiver architecture, and development of firmware and software for receiving and analyzing …
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Pressure, leakage and energy management in water distribution systems
A fast and efficient method to calculate time schedules for internal and boundary PRVs and flow modulation curves has been developed and implemented. Both time and flow modulation can be applied to a single inlet DMA. The time modulation methodology is based on solving a nonlinear programming …
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Coherent versus non-coherent space-time shift keying for co-located and distributed MIMO systems
In this thesis, we propose the novel Space-Time Coding (STC) concept of Space-Time Shift Keying (STSK) and explore its characteristics in the contexts of both co-located and cooperative Multiple-Input Multiple-Output (MIMO) systems using both coherent and non-coherent detection. Furthermore, we …
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Hybrid classical-quantum optimization algorithms in electromagnetic applications
… Guided by these insights, I introduce time-modulated simulated bifurcation (TM-SB), in which system parameters that are fixed in the classical formulation are deliberately modulated over time, together with a momentum-aware pumping strategy. This time modulation makes the dynamics much …
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Unraveling Molecular Mechanisms Regulating Dormancy and Bloom Time in Apple (Malus × domestica Borkh)
… chemical and/or genetic approaches for bloom-time modulation to avoid spring frost. Using two apple cultivars, 'Cripps Pink' and 'Honeycrisp,' representing early- and late-blooming cultivars, respectively, the present study specifically investigated the accumulation kinetics of plant hormones, …
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The potential of the superoxide dismutase inhibitor, diethyldithiocarbamate as an adjuvant to radiotherapy
… If inhibition of SOD by DOC increases the lifetime and effectiveness of radiation induced O₂⁻, it follows that the potential exists for DOC to enhance the effect of radiation. DOC is however also a thiol compound, and thus may act as a radioprotector by modifying tissue oxygenation status or by …
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Digital pulse interval modulation for optical communication systems
<p>Pulse time modulation (PTM) techniques have drawn considerable attention over the years as suitable schemes for transmission of information over optical fibres. PTM schemes are known to utilise the vast optical bandwidth to provide efficient transmission characteristics. Pulse code modulation is …
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Small-signal Analysis and Design of Constant-on-time V2 Control for Ceramic Caps
Recently, constant-on-time V2 control is more and more popular in industry products due to features of high light load efficiency, simple implementation and fast transient response. In many applications such as cell phone, camera, and other portable devices, low-ESR capacitors such as ceramic caps …
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Modeling and Stability Analysis for Multiphase Constant On-Time Control With Phase Overlapping
… multiphase current-mode and V² constant on-time (COT) control techniques are widely used because these control methods can help increase control bandwidth, minimize output impedance, and achieve fast transient response with less output capacitance. To supply large current demands, the phase …
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Equivalent Circuit Model for Current Mode Controls and Its Extensions
… control in the frequency domain. A continuous time domain model was recently proposed as a successful model for current-mode control architectures. However, the model was derived by describing function method, which is very arithmetically complicated, not to mention time consuming. For the …