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- Heterojunctions (7)
- Decoding (3)
- Error statistics (3)
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- MODFETs (3)
- Multiple quantum wells (3)
- Remote sensing by radar (3)
- Backscatter (2)
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- Hall mobility (2)
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- Phase shift keying (2)
- Photoluminescence (2)
- Quadrature amplitude modulation (2)
- Radar cross-sections (2)
- Radiometry (2)
- Spaceborne radar (2)
- AWGN channels (1)
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- Atmospheric measuring apparatus (1)
- Atmospheric techniques (1)
- Band gap (1)
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Articles 1 - 26 of 26
Full-Text Articles in Engineering
High-Quality P-N Junctions With Quaternary Alingan/Ingan Quantum Wells, A. Chitnis, A. Kumar, M. Shatalov, V. Adivarahan, A. Lunev, J. W. Yang, Grigory Simin, M. Asif Khan, R. Gaska, M. Shur
High-Quality P-N Junctions With Quaternary Alingan/Ingan Quantum Wells, A. Chitnis, A. Kumar, M. Shatalov, V. Adivarahan, A. Lunev, J. W. Yang, Grigory Simin, M. Asif Khan, R. Gaska, M. Shur
Faculty Publications
We report on quaternary AlInGaN/InGaN multiple quantum well(MQW)light emitting diode structures grown on sapphire substrates. The structures demonstrate high quality of the p–njunctions with quaternary MQW. At low forward bias (below 2 V), the temperature dependent of current–voltage characteristics are exponential with the ideality factor of 2.28, which is in a good agreement with the model of the injected carrier recombination in the space charge region. This ideality factor value is approximately three times lower than for conventional GaN/InGaN light emitting diodes(LEDs). The obtained data indicate the recombination in p–njunction space charge region to be responsible for a current transport …
Finite-Aperture Wire Grid Polarizers, Michael A. Jensen, Gregory P. Nordin
Finite-Aperture Wire Grid Polarizers, Michael A. Jensen, Gregory P. Nordin
Faculty Publications
The transmission characteristics of wire grid polarizers fabricated in finite apertures are investigated by using a three-dimensional finite-difference time-domain formulation. Specifically, the optical transmissivity and extinction ratio are characterized for a wide variety of geometrical parameters including aperture size in both dimensions, conducting wire fill factor, and polarizer thickness. A dispersive material model is used to investigate the performance of polarizers fabricated by using realistic metals at infrared wavelengths. The results indicate that the aperture dimension significantly impacts the polarizer transmission behavior and that the extinction of the unwanted polarization is often limited by depolarizing scattering that is due to …
Direct Generation Of Optical Diffractive Elements In Perfluorocyclobutane (Pfcb) Polymers By Soft Lithography, Gregory P. Nordin, J. Ballato, P. C. Deguzman, S. Foulger, H. Shah, D. Smith
Direct Generation Of Optical Diffractive Elements In Perfluorocyclobutane (Pfcb) Polymers By Soft Lithography, Gregory P. Nordin, J. Ballato, P. C. Deguzman, S. Foulger, H. Shah, D. Smith
Faculty Publications
Optically diffractive line gratings with 0.58- m feature sizes have been generated in 100- m perfluorocyclobutane (PFCB) polymer films by direct micromolding using only a silicon master. Strong reflectivities from the green to red portions of the visible spectrum, depending on incident beam angle, were observed with 3 dB bandwidths of approximately 30 nm. This negative mold-free technique permits, for the first time to our knowledge, feature reproduction at submicrometer size scales, eliminates several steps from conventional soft lithographic methods, and marks itself as a practical means for rapidly generating planar photonic structures that operate spectrally in the visible and …
Effect Of Gate Leakage Current On Noise Properties Of Algan/Gan Field Effect Transistors, S. L. Rumyantsev, N. Pala, M. S. Shur, R. Gaska, M. E. Levinshtein, M. Asif Khan, Grigory Simin, X. Hu, J. Yang
Effect Of Gate Leakage Current On Noise Properties Of Algan/Gan Field Effect Transistors, S. L. Rumyantsev, N. Pala, M. S. Shur, R. Gaska, M. E. Levinshtein, M. Asif Khan, Grigory Simin, X. Hu, J. Yang
Faculty Publications
The effect of the gate leakage current fluctuations on noiseproperties of AlGaN/GaN heterostructurefield effect transistors(HFETs) has been studied in conventional HFET structures and in AlGaN/GaN metal-oxide-semiconductorheterostructurefield effect transistors (MOS-HFETs). The comparison of the noiseproperties of conventional AlGaN/GaN HFETs and AlGaN/GaN MOS-HFETs fabricated on the same wafer, allowed us to estimate the contribution of the gate currentnoise to the HFET’s output noise. The effect of the gate current fluctuations on output noiseproperties of HFETs depends on the level of noise in the AlGaN/GaN HFETs. For the transistors with a relatively high magnitude of the Hooge parameter α∼10−3, even a …
System Level Microwave Design: Radar-Based Laboratory Projects, Michael A. Jensen, David V. Arnold, Donald E. Crockett
System Level Microwave Design: Radar-Based Laboratory Projects, Michael A. Jensen, David V. Arnold, Donald E. Crockett
Faculty Publications
Two laboratory projects-a Doppler radar and a synthetic aperture radar (SAR)-designed to augment traditional electromagnetics education are proposed. The projects introduce students to component and system level design and expose them to modern computer-aided design (CAD) tools, microstrip and surface mount fabrication technologies, and industry standard test equipment and procedures. Additionally, because the projects result in a working radar system, students gain new enthusiasm for the electromagnetics discipline and directly see its relevance in the engineering field. Implementation of these laboratories within the curriculum have proven to be highly motivational and educational and have even contributed to increased enrolments in …
High Performance Micropane Electron Beam Window, Roger A. Dougal, Shengyi Liu
High Performance Micropane Electron Beam Window, Roger A. Dougal, Shengyi Liu
Faculty Publications
A silicon disk etched so that it contains a multitude of microscopic and thin window panes (micropanes) can potentially transmit a larger average electron beam current density and absorb a smaller fraction of the beam energy than a common metal foil window. The enhanced performance is achieved by a combination of decreased power loss due to the extremely small window thickness (~1 μm), and increased conductive cooling due to the small diameter (~50 μm) of the micropanes and the large cross section of the honeycomb structure that supports the micropanes. Beam current densities up to 34 A/cm2 are permitted within …
Enhanced Luminescence In Ingan Multiple Quantum Wells With Quaternary Alingan Barriers, Jianping Zhang, J. Yang, Grigory Simin, M. Shatalov, M. Asif Khan, M. S. Shur, R. Gaska
Enhanced Luminescence In Ingan Multiple Quantum Wells With Quaternary Alingan Barriers, Jianping Zhang, J. Yang, Grigory Simin, M. Shatalov, M. Asif Khan, M. S. Shur, R. Gaska
Faculty Publications
We report on the comparative photoluminescence studies of AlGaN/GaN, GaN/InGaN, and AlInGaN/InGaN multiple quantum well(MQW) structures. The study clearly shows the improvement in materials quality with the introduction of indium. Our results point out the localized state emission mechanism for GaN/InGaN structures and the quantum well emission mechanism for AlInGaN/InGaN structures. The introduction of indium is the dominant factor responsible for the observed differences in the photoluminescence spectra of these MQW structures.
High Electron Mobility In Algan/Gan Heterostructures Grown On Bulk Gan Substrates, E. Frayssinet, W. Knap, P. Lorenzini, N. Grandjean, J. Massies, C. Skierbiszewski, T. Suski, I. Grzegory, S. Porowski, Grigory Simin, X. Hu, M. Asif Khan, M. S. Shur, R. Gaska, D. Maude
High Electron Mobility In Algan/Gan Heterostructures Grown On Bulk Gan Substrates, E. Frayssinet, W. Knap, P. Lorenzini, N. Grandjean, J. Massies, C. Skierbiszewski, T. Suski, I. Grzegory, S. Porowski, Grigory Simin, X. Hu, M. Asif Khan, M. S. Shur, R. Gaska, D. Maude
Faculty Publications
Dislocation-free high-quality AlGaN/GaN heterostructures have been grown by molecular-beam epitaxy on semi-insulating bulk GaN substrates. Hall measurements performed in the 300 K–50 mK range show a low-temperature electron mobility exceeding 60 000 cm2/V s for an electron sheet density of 2.4×1012 cm−2. Magnetotransport experiments performed up to 15 T exhibit well-defined quantum Hall-effect features. The structures corresponding to the cyclotron and spin splitting were clearly resolved. From an analysis of the Shubnikov de Hass oscillations and the low-temperature mobility we found the quantum and transport scattering times to be 0.4 and 8.2 ps, respectively. The …
Optical Bandgap Formation In Alingan Alloys, G. Tamulaitis, K. Kazlauskas, S. Juršėnas, A. Žukauskas, M. A. Khan, J. W. Yang, J. Zhang, Grigory Simin, M. S. Shur, R. Gaska
Optical Bandgap Formation In Alingan Alloys, G. Tamulaitis, K. Kazlauskas, S. Juršėnas, A. Žukauskas, M. A. Khan, J. W. Yang, J. Zhang, Grigory Simin, M. S. Shur, R. Gaska
Faculty Publications
We report on the spectral dynamics of the reflectivity, site-selectively excited photoluminescence,photoluminescence excitation, and time-resolved luminescence in quaternary AlInGaN epitaxial layers grown on GaN templates. The incorporation of a few percents of In into AlGaN causes significant smoothening of the band-bottom potential profile in AlInGaN layers owing to improved crystal quality. An abrupt optical bandgap indicates that a nearly lattice-matched AlInGaN/GaN heterostructure with large energy band offsets can be grown for high-efficiency light-emitting devices.
Algan/Gan Metal-Oxide-Semiconductor Heterostructure Field-Effect Transistors On Sic Substrates, M. Asif Khan, X. Hu, A. Tarakji, Grigory Simin, J. Yang, R. Gaska, M. S. Shur
Algan/Gan Metal-Oxide-Semiconductor Heterostructure Field-Effect Transistors On Sic Substrates, M. Asif Khan, X. Hu, A. Tarakji, Grigory Simin, J. Yang, R. Gaska, M. S. Shur
Faculty Publications
We report on AlGaN/GaN metal–oxide–semiconductor heterostructurefield-effect transistors (MOS-HFETs) grown over insulating 4H–SiC substrates. We demonstrate that the dc and microwave performance of the MOS-HFETs is superior to that of conventional AlGaN/GaN HFETs, which points to the high quality of SiO2/AlGaNheterointerface. The MOS-HFETs could operate at positive gate biases as high as +10 V that doubles the channel current as compared to conventional AlGaN/GaN HFETs of a similar design. The gate leakage current was more than six orders of magnitude smaller than that for the conventional AlGaN/GaN HFETs. The MOS-HFETs exhibited stable operation at elevated temperatures up to 300 …
Sio2-Passivated Lateral-Geometry Gan Transparent Schottky-Barrier Detectors, V. Adivarahan, Grigory Simin, J. W. Yang, A. Lunev, M. Asif Khan, M. Pala, M. Shur, R. Gaska
Sio2-Passivated Lateral-Geometry Gan Transparent Schottky-Barrier Detectors, V. Adivarahan, Grigory Simin, J. W. Yang, A. Lunev, M. Asif Khan, M. Pala, M. Shur, R. Gaska
Faculty Publications
We report on a transparent Schottky-barrierultraviolet detector on GaN layers over sapphire substrates. Using SiO2 surface passivation, reverse leakage currents were reduced to a value as low as 1 pA at 5 V reverse bias for 200 μm diameter device. The device exhibits a high internal gain, about 50, at low forward biases. The response time (about 15 ns) is RC limited, even in the internal gain regime. A record low level of the noise spectral density, 5×10−23 A2/Hz, was measured at 10 Hz. We attribute this low noise level to the reduced reverse leakage current.
