Thesis (M.S.)--Boise State University, 2010. / Title from t.p. of PDF file (viewed July 20, 2010). Includes abstract. Includes bibliographical references (leaves 73-75).

Made available in DSpace on 2014-06-12T18:08:13Z (GMT). No. of bitstreams: 2 arquivo8044_1.pdf: 436930 bytes, checksum: 4f958f44689dc03881cbb9851fa8e45e (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2002 / Nesta dissertação são investigadas as propriedades magnéticas da interface constituída por um material ferromagnético (FM) e um material antiferromagnético (AF). As amostras investigadas foram preparadas por sputtering dc e foram caracterizadas por ressonância ferromagnética (FMR), magnetometria por efeito Kerr magneto-óptico (MOKE) e susceptibilidade ac (cAC). Os resultados experimentais foram interpretados a partir de um modelo fenomenológico no qual são consideradas a energia livre da camada FM (Zeeman, anisotropia e desmagnetização); a energia devido ao acoplamento na interface (exchange bias) e a energia da parede de domínio que se forma na camada AF. Parâmetros tais como: campo de anisotropia, campo de acoplamento na interface, campo da parede de domínio no AF, etc. são extraídos a partir dos resultados experimentais. É mostrado que os parâmetros extraídos a partir dos resultados de MOKE e cAC são iguais (dentro do erro experimental), por outro lado esses mesmos parâmetros são diferentes daqueles obtidos por FMR. O modelo foi testado em três sistemas com composições diferentes, produzindo resultados consistentes para todas as amostras. Com o objetivo de investigar o deslocamento que ocorre no campo de ressonância ferromagnética em bicamadas FM/AF, investigamos tricamadas nas quais um espaçador não-magnético é depositado entre a camada FM e a camada AF. Os espectros de absorção apresentaram dois modos de ressonância. Um deles apresenta uma variação angular com simetria C2 correspondendo ao modo uniforme do filme FM sem acoplamento. O outro modo ocorre em valores de campo correspondentes ao modo uniforme do filme FM acoplado. Porém a variação angular do campo de ressonância deste segundo modo apresenta nenhuma simetria. Também foram investigados, por susceptibilidade ac, filmes simples policristalinos de permalloy. Os resultados foram interpretados utilizando-se teorias fenomenológicas. Foi mostrado que a introdução termos que levam em conta os grãos policristalinos reproduzem os resultados experimentais

Con la firma del Convenio Binacional Perú - Ecuador se aseguró el correcto funcionamiento, dentro de los parámetros técnicos autorizados, de las estaciones de radiodifusión sonora y de televisión, en la zona de frontera, evitando así problemas de interferencias entre estaciones de radiodifusión de ambos países. Se acordó realizar mediciones conjuntas con la finalidad de verificar el nivel de intensidad de campo eléctrico y ocupación de la canalización asignada a las estaciones de Radiodifusión sonora en FM y Radiodifusión por televisión en las bandas VHF y UHF. Detectándose niveles altos de intensidad de campo en la franja fronteriza, producidos tanto por estaciones de radiodifusión sonora en FM del Perú como del Ecuador, siendo necesaria una pronta solución al problema. Este trabajo presenta una propuesta de solución al problema, realizando modificaciones técnicas en el sistema irradiante, sin cambiar la ubicación de la planta de transmisión y sin disminuir la potencia, mejorando así, su zona de cobertura.

En la Dirección Regional de Transportes y Comunicaciones de Ayacucho (DRTCA), tengo el cargo de Ingeniero II, según documentos de gestión como el Cuadro de Asignación de Personal – CAP y el Cuadro Nominal de Personal – CNP. De acuerdo a los documentos de gestión y normativa actual vigente, la Dirección de Telecomunicaciones, es un órgano de línea de la Dirección Regional, encargada de proponer la política relativa a la prestación de servicios de telecomunicaciones, así como supervisa y evalúa su ejecución de acuerdo a las normas vigentes emitidas por el sector. El MTC, a través del Conglomerado de Proyectos Apoyo a la Comunicación Comunal – CPACC ha trasferido al Gobierno Regional de Ayacucho 105 Sistemas de Televisión instalados desde 1995 al 2005, tal como se detalla en el Anexo. La Dirección de Telecomunicaciones de reciente incorporación a la Estructura Orgánica Interna de la DRTCA, aprobado a través de la Ordenanza Regional N° 012-2009-GRA/CR proyectó la implementación del Proyectó de “Implementación de Recepción de Televisión Vía Satélite y Transmisión de Televisión en Baja Potencia y Radio FM en la Comunidad de Sachabamba, Distrito de Chiara, Provincia de Huamanga, Región Ayacucho”.

[pt] A partir de uma análise de sistemas de modulação em ângulo são feitas comparações entre resultados teóricos correspondentes e resultados experimentais, bem como práticas usualmente adotadas em relação a esses sistemas. A densidade espectral de potência de uma portadora modulada por um sinal multiplex é comparada com aproximações utilizadas na prática, observando-se serem as mesmas bastante satisfatórias. Ainda para um sinal multiplex como sinal modulador é analisada a melhoria de limiar introduzida por um demodulador PLL. Limites teóricos para essa melhoria são comparados com valores experimentais. Para o sinal multiplex como sinal modulador é também calculado o filtro ótimo de pré-ênsafe com restrição de largura de faixa, verificando-se que o mesmo apresenta características bastante semelhantes às do filtro recomendado pelo CCIR. / [en] Angle modulation systems are analysed. Corresponding theoretical results are to experimental results and usual procedures connected to these systems. Power spectral density of a multiplex signal angle modulated carrier is compared to usual approximations, which shoe to be rather satisfactory. Still for a multiplex signal as modulating signal threshold improvement introduced by a PLL demodulador is analysed. Theoretical bounds on this improvement are compared to experimental values. For a multiplex modulating signal an optimal pre-emphasis filter is computed, under a bandwidth constraint. This filter is reasonably similar to the one recommended by CCIR.

