Digital signal processors

Stranneby, Dag; Walker, William

doi:10.1016/b978-075066344-1/50009-4

Cited by 24 publications

(35 citation statements)

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“…The purpose is to improve the quality of the noise power of the signal analyzed. Assuming that x (n) is a full signal observed along the windows in L; by using the DFT and the signal in frequency domain ω, the full signal can be written as the following power-Welch formula, as explained by Stranneby [24]:…”

Section: Polarization Power Ratio Welch Methodsmentioning

confidence: 99%

Anomalous ULF Emissions and Their Possible Association with the Strong Earthquakes in Sumatra, Indonesia, during 2007-2012

et al. 2015

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Abstract. Eleven strong Sumatran earthquakes, with their epicenter less than 550 km away from the Kototabang (KTB) geomagnetic station (2007)(2008)(2009)(2010)(2011)(2012), were studied to examine the occurrence of anomalous ultra-low frequency emissions (ULF-EM). Anomalous ULF signals, possibly associated with the earthquake's precursors, were determined by the Welch ratio S Z /S H at 0.06 Hz at the KTB station. These ULF anomalies were then compared with geomagnetic data observed from two reference stations in Darwin and Davao, to prevent misinterpretation of global geomagnetic disturbances as precursors. This study aims to analyze the relationship between earthquake magnitude and hypocenter radius, and seismic index against lead time during ULF-EM anomalies. We used the polarization ratio Welch method in terms of power spectrum density to evaluate the geomagnetic data by overlapping windows and applying fast Fourier transform (FFT). The results showed anomalous variations in onset and lead time, determined using the standard deviation controlling the S Z /S H power pattern. Our positive correlation between lead time of ULF emission and earthquake magnitude as well as between lead time and seismic index. It shows a negative correlation between hypocenter distances to KTB station against lead time.

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Section: Polarization Power Ratio Welch Methodsmentioning

confidence: 99%

Anomalous ULF Emissions and Their Possible Association with the Strong Earthquakes in Sumatra, Indonesia, during 2007-2012

et al. 2015

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“…There are many techniques for performing this task. One technique employs digital signal processing, 2 wherein a digital-signal processing chip or a dedicated electronic circuit is used to compare the images serially, bit by bit, and thereby to identify the image with the highest degree of correlation to the target image.…”

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confidence: 99%

Superparallel holographic correlator for ultrafast database searches

et al. 2003

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We describe a superparallel holographic optical correlator that performs two-dimensional spatial and angular multiplexing simultaneously. The key step in this architecture is the use of a holographic multiplexer to split a query image into many copies before it applies them to the holographic database. A holographic demultiplexer, in conjunction with an aperture, is used to identify the location and the angle of the brightest correlation peak. This architecture uses only O͑ p N͒ detector elements to search through N unsorted images in a single query. We demonstrate the basic features of this architecture, using three spatial locations with eight angle-multiplexed images in each location.

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“…Os filtros IIR projetados com auxílio de mapeamento matemático entre uma função analógica e uma função discreta são o equivalente digital dos filtros analógicos [3].…”

Section: Os Tipos De Filtros Projetados Nesse Trabalho Sãounclassified

“…Hoje em dia, algumas das tecnologias usadas para o processamento digital de sinais incluem microprocessadores, FPGAs, controladores digitais de sinais, entre outros [3].…”

Section: Introductionunclassified

“…Os coeficientes do filtro digital podem ser também mais facilmente manipulados, tornando possíveis projetos que são impraticáveis para filtros analógi-cos. Além disso, essa característica torna mais fácil a construção de filtros adaptativos e filtros com parâmetros definidos por usuários [4]. Suas aplicações são muitas, sendo um elemento essencial de sistemas eletrônicos do dia a dia como rádios e celulares, mas que também são usados na área biomédica e na instrumentação [3]. Exemplos do uso de filtros digitais em aúdio incluem amplificadores, equalizadores, reverberadores, dispositivos de eco e defasadores [5].…”

Digital signal processors

Cited by 24 publications

References 0 publications

Anomalous ULF Emissions and Their Possible Association with the Strong Earthquakes in Sumatra, Indonesia, during 2007-2012

Anomalous ULF Emissions and Their Possible Association with the Strong Earthquakes in Sumatra, Indonesia, during 2007-2012

Superparallel holographic correlator for ultrafast database searches

Desenvolvimento De Uma Interface Gráfica Para Projeto De Filtros Digitais

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