Azimuth Variation In Microwave Scatterometer And Radiometer Data Over Antarctica, David G. Long, Mark R. Drinkwater
Azimuth Variation In Microwave Scatterometer And Radiometer Data Over Antarctica, David G. Long, Mark R. Drinkwater
Faculty Publications
While designed for ocean observation, scatterometer and radiometer data have proven very useful in a variety of cryosphere studies. Over large regions of Antarctica, ice sheet and bedrock topography and the snow deposition, drift, and erosional environment combine to produce roughness on various scales. Roughness ranges from broad, basin-scale ice-sheet topography at 100 km wavelengths to large, spatially coherent dune fields at 10 km wavelength to erosional features on the meter scale known as sastrugi. These roughness scales influence the microwave backscattering and emission properties of the surface, combining to introduce azimuth-angle dependencies in the satellite observation data. In this …
Neural Networks Versus Nonparametric Neighbor-Based Classifiers For Semisupervised Classification Of Landsat Thematic Mapper Imagery, Perry J. Hardin
Neural Networks Versus Nonparametric Neighbor-Based Classifiers For Semisupervised Classification Of Landsat Thematic Mapper Imagery, Perry J. Hardin
Faculty Publications
Semisupervised classification is one approach to converting multiband optical and infrared imagery into landcover maps. First, a sample of image pixels is extracted and clustered into several classes. The analyst next combines the clusters by hand to create a smaller set of groups that correspond to a useful landcover classification. The remaining image pixels are then assigned to one of the aggregated cluster groups by use of a per-pixel classifier. Since the cluster aggregation process frequently creates groups with multivariate shapes ill suited for parametric classifiers, there has been renewed interest in nonparametric methods for the task. This research reports …
An Iterative Approach To Multisensor Sea Ice Classification, David G. Long, Mark R. Drinkwater, Quinn P. Remund
An Iterative Approach To Multisensor Sea Ice Classification, David G. Long, Mark R. Drinkwater, Quinn P. Remund
Faculty Publications
Characterizing the variability in sea ice in the polar regions is fundamental to an understanding of global climate and the geophysical processes governing climate changes. Sea ice can be grouped into a number of general classes with different characteristics. Multisensor data from NSCAT, ERS-2, and SSM/I are reconstructed into enhanced resolution imagery for use in ice-type classification. The resulting twelve-dimensional data set is linearly transformed through principal component analysis to reduce data dimensionality and noise levels. An iterative statistical data segmentation algorithm is developed using maximum likelihood (ML) and maximum a posteriori (MAP) techniques. For a given ice type, the …
Diversity Performance Of Dual-Antenna Handsets Near Operator Tissue, Michael A. Jensen, Bruce M. Green
Diversity Performance Of Dual-Antenna Handsets Near Operator Tissue, Michael A. Jensen, Bruce M. Green
Faculty Publications
This paper presents a computational and experimental study of the diversity performance of two dual-antenna handsets operating indoors in the 902-928 MHz industrial, scientific, and medical (ISM) band. Of particular interest is the effect of the operator tissue on the diversity operation. Key indicators of diversity gain such as branch mean effective gain (MEG) and envelope correlation coefficient are obtained from finite-difference time-domain (FDTD) method simulations as well as from experimental measurements in three different indoor environments. Diversity gain for the handsets is also measured directly. Reasonable agreement is observed between the experimental and simulated results, with both approaches indicating …
