AffiliationBeijing Research Institute of Telemetry
Pulse Truncation Detector
Standard OQPSK Detector
Modified OQPSK Detector
MetadataShow full item record
RightsCopyright © held by the author; distribution rights International Foundation for Telemetering
Collection InformationProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection.
AbstractSOQPSK-TG is a highly bandwidth-efficient constant-envelope modulation so that it has been applied in airspace telemetry widely. We compare four types of coherent detectors for SOQPSK-TG, which are optimal detector, pulse truncation (PT) detector, standard OQPSK detector and modified OQPSK detector. The simulation and analysis results indicate that PT detector has the advantages of low complexity and good performance, so it has more practicality value.
SponsorsInternational Foundation for Telemetering
Showing items related by title, author, creator and subject.
Noise-limited performance of a hybrid detector and high-resolution display monitors.Browne, Michael Patrick. (The University of Arizona., 1991)In this dissertation I describe the analysis of two types of electronic devices. The first is an image intensifier/photomultiplier combination used in a laser communications receiver. The second type is high resolution display monitors to be used in digital radiology. The analysis of these devices centered on the influence of noise on their performance though I also measured other device characteristics. I present here a method of characterizing noise that can be used for a variety of detector and display devices; however, I concentrated my analysis on an optical communication receiver by ITT and high resolution display monitors by MegaScan, Tektronix and US Pixel. The optical receiver is called a hybrid device because it combines an image intensifier (II) and a photomultiplier tube. The II has a large active area and its specially processed photocathode gives it an extended red response. The photomultiplier tube (PMT) provides a high gain, low noise and low dark current. The hybrid tube had a maximum gain of 8 x 10⁶, a noise factor of 1.64 and an information capacity of 1.3 x 10⁶ bits per second. The high resolution monitors we examined were black and white monitors with a pixel matrix of at least 1024 x 1536 pixels and 256 grey levels. The maximum luminance from the monitors was 88 ft-Lamberts (for the US Pixel monitor) and a maximum information capacity of 8.9 x 10⁶ bits (for the MegaScan monitor). We measured spatial and temporal noise for the monitors. Spatial noise was the dominant noise, except at low grey levels. Veiling glare was evident in all three monitors and dramatically reduced the dynamic ranges of the monitors.
A Physical Model-based Correction for Charge Traps in the Hubble Space Telescope’s Wide Field Camera 3 Near-IR Detector and Its Applications to Transiting Exoplanets and Brown DwarfsZhou, Yifan; Apai, Dániel; Lew, Ben W. P.; Schneider, Glenn; Univ Arizona, Dept Astron, Steward Observ; Univ Arizona, Dept Planetary Sci, Lunar & Planetary Lab (IOP PUBLISHING LTD, 2017-05-04)The Hubble Space Telescope Wide Field Camera 3 (WFC3) near-IR channel is extensively used in time-resolved observations, especially for transiting exoplanet spectroscopy as well as. brown dwarf and directly imaged exoplanet rotational phase mapping. The ramp effect is the dominant source of systematics in the WFC3 for time-resolved observations, which limits its photometric precision. Current mitigation strategies are based on empirical fits and require additional orbits to help the telescope reach a thermal equilibrium. We show that the ramp-effect profiles can be explained and corrected with high fidelity using charge trapping theories. We also present a model for this process that can be used to predict and to correct charge trap systematics. Our model is based on a very small number of parameters that are intrinsic to the detector. We find that these parameters are very stable between the different data sets, and we provide best-fit values. Our model is tested with more than 120 orbits (similar to 40 visits) of WFC3 observations. and is proved to be able to provide near photon noise limited corrections for observations made with both staring and scanning modes of transiting exoplanets as well as for starting-mode observations of brown dwarfs. After our model correction, the light curve of the first orbit in each visit has the same photometric precision as subsequent orbits, so data from the first orbit no longer need. to. be discarded. Near-IR arrays with the same physical characteristics (e.g., JWST/NIRCam) may also benefit from the extension of this model if similar systematic profiles are observed.
Estimation methods for semiconductor gamma-ray detectorsMarks, Daniel George (The University of Arizona., 2000)Gamma-ray detectors based on high-density semiconductors, such as cadmium zinc telluride, are being developed for applications in nuclear medicine, astronomy and the monitoring of nuclear weapons material. In contrast to the more commonly used scintillators, which convert gamma-ray energy into light, semiconductors directly convert the energy of a gamma ray into electrical current. This direct conversion often leads to the perception that gamma-ray detection in semiconductors is not an estimation problem. This dissertation presents the contrasting view that gamma-ray detection in semiconductors is fundamentally an estimation problem, and it is only through the appropriate analysis of gamma-ray signals that optimal energy resolution and spatial resolution can be achieved. To estimate interaction parameters, such as the energy of the gamma ray and its interaction position, it is first necessary to have an accurate model of the detector system. In this work, the system consists of slabs of CdZnTe with arrays of pixel electrodes mounted on integrated readout circuits. A theoretical model of detector behavior is presented, including a new model for charge spreading in the detector. Methods for experimentally determining detector behavior are developed based on mapping detectors with narrow beams of gamma rays. Estimating the interaction positions and energies proceeds from a statistical model of the production of pixel signals, derived from our physical model. Energies and interaction positions are estimated by maximizing the likelihood function. The likelihood is the probability that a gamma ray with a given position and energy will produce an observed set of pixel signals. This maximum-likelihood estimation improves the energy resolution over simpler methods and can give the interaction position in three dimensions. A likelihood function can be calculated for an entire set of gamma rays, in which case an image can be estimated from the raw data without ever estimating individual interaction positions and energies. The Expectation-Maximization algorithm is used to reconstruct images and energy spectra by maximizing the ensemble likelihood function. In this work, the list-mode form of the algorithm is used, meaning that the raw data consist of lists of pixel signals for each gamma ray. Both spatial and energy resolution improve when this algorithm is applied to the raw pixel signals.