P. V. G. Castellanos

Preliminary field tests results of ISDB-Tb digital TV transmission in the VHF-high band

This paper presents preliminary results of field