Gan-Algan Heterostructure Field-Effect Transistors Over Bulk Gan Substrates, M. Asif Khan, J. W. Yang, W. Knap, E. Frayssinet, X. Hu, Grigory Simin, P. Prystawko, M. Leszczynski, I. Grzegory, S. Porowski, R. Gaska, M. S. Shur, B. Beaumont, M. Teisseire, G. Neu
Gan-Algan Heterostructure Field-Effect Transistors Over Bulk Gan Substrates, M. Asif Khan, J. W. Yang, W. Knap, E. Frayssinet, X. Hu, Grigory Simin, P. Prystawko, M. Leszczynski, I. Grzegory, S. Porowski, R. Gaska, M. S. Shur, B. Beaumont, M. Teisseire, G. Neu
Faculty Publications
We report on AlGaN/GaN heterostructures and heterostructurefield-effect transistors(HFETs) fabricated on high-pressure-grown bulk GaN substrates. The 2delectron gas channel exhibits excellent electronic properties with room-temperature electron Hall mobility as high as μ=1650 cm2/V s combined with a very large electron sheet density ns≈1.4×1013 cm−2.The HFET devices demonstrated better linearity of transconductance and low gate leakage, especially at elevated temperatures. We also present the comparative study of high-current AlGaN/GaN HFETs(nsμ>2×1016 V−1 s−1) grown on bulk GaN, sapphire, and SiC substrates under the same conditions. We demonstrate that in …
X-Ray Rocking Curve Analysis Of Tetragonally Distorted Ternary Semiconductors On Mismatched (001) Substrates, X. Zhang, David W. Parent, P. Li, A. Rodriguez, G. Zhao, J. Ayers, F. Jain
X-Ray Rocking Curve Analysis Of Tetragonally Distorted Ternary Semiconductors On Mismatched (001) Substrates, X. Zhang, David W. Parent, P. Li, A. Rodriguez, G. Zhao, J. Ayers, F. Jain
Faculty Publications
For ternary heteroepitaxial layers, the independent determination of the composition and state of strain requires x-ray rocking curve measurements for at least two different hkl reflections because the relaxed lattice constant is a function of the composition. The usual approach involves the use of one symmetric reflection and one asymmetric reflection. Two rocking curves are measured at opposing azimuths for each hkl reflection. Thus, it is possible to account for tilting of the hkl planes in the epitaxial layer with respect to the hkl planes in the substrate, by averaging the peak separations obtained at the opposing azimuths. This procedure …
Accumulation Hole Layer In P-Gan/Algan Heterostructures, M. S. Shur, A. D. Bykhovski, R. Gaska, J. W. Yang, Grigory Simin, M. A. Khan
Accumulation Hole Layer In P-Gan/Algan Heterostructures, M. S. Shur, A. D. Bykhovski, R. Gaska, J. W. Yang, Grigory Simin, M. A. Khan
Faculty Publications
We present the results on piezoelectric and pyroelectricdoping in AlGaN-on-GaN and GaN-on-AlGaN heterostructures and demonstrate p-GaN/AlGaN structures with accumulation hole layer. Our results indicate that polarization charge can induce up to 5×1013 cm−2 holes at the AlGaN/GaN heterointerfaces. We show that the transition from three-dimensional (3D) to two-dimensional (2D) hole gas can be only achieved for hole sheet densities on the order of 1013 cm−2 or higher. At lower densities, only 3D-hole accumulation layer may exist. These results suggest that a piezoelectrically induced 2D-hole gas can be used for the reduction of the base spreading resistance …
Multilevel Coded Modulation For Unequal Error Protection And Multistage Decoding—Part Ii: Asymmetric Constellations, Motohiko Isaka, Marc P. C. Fossorier, Robert H. Morelos-Zaragoza, Shu Lin, Hideki Imai
Multilevel Coded Modulation For Unequal Error Protection And Multistage Decoding—Part Ii: Asymmetric Constellations, Motohiko Isaka, Marc P. C. Fossorier, Robert H. Morelos-Zaragoza, Shu Lin, Hideki Imai
Faculty Publications