<p> This thesis is principally concerned with the performance of the phase-locked FM demodulator under conditions of interference in comparison to the conventional FM demodulator. The linear no interference performance of the phase-locked oscillator is well known, however this aspect is included in the interests of completeness and reference.</p> <p> Mechanisms tor threshold effects in the phase-locked and conventional FM demodulator are discussed and compared. It is shown theoretically and experimentally that the noise threshold is reduced in the phase-locked FM demodulator by virtue of the limits of Ψi (t) being restricted by the noise bandwidth of' the feedback loop. Fall off in baseband signal level in the presence of noise was seen to be a function of θ(t) and (S/N)IF.</p> / Thesis / Master of Engineering (MEngr)

The proposed demodulator is an all-digital implementation of a FM demodulator. The proposed design intends to implement a FM demodulator for high-speed applications, which makes the requirements for analog components minimal. The proposed circuit is an all-digital quadrature demodulator, where the individual components have been implemented without using any multipliers. The topology uses a Pulse width modulation (PWM) block to avoid the need for a DAC. The Xilinx virtex-7 FPGA has been used as the reference device for the work. The circuit is validated through behavioral simulations and the results conclude the proposed circuit demodulates the targeted FM channel and provides the spectrum information for the targeted FM channel / Master of Science / With the rise in popularity of reconfigurable hardware, such as FPGAs, digital signal processing has become one of the most widespread usage of such devices. The major advantage of using FPGAs for implementing signal processing algorithms is that they provide very less time to market and can be re-modeled or modified in easily. Moreover, the netlists designed for FPGAs can be easily translated to ASICs. As wireless communication has become omnipresent, modulation and demodulation schemes have become an area of great interest. With the increase in data rates for the modern-day communication systems, the digital implementation of these algorithms is becoming more and more common. This is further aided by the advancements in high-speed ADCs and the Electronic Design Automation (EDA) tools, which have made the usage of FPGAs lot more feasible and a lot more efficient. This work discusses the demodulation scheme for one of the most widespread modulation algorithms, Frequency Modulation (FM). An all-digital FM demodulator design is proposed for highspeed implementation on FPGAs. The proposed design is an all-digital quadrature I-Q based demodulator.

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / Today’s telemetry environment is becoming increasingly digital. Highly reliable and relatively inexpensive digital recorders readily available, and most telemetry facilities are migrating away from the older analog recorders which are difficult to calibrate and expensive to maintain. Unfortunately, most site managers find they still have one or more “legacy” signals (such as FM-FM, PAM, and pre-detect PCM) that still require analog recording. To exclusively use digital recorders the TM site must integrate some device to convert the analog signals to digital format before recording. Until recently, the TM site managers had very few options short of building custom equipment to convert and capture the legacy signals. One solution available from Racal (for their Storeplex digital recorder) is to purchase their Analog Record/Play Signal Module. Unfortunately, their module uses a 16-bit Sigma-Delta converter and has a maximum bandwidth of 45.5 KHz, which is woefully inadequate for many analog signals. Other manufacturers offer similar solutions with similar bandwidth restrictions. Another solution is to purchase a multiplexor “front-end” which is capable of mixing multiple signal types (both digital and analog) on to the recorder’s serial-digital data stream. This option can provide higher analog bandwidths, but represents a significant investment (greater than $100K and often more than the recorder itself). This paper discusses the conceptualization, design, and performance of a unit to fill the gap between the low-bandwidth analog channel module and the high-end signal multiplexors. We will discuss how high-speed field-programmable gate arrays (FPGAs) can be configured to provide a low-cost interface between the digital recorder and the analog-to-digital converters (ADCs) and digital-to-analog converters (DACs) to capture and playback the analog signals. Our design focuses on achieving the maximum possible bandwidth for each analog signal while ensuring that IRIG-A or IRIG-B timecode are recorded simultaneously (so the analog signals can be later synchronized with their digital counterparts). We have found that such a solution permits multiple analog signals from 400 KHz up to 3 MHz to be easily and inexpensively recorded on the current generation of digital recorders. Our conclusions show that such a device can permit most telemetry sites to transition completely to more reliable, cheaper, and easier-to-maintain digital recorders.

International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The US Air Force is required to protect the lives of individuals and property in areas potentially hazardous as a result of launch vehicle failures occurring from Vandenberg AFB, California. This paper describes the application of modern telemetry processing equipment to the Range Safety function.

Práce shrnuje poznatky ve vývojové posloupnosti o ekonomických vztazích mezi zeměmi ES a ESVO a analyzuje tři současné finanční nástroje zemí ESVO - Finanční mechanismus EHP a Norska na období 2004-2009 a Švýcarský příspěvek (2007-2012). Cílem DP je komparace těchto tří nástrojů a zhodnocení stavu jejich implementace v České republice včetně navržení doporučení.