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 103 for “"heterodyne"”.
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Broadband nanosensing using heterodyne interferometry
Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.
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Spatial tracking for optical heterodyne communication
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1984.
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Submillimeter heterodyne spectroscopy of star forming regions
… testing and deployment of two sub-mm wave heterodyne array receivers. Polestar is a 4 pixel (2 x 2) heterodyne array built for operation in the 810 GHz atmospheric window. It is in operation at the AST/RO telescope at the South Pole. This receiver has increased imaging speed in this band at …
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Atmospheric propagation effects on heterodyne-reception optical radars
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1982.
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Plasma Electron Density Measurement Using Homodyne and Heterodyne Interferometers
… different interferometer designs, homodyne and heterodyne are studied in two fusion reactor systems namely Tokamak and flow through Z-pinch device.
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Advanced optical calibration of the Herschel HIFI heterodyne spectrometer
The Heterodyne Instrument for the Far-Infrared (HIFI) was launched aboard the Herschel Space Observatory on the 14th of May 2009. HIFI's frequency range is spread over 7 mixer bands. Bands 1-5 (480-1270 GHz) use Superconducting-Insulator-Superconducting (SIS) mixer technology while bands 6 & 7 …
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Time-Offset Fractional-N PLLs for Heterodyne FMCW SAR
… fractional-N phase locked loops (PLLs) for heterodyne frequency-modulated continuous-wave (FMCW) synthetic aperture radar (SAR) and the impact of spurii on such a system. Heterodyne receiver architectures avoid phenomena which limit the sensitivity of their homodyne counterparts, and enable …
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The Development of A Spatial Heterodyne Spectrometer For Raman Spectroscopy
… for planetary applications called the Spatial Heterodyne Raman Spectrometer (SHRS). The SHRS is based on a Michelson interferometer, but the SHRS uses stationary diffraction gratings in place of mirrors and requires no moving parts. The SHRS does not require long focal length optics to achieve …
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Comparison of Direct and Heterodyne Detection Optical Intersatellite Communication Links
The performance of direct and heterodyne detection optical intersatellite communication links are evaluated and compared. It is shown that the performance of optical links is very sensitive to the pointing and tracking errors at the transmitter and receiver. In the presence of random pointing and …
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An integrated heterodyne interferometer with on-chip detectors and modulators
… In these applications, the preferred mode is the heterodyne interferometer. However, modern heterodyne interferometers are complex systems requiring bulk optical devices to be implemented. As a result, they are large and expensive precision instruments limited to industrial and scientific …
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Two-Color Heterodyne Interferometry for PI3 Line-Averaged Plasma Density Measurements
This thesis investigates two-color heterodyne interferometry, which is a technique used for plasma density diagnostics in fusion experiments. Funded through a Mitacs Accelerate internship, this work focused on improving vibration compensation of the existing multi-chord interferometer used at …
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Distributed fibre sensing using microwave heterodyne detection of spontaneous Brillouin backscatter
Brillouin scattering has been used for many years in optical fibre temperature and strain sensing applications, due to the dependence of both the power and the frequency shift of the scattered radiation on these two quantities. Simultaneous temperature and strain sensing is possible if both the …
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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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Optical measurement of neural action potentials using low coherence heterodyne interferometry
… low coherence interferometry. The dual beam heterodyne interferometer (DBHI) is a modified Michelson with a low coherence source and an optical referencing method capable of detecting sub-nanometer optical path changes. In this interferometer, acousto-optical modulators were used to produce …
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Decorrelation time of speckle targets observed with a heterodyne-reception optical radar
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1982.
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Phase-locking terahertz quantum cascade lasers for high dynamic range heterodyne imaging
… This can be achieved using a combination of heterodyne detection and a phase-locked loop to selectively lower the system noise floor while preserving signal power. In this thesis, an optical phase-locked loop using a Schottky diode mixer and 3rd order DFB QCLs is implemented to achieve a …
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Recommissioning REDDI: Reviving a Doppler Asymmetric Spatial Heterodyne Spectrometer for Observing Thermospheric Winds
… to prove that a Doppler Asymmetric Spatial Heterodyne (DASH) spectrometer could be used to accurately measure thermospheric winds by observing the Doppler shift of the 630nm emission of oxygen in the thermosphere. In 2015, we began a project to redesign the input optics of REDDI to repurpose …
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Investigation of chiral porphyrin aggregates with heterodyne-detected vibrational sum frequency generation spectroscopy
… prompting further, more detailed studies. Heterodyne-detected vibrational sum frequency generation (HD-VSFG) spectroscopy is a phase-sensitive, second-order nonlinear technique which probes the vibrational characteristics of noncentrosymmetric molecular environments. HD-VSFG experiments can …
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Characterization of coherence in forward-scattered photons in tubid medium using heterodyne detection
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.
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