A study of high density bit transition requirements versus the effects on BCH error correcting codes

The use of PN sequence generators to create a minimum number of transitions in an NRZ bit stream is described. The CSG encoder/decoder design was constructed and demonstrated

VAS demonstration: (VISSR Atmospheric Sounder) description

The VAS Demonstration (VISSR Atmospheric Sounder) is a project designed to evaluate the VAS instrument as a remote sensor of the Earth's atmosphere and surface. This report describes the instrument and ground processing system, the instrument performance, the valiation as a temperature and moisture profiler compared with ground truth and other satellites, and assesses its performance as a valuable meteorological tool. The report also addresses the availability of data for scientific research

A study of high density bit transition requirements versus the effects on BCH error correcting coding

Several methods for increasing bit transition densities in a data stream are summarized, discussed in detail, and compared against constraints imposed by the 2 MHz data link of the space shuttle high rate multiplexer unit. These methods include use of alternate pulse code modulation waveforms, data stream modification by insertion, alternate bit inversion, differential encoding, error encoding, and use of bit scramblers. The psuedo-random cover sequence generator was chosen for application to the 2 MHz data link of the space shuttle high rate multiplexer unit. This method is fully analyzed and a design implementation proposed

Planning assistance for the NASA 30/20 GHz program. Network control architecture study.

Network Control Architecture for a 30/20 GHz flight experiment system operating in the Time Division Multiple Access (TDMA) was studied. Architecture development, identification of processing functions, and performance requirements for the Master Control Station (MCS), diversity trunking stations, and Customer Premises Service (CPS) stations are covered. Preliminary hardware and software processing requirements as well as budgetary cost estimates for the network control system are given. For the trunking system control, areas covered include on board SS-TDMA switch organization, frame structure, acquisition and synchronization, channel assignment, fade detection and adaptive power control, on board oscillator control, and terrestrial network timing. For the CPS control, they include on board processing and adaptive forward error correction control

Integrated source and channel encoded digital communication system design study

The particular Ku-band carrier, PN despreading, and symbol synchronization strategies, which were selected for implementation in the Ku-band transponder aboard the orbiter, were assessed and evaluated from a systems performance viewpoint, verifying that system specifications were met. A study was performed of the design and implementation of tracking techniques which are suitable for incorporation into the Orbiter Ku-band communication system. Emphasis was placed on maximizing tracking accuracy and communication system flexibility while minimizing cost, weight, and system complexity of Orbiter and ground systems hardware. The payload communication study assessed the design and performance of the forward link and return link bent-pipe relay modes for attached and detached payloads. As part of this study, a design for a forward link bent-pipe was proposed which employs a residual carrier but which is tracked by the existing Costas loop

V2368 Oph: An eclipsing and double-lined spectroscopic binary used as a photometric comparison star for U Oph

The A-type star HR 6412 = V2368 Oph was used by several investigators as a photometric comparison star for the known eclipsing binary U Oph but was found to be variable by three independent groups, including us. By analysing series of new spectral and photometric observations and a critical compilation of available radial velocities, we were able to find the correct period of light and radial-velocity variations and demonstrate that the object is an eclipsing and double-lined spectroscopic binary moving in a highly eccentric orbit. We derived a linear ephemeris T min.I = HJD (2454294.67 +/- 0.01) + (38.32712 +/- 0.00004)d x E and estimated preliminary basic physical properties of the binary. The dereddened UBV magnitudes and effective temperatures of the primary and secondary, based on our light- and velocity-curve solutions, led to distance estimates that agree with the Hipparcos distance within the errors. We find that the mass ratio must be close to one, but the limited number and wavelength range of our current spectra does not allow a truly precise determination of the binary masses. Nevertheless, our results show convincingly that both binary components are evolved away from the main sequence, which makes this system astrophysically very important. There are only a few similarly evolved A-type stars among known eclipsing binaries. Future systematic observations and careful analyses can provide very stringent tests for the stellar evolutionary theory.Comment: 10 pages, 7 figs, in press 2011 A&

Improved Signal Detection for Ambient Backscatter Communications

In ambient backscatter communication (AmBC) systems, passive tags connect to a reader by reflecting an ambient radio frequency (RF) signal. However, the reader may not know the channel states and RF source parameters and can experience interference. The traditional energy detector (TED) appears to be an ideal solution. However, it performs poorly under these conditions. To address this, we propose two new detectors: (1) A joint correlation-energy detector (JCED) based on the first-order correlation of the received samples and (2) An improved energy detector (IED) based on the p-th norm of the received signal vector. We compare the performance of the IED and TED under generalized noise modeled using the McLeish distribution and derive a general analytical formula for the area under the receiver operating characteristic (ROC) curves. Based on our results, both detectors outperform TED. For example, the probability of detection with a false alarm rate of 1% for JCED and IED is 14% and 5% higher, respectively, compared to TED. These gains are even higher using the direct interference cancellation (DIC) technique, with increases of 16% and 7%, respectively. Overall, our proposed detectors offer better performance than the TED, making them useful tools for improving AmBC system performance.Comment: This paper has got Major Revision by IEEE TGC

Spacelab uplink/downlink data flow and formats

The results of an analysis of the Spacelab (SL) data uplink/downlink structure and those data system elements associated with the support of this data flow are presented. Specific objectives of this report are to present the results of the following analyses: (1) operations of the SL high rate multiplexer, including format structure, data rates, format combinations, format switching, etc.; (2) operations of SL data recorders to include the definition of modes, data rates and forms; (3) operations of the high rate demultiplexer as described above; (4) potential experiment data formats defining formatting parameters to be considered in decommutation analysis; (5) SL computer input/output (I/O) decommutation channels, including the definition of structure, quantity and use of this I/O data; (6) detailed requirements of the data quality monitoring philosophy for this function

Analysis of J/Psi production with the CMS detector at the Large Hadron Collider

The J/psi particle is a vector meson with a mass of 3096.916±0.011 MeV. It has been observed in 1974 by two experiments at Stanford and Brookhaven, and is the first bound state of a charm quark and an anticharm quark ever discovered in the history of particle physics. Differently from lighter quarks, the charm quark is characterized by a rest mass significantly greater than the typical energy scale of Quantum Chromo Dynamics processes, which take place during the binding of the meson. This greater mass results in its constituent quarks being relatively "slow" inside it, justifying a non-relativistic description of its production process. The J/psi, along with other charm-anticharm bound states, represents an important laboratory where the theoretical models of the strong interaction are verified. Heavy mesons are produced in copious amounts in high energy proton-proton collisions, and the recent beginning of experiments at the CERN Large Hadron Collider has given an opportunity to study the behavior of J/psi production at a center-of-mass energy of 7 TeV with the CMS detector. This detector has been designed as a general-purpose one and is capable of good performance in this kinds of studies, especially in the J/psi to mu+ mu- decay channel. Indeed, the past 20 years have seen a revival of interest in the study of the production process of the J/psi. A measurement performed by the CDF experiment in 1992-1993 at the Tevatron p-pbar collider found the production cross-section to be larger than the theoretical prediction by a factor of 50. Consequently, the model in use at the time - the Color Singlet Model - had to be abandoned in favor of a Non-Relativistic QCD description called the Color Octet Model. Recently, also this model has been put into discussion, as the predictions it makes on the polarization of the J/psi seem not to match experimental data by the E866, HERA-B and CDF II experiments, and even more puzzling is the fact that the E866 and HERA-B measurement are inconsistent. A possible explanation of these inconsistencies may be hidden in the different experimental conditions under which these experiments took place (mainly, the detector acceptances), and the fact that the measurements were performed in different frames of reference. Once identified the importance of the cross-section and polarization measurements, I present the cross-section measurement performed on data taken in 2010 with the CMS detector and present the ongoing effort in measuring the J/psi polarization by the CMS collaboration - in which I have worked as a student for the purpose of this thesis. In my thesis I introduce a frame-invariant approach which should overcome these elements and provide a clear picture of the behavior of the polarization (longitudinal, transverse or a combination of these states) as a function of transverse momentum. The measurement requires a series of introductory steps aimed at understanding all aspects of detector response to muons, among them is the calculation of the detector acceptance for the muon pairs with Monte Carlo simulations, the study based on real data of the tracking efficiency, that of muon identification efficiency and that of trigger efficiency, the latter being one of my responsibilities during my work. The efficiency study has been performed by the use of the "Tag and Probe" method for resonances decaying to dimuons, where a muon of the pair is required to pass a series of very tight cuts. The pairs surviving this extreme skimming have the other muon analyzed, in order to perform a statistical measurement on the relevant variable