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 41 for “"Local oscillator"”.
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Enhanced squeezing in homodyne detection via local-oscillator optimization
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.
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Practical Continuous Variable Quantum Key Distribution System with ‘Local’ Local Oscillator
… However, the requirement of a co-transmitted local oscillator (LO) brings a number of issues that compromises secure key generation and becomes a major obstacle to the practical implementation of CVQKD. To overcome these problems, a new CVQKD protocol with a locally generated LO (LLO) at Bob …
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A dual detector optical heterodyne receiver for local oscillator noise suppression
Thesis (Elec. E.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1985.
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Limitations and Improvement of Subcarrier Multiplexed Systems over Optical Fiber
… photodetector. Using a modified optical local oscillator to coherently detect the subcarrier channel this power fading can be eliminated. An optical local oscillator is centered at the optical carrier in order to perform homodyne detection. However, the local oscillator is modulated by a …
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Ultra low power, high sensitivity secure wake-up receiver for the Internet of Things
… architecture along with a low power free-running oscillator. The system is designed to be highly programmable in order to track the local oscillator frequency variations through a cascade of reconfigurable filters along the receiver chain. While the whole system is optimized to be duty cycled in a …
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Extensions of the Capabilities of a Balle-Flygare Microwave Spectrometer
… a low noise synthesizer as a source for the Local Oscillator (LO) signal, and by generating the Master Oscillator (MO) signal from the LO, with a single sideband mixer.
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Complete Temporal Characterization of Single Photons
… from a balanced homodyne detector at multiple local oscillator frequencies. We lay the theoretical foundation for our work and describe the experimental methods involved in detail. We show the results of testing our method on single photons heralded from bi-photons generated via four-wave …
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Influence of the Number of Degrees of Freedom on the Capacity of Incoherent Optical Fiber Communication Systems
… case of a coherent receiver, a strong optical local oscillator (in phase and with same polarization as the signal) is added to the signal prior to the photodetector. This results in the removal of the quadrature phase and polarization components, and reduces to the one degree of freedom (DOF) …
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CMOS bulk-driven mixers with passive baluns
… presented. Applying either the RF signal or the local oscillator (LO) signal to the bulk connection of the transistors allows the amplification and switching stages of a conventional mixer to be combined into a single stage, thus improving the voltage headroom of the mixer. The addition of a …
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Dissertation review on a new control perspective on phase locked loops
… locks the adjustable frequency of a local oscillator in reference to the incoming signal. However, the classic PLL technique has reviewed its first sign of weakness, limited convergence performance and complex in structure implementation. To overcome these weaknesses and to improve …
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Circuit Design And Reliability Of A Cmos Receiver
… noise amplifier (LNA). Except for band filters, local oscillators, and analog-digital converters which are usually implemented by COTS SAW filters and ICs, all the remaining blocks such as switch, LNA, mixer, and local oscillator are designed in MOSIS TSMC 0.35[micro]m technology in one chip. …
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An energy-efficient wireless data link for implantable electronics
… Since this technique only requires a single local oscillator (LO) in the external transceiver, the energy expenditure of the implanted transceiver is minimized. Simulated uplink data transfer rates of up to 10 Mbps has been shown. A PWM based ASK coding strategy was used for the downlink …
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Terahertz beam-steering imager using a scalable 2D-coupled architecture and multi- functional heterodyne pixels
… performs voltage-controlled 140 GHz local oscillation, 280-GHz-signal receiving, sub-harmonic mixing, and intermediate frequency (IF) signal extraction. Each pixel consumes 10 mW power and achieves a sensitivity of 2.9 pW in simulation. The local oscillator (LO) of the pixel is phase …
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Design and implementation of a X-band transmitter and frequency distribution unit for a synthetic aperture radar
… adverse weather conditions or darkness. A local consortium was established to demonstrate a consolidated South African SAR ability to demonstrate to the local and international communities, by generating high quality images with a South African X-band demonstrator. This dissertation forms …
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High-precision optical and microwave signal synthesis and distribution
… to the timing lock, phase synchronization to a local oscillator with subfemtosecond accuracy (<0.5 fs) over 1000 s is achieved. Drift-free subfemtosecond timing and phase synchronization enables a phase-coherent spectrum over 1.5 octaves that has a potential to generate single-cycle optical …
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Spontaneous brillouin scattering quench diagnostics for large superconducting magnets
… laser with very low noise as a frequency shifted local oscillator, the frequency shift of spontaneous Brillouin scattered light was measured using heterodyne detection. A pulsed laser was used to probe the fiber using Optical Time Domain Reflectometry (OTDR) to define the spatial resolution. The …
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Longer Range Backscatter Communications for IoT
… a spatially separated structure using a common local oscillator is also demonstrated. This approach allows for a potential range increase of up to 50 times. 2. A delay matching block using interpolation methods is developed for optimum range correlation that maximise phase noise suppression. …
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Two-Color interferometry as a fluctuation diagnostic on Alcator C-Mod
… CO2 laser chords are demodulated relative to a local oscillator using high bandwidth analog in-phase/quadrature electronics, replacing lower bandwidth digital fringe counting electronics. The raw outputs of the high bandwidth electronics, which are proportional to the sine and cosine of the …
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New strategies for low noise, agile PLL frequency synthesis
… employed in wireless communication systems for local oscillator generation. The ultimate goal in any design of frequency synthesisers is to generate precise and stable output frequencies with fast switching and minimal spurious and phase noise. The conflict between high resolution and fast …
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Homodyne High-harmonic Spectroscopy: Coherent Imaging of a Unimolecular Chemical Reaction
… from unexcited molecules acting as the reference local oscillator. First, applying time-resolved high-harmonic spectroscopy to the photodissociation of a diatomic molecule, Br2 to Br + Br, allows us to follow the break of a chemical bond occurring in a few hundreds of femtoseconds. Second, …
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