5 research outputs found
Design of Analog-to-Digital Converters with Embedded Mixing for Ultra-Low-Power Radio Receivers
In the field of radio receivers, down-conversion methods usually rely on one (or more)
explicit mixing stage(s) before the analog-to-digital converter (ADC). These stages not
only contribute to the overall power consumption but also have an impact on area and can
compromise the receiver’s performance in terms of noise and linearity. On the other hand,
most ADCs require some sort of reference signal in order to properly digitize an analog
input signal. The implementation of this reference signal usually relies on bandgap
circuits and reference buffers to generate a constant, stable, dc signal. Disregarding this
conventional approach, the work developed in this thesis aims to explore the viability
behind the usage of a variable reference signal. Moreover, it demonstrates that not only
can an input signal be properly digitized, but also shifted up and down in frequency,
effectively embedding the mixing operation in an ADC. As a result, ADCs in receiver
chains can perform double-duty as both a quantizer and a mixing stage. The lesser known
charge-sharing (CS) topology, within the successive approximation register (SAR) ADCs,
is used for a practical implementation, due to its feature of “pre-charging” the reference
signal prior to the conversion. Simulation results from an 8-bit CS-SAR ADC designed in
a 0.13 ÎĽm CMOS technology validate the proposed technique
Design and analysis of multi-element antenna systems and agile radiofrequency frontends for automotive applications
Vehicular connectivity serves as one of the major enabling technologies for
current applications like driver assistance, safety and infotainment as well as
upcoming features like highly automated vehicles - all of which having certain
quality of service requirements, e. g. datarate or reliability. This work focuses on
vehicular integration of multiple-input-multiple-output (MIMO) capable multielement
antenna systems and frequency-agile radio frequency (RF) front ends
to cover current and upcoming connectivity needs. It is divided in four major
parts. For each part, mostly physical layer effects are analyzed (any performance
lost on physical layer, cannot be compensated in higher layers), sensitivities are
identified and novel concepts are introduced based on the status-quo findings.Fahrzeugvernetzung dient als eine der wesentlichsten Befähigungstechnologien
fĂĽr moderne Fahrerassistenzsysteme und zukĂĽnftig auch hochautomatisiertes
Fahren. Sowohl die heutigen als auch zukĂĽnftige Anwendungen haben besondere
Dienstgüteanforderungen, z.B. in Bezug auf die Datenrate oder Verlässlichkeit.
Im Rahmen dieser Arbeit wird die Integration von Mehrantennensystemen fĂĽr
MIMO-Funkanwendungen (MIMO: engl. Multiple Input Multiple Output) sowie
von frequenzagilen Hochfrequenzfrontends im Fahrzeugumfeld untersucht, um
so eine technische Grundlage fĂĽr zukĂĽnftige Anforderungen an die automobile
Vernetzung anbieten zu können. Die dabei gewonnenen Erkenntnisse lassen sich
in vier Teile gliedern. Grundsätzlich konzentrieren sich die Untersuchungen vorrangig
auf die physikalische Ebene. Auf Basis des aktuellen Status Quo werden
Sensitivitäten herausgearbeitet, neue Konzepte hergeleitet und entwickelt
Undersampling bandpass modulator architectures
Continuous-time delta sigma modulators -- Undersampling Delta-sigma modulators for radio receivers -- A novel continuous-time delta sigma modulator -- New delta modulator based on undersampling
Abstracts on Radio Direction Finding (1899 - 1995)
The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography).
Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM.
The contents of these files are:
1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format];
2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format];
3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion