227 research outputs found
The Telecommunications and Data Acquisition Report
This quarterly publication provides archival reports on developments in programs managed by JPL's Telecommunications and Mission Operations Directorate (TMOD), which now includes the former Telecommunications and Data Acquisition (TDA) Office. In space communications, radio navigation, radio science, and ground-based radio and radar astronomy, it reports on activities of the Deep Space Network (DSN) in planning, supporting research and technology, implementation, and operations. Also included are standards activity at JPL for space data and information systems and reimbursable DSN work performed for other space agencies through NASA. The preceding work is all performed for NASA's Office of Space Communications (OSC). TMOD also performs work funded by other NASA program offices through and with the cooperation of OSC. The first of these is the Orbital Debris Radar Program funded by the Office of Space Systems Development. It exists at Goldstone only and makes use of the planetary radar capability when the antennas are configured as science instruments making direct observations of the planets, their satellites, and asteroids of our solar system. The Office of Space Sciences funds the data reduction and science analyses of data obtained by the Goldstone Solar System Radar. The antennas at all three complexes are also configured for radio astronomy research and, as such, conduct experiments funded by the National Science Foundation in the U.S. and other agencies at the overseas complexes. These experiments are either in microwave spectroscopy or very long baseline interferometry. Finally, tasks funded under the JPL Director's Discretionary Fund and the Caltech President's Fund that involve TMOD are included. This and each succeeding issue of 'The Telecommunications and Data Acquisition Progress Report' will present material in some, but not necessarily all, of the aforementioned programs
Characterization of systems for software defined radio
Mestrado em Engenharia Electrónica e TelecomunicaçõesEsta dissertação insere-se na área de electrónica de rádio frequência, mais
precisamente na caracterização de sistemas para rádios definidos por software
(SDR). Um SDR é aquele que possui a flexibilidade para sintonizar, filtrar,
ajustar a taxa de transmissão e controlar o tipo de modulação através de
software. O aparecimento de novas tecnologias no mercado obriga à utilização
de uma quantidade considerável de hardware nos dispositivos de
transmissão/recepção, assim uma solução consiste no uso de arquitecturas de
SDR onde a conversão do sinal analógico para digital é executada o mais
próximo possível da antena e, sendo depois todo o processamento efectuado
digitalmente. Assim, nesta tese, é apresentado um modelo comportamental
para receptores de SDR, que leva em conta os elementos chave da distorção
não linear. Além disso, são apresentadas algumas comparações entre
simulações e medidas usando sinais multi-seno e WiMax usando um receptor
ideal de SDR. Finalmente, é proposto um novo sistema de caracterização para
dispositivos de SDR.
ABSTRACT: This dissertation is related to the radio frequency area, more specifically to the
characterization of systems for software-defined radio. A software-defined radio
is one that has the flexibility to tune, filter, set the transmission rate and control
the modulation type only by software. The emergence of new technologies in
the market forces the use of a considerable quantity of hardware in the
transceivers systems, so a viable solution for this is to use SDR solutions
where the analogue to digital conversion is made closest possible of the
antenna and then make all the processing digitally. So, in this dissertation, a
behavioral model for SDR front end receiver evaluation, that captures the key
elements of the nonlinear distortion, is proposed. Moreover, some comparisons
between measured and simulated results under multisine and WiMax
excitations are presented using the ideal SDR receiver. Finally, a new
instrumentation system for characterization of SDR front ends is proposed
A study of data coding technology developments in the 1980-1985 time frame, volume 2
The source parameters of digitized analog data are discussed. Different data compression schemes are outlined and analysis of their implementation are presented. Finally, bandwidth compression techniques are given for video signals
The investigation of bandwidth efficient coding and modulation techniques
The New Mexico State University Center for Space Telemetering and Telecommunications systems has been, and is currently, engaged in the investigation of trellis-coded modulation (TCM) communication systems. In particular, TCM utilizing M-ary phase shift keying is being studied. The study of carrier synchronization in a TCM environment, or in MPSK systems in general, has been one of the two main thrusts of this grant. This study has involved both theoretical modelling and software simulation of the carrier synchronization problem
ULTRA-LOW-JITTER, MMW-BAND FREQUENCY SYNTHESIZERS BASED ON A CASCADED ARCHITECTURE
Department of Electrical EngineeringThis thesis presents an ultra-low-jitter, mmW-band frequency synthesizers based on a cascaded
architecture. First, the mmW-band frequency synthesizer based on a CP PLL is presented. At the
first stage, the CP PLL operating at GHz-band frequencies generated low-jitter output signals due
to a high-Q VCO. At the second stage, an ILFM operating at mmW-band frequencies has a wide
injection bandwidth, so that the jitter performance of the mmW-band output signals is determined
by the GHz-range PLL. The proposed ultra-low-jitter, mmW-band frequency synthesizer based on
a CP PLL, fabricated in a 65-nm CMOS technology, generated output signals from GHz-band
frequencies to mmW-band frequencies, achieving an RMS jitter of 206 fs and an IPN of ???31 dBc.