In this paper, multilevel coded asymmetric modulation with multistage decoding and unequal error protection (UEP) is discussed. These results further emphasize the fact that unconventional signal set partitionings are more promising than traditional (Ungerboeck-type) partitionings, to achieve UEP capabilities with multilevel coding and multistage decoding. Three types of unconventional partitionings are analyzed for asymmetric 8-PSK and 16-QAM constellations over the additive white Gaussian noise channel to introduce design guidelines. Generalizations to other PSK and QAM type constellations follow the same lines. Upper bounds on the bit-error probability based on union bound arguments are first derived. In some cases, these bounds …
3d Outside Cell Interference Factor For An Air-Ground Cdma ‘Cellular’ System, David W. Matolak
3d Outside Cell Interference Factor For An Air-Ground Cdma ‘Cellular’ System, David W. Matolak
Faculty Publications
We compute the outside-cell interference factor of a code-division multiple-access (CDMA) system for a three-dimensional (3-D) air-to-ground (AG) "cellular-like" network consisting of a set of uniformly distributed ground base stations and airborne mobile users. The CDMA capacity is roughly inversely proportional to the outside-cell interference factor. It is shown that for the nearly free-space propagation environment of these systems, the outside-cell interference factor can be larger than that for terrestrial propagation models (as expected) and depends approximately logarithmically upon both the cell height and cell radius.
Modeling The Statistical Time And Angle Of Arrival Characteristics Of An Indoor Multipath Channel, Michael A. Jensen, Brian D. Jeffs, A. Lee Swindlehurst, Quentin H. Spencer
Modeling The Statistical Time And Angle Of Arrival Characteristics Of An Indoor Multipath Channel, Michael A. Jensen, Brian D. Jeffs, A. Lee Swindlehurst, Quentin H. Spencer
Faculty Publications
Most previously proposed statistical models for the indoor multipath channel include only time of arrival characteristics. However, in order to use statistical models in simulating or analyzing the performance of systems employing spatial diversity combining, information about angle of arrival statistics is also required. Ideally, it would be desirable to characterize the full spare-time nature of the channel. In this paper, a system is described that was used to collect simultaneous time and angle of arrival data at 7 GHz. Data processing methods are outlined, and results obtained from data taken in two different buildings are presented. Based on the …
Lattice And Energy Band Engineering In Alingan/Ga Heterostructures, M. Asif Khan, J. W. Yang, Grigory Simin, R. Gaska, M. S. Shur, Hans-Conrad Zur Loye, G. Tamulaitis, A. Zukauskas, David J. Smith, D. Chandrasekhar, R. Bicknell-Tassius
Lattice And Energy Band Engineering In Alingan/Ga Heterostructures, M. Asif Khan, J. W. Yang, Grigory Simin, R. Gaska, M. S. Shur, Hans-Conrad Zur Loye, G. Tamulaitis, A. Zukauskas, David J. Smith, D. Chandrasekhar, R. Bicknell-Tassius
Faculty Publications
We report on structural, optical, and electrical properties of AlxInyGa1−x−yNGaNheterostructures grown on sapphire and 6H–SiC substrates. Our results demonstrate that incorporation of In reduces the lattice mismatch, Δa, between AlInGaN and GaN, and that an In to Al ratio of close to 1:5 results in nearly strain-free heterostructures. The observed reduction in band gap,ΔEg, determined from photoluminescence measurements, is more than 1.5 times higher than estimated from the linear dependencies of Δa and ΔEg on the In molar fraction. The incorporation of In and resulting changes in the built-in strain in …
Multilevel Coded Modulation For Unequal Error Protection And Multistage Decoding—Part I: Symmetric Constellations, Robert H. Morelos-Zaragoza, Marc P. C. Fossorier, Shu Lin, Hideki Imai