The active silicon area and the total power consumption were 0.32 mm2 and 42 mW, respectively.
However, due to a large in-band phase noise contribution of a PFD and a CP in the CP PLL, this
first stage was difficult to achieve an ultra-low in-band phase noise. Second, to improve the in-band
phase noise further, the mmW-band frequency synthesizer based on a digital SSPLL is presented.
At the first stage, the digital SSPLL operating at GHz-band frequencies generated ultra-low-jitter
output signals due to its sub-sampling operation and a high-Q GHz VCO. To minimize the
quantization noise of the voltage quantizer in the digital SSPLL, this thesis presents an OSVC as a
voltage quantizer while a small amount of power was consumed. The proposed ultra-low-jitter,
mmW-band frequency synthesizer fabricated in a 65-nm CMOS technology, generated output
signals from GHz-band frequencies to mmW-band frequencies, achieving an RMS jitter of 77 fs
and an IPN of ???40 dBc. The active silicon area and the total power consumption were 0.32 mm2 and
42 mW, respectively.clos
New methods in image compression using multi-level transforms and adaptive statistical encoDing
The need to meet the demand for high quality digital images, with comparatively modest storage requirements, is driving the development of new image compression techniques. This demand has spurred new techniques based on time to frequency spatial transformation methods. At the core of these methods are a family of transformations built on basis sets called wavelets. The wavelet transform permits an image to be represented in a substantially reduced space by transferring the energy of the image to a smaller set of coefficients. Although these techniques are lossy as the compression ratio rises, very adequate reconstructions can be made from surprisingly small sets of coefficients. This work explores the transformation process, storage of the representation and the application of these techniques to 24-bit color images. A working color image compression model is illustrated
Perceptual models in speech quality assessment and coding
The ever-increasing demand for good communications/toll
quality speech has created a renewed interest into the
perceptual impact of rate compression. Two general areas are
investigated in this work, namely speech quality assessment
and speech coding.
In the field of speech quality assessment, a model is
developed which simulates the processing stages of the
peripheral auditory system. At the output of the model a
"running" auditory spectrum is obtained. This represents
the auditory (spectral) equivalent of any acoustic sound such
as speech. Auditory spectra from coded speech segments serve
as inputs to a second model. This model simulates the
information centre in the brain which performs the speech
quality assessment. [Continues.
Engineering Education and Research Using MATLAB
MATLAB is a software package used primarily in the field of engineering for signal processing, numerical data analysis, modeling, programming, simulation, and computer graphic visualization. In the last few years, it has become widely accepted as an efficient tool, and, therefore, its use has significantly increased in scientific communities and academic institutions. This book consists of 20 chapters presenting research works using MATLAB tools. Chapters include techniques for programming and developing Graphical User Interfaces (GUIs), dynamic systems, electric machines, signal and image processing, power electronics, mixed signal circuits, genetic programming, digital watermarking, control systems, time-series regression modeling, and artificial neural networks
The deep space network
Progress is reported in flight project support, tracking and data acquisition, research technology, network engineering, hardware and software implementation, and operations
Sequence codes
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