Multilevel Coded Modulation For Unequal Error Protection And Multistage Decoding—Part I: Symmetric Constellations, Robert H. Morelos-Zaragoza, Marc P. C. Fossorier, Shu Lin, Hideki Imai
Faculty Publications
In this paper, theoretical upper bounds and computer simulation results on the error performance of multilevel block coded modulations for unequal error protection (UEP) and multistage decoding are presented. It is shown that nonstandard signal set partitionings and multistage decoding provide excellent UEP capabilities beyond those achievable with conventional coded modulation. The coding scheme is designed in such a way that the most important information bits have a lower error rate than other information bits. The large effective error coefficients, normally associated with standard mapping by set partitioning, are reduced by considering nonstandard partitionings of the underlying signal set. The …
Selective Area Deposited Blue Gan-Ingan Multiple-Quantum Well Light Emitting Diodes Over Silicon Substrates, J. W. Yang, A. Lunev, Grigory Simin, A. Chitnis, M. Shatalov, M. Asif Khan, Joseph E. Van Nostrand, R. Gaska
Selective Area Deposited Blue Gan-Ingan Multiple-Quantum Well Light Emitting Diodes Over Silicon Substrates, J. W. Yang, A. Lunev, Grigory Simin, A. Chitnis, M. Shatalov, M. Asif Khan, Joseph E. Van Nostrand, R. Gaska
Faculty Publications
We report on fabrication and characterization of blue GaN–InGaN multi-quantum well (MQW)light-emitting diodes(LEDs) over (111) silicon substrates. Device epilayers were fabricated using unique combination of molecular beam epitaxy and low-pressure metalorganic chemical vapor depositiongrowth procedure in selective areas defined by openings in a SiO2mask over the substrates. This selective area deposition procedure in principle can produce multicolor devices using a very simple fabrication procedure. The LEDs had a peak emission wavelength of 465 nm with a full width at half maximum of 40 nm. We also present the spectral emission data with the diodes operating up to 250 …
On The Error Performance Of 8-Vsb Tcm Decoder For Atsc Terrestrial Broadcasting Of Digital Television, Dojun Rhee, Robert H. Morelos-Zaragoza
On The Error Performance Of 8-Vsb Tcm Decoder For Atsc Terrestrial Broadcasting Of Digital Television, Dojun Rhee, Robert H. Morelos-Zaragoza
Faculty Publications
The error performance of various 8-VSB TCM decoders for reception of terrestrial digital television is analyzed. In previous work, 8-state TCM decoders were proposed and implemented for terrestrial broadcasting of digital television. In this paper, the performance of a 16-state TCM decoder is analyzed and simulated. It is shown that not only a 16-state TCM decoder outperforms one with 8-states, but it also has much smaller error coefficients.
Improved Resolution Backscatter Measurements With The Seawinds Pencil-Beam Scatterometer, David G. Long, Michael W. Spencer, Chialin T. Wu
Improved Resolution Backscatter Measurements With The Seawinds Pencil-Beam Scatterometer, David G. Long, Michael W. Spencer, Chialin T. Wu
Faculty Publications
The SeaWinds scatterometer was launched on the NASA QuikSCAT spacecraft in June 1999 and is planned for the Japanese ADEOS-II mission in 2000. In addition to generating a global Ku-band backscatter data set useful for a variety of climate studies, these flights will provide ocean-surface wind estimates for use in operational weather forecasting. SeaWinds employs a compact "pencil-beam" design rather than the "fan-beam" approach previously used with SASS on Seasat, NSCAT on ADEOS-I, and the AMI scatterometer on ERS-1, 2. As originally envisioned and reported, the resolution of the SeaWinds backscatter measurements were to be antenna-beamwidth limited. In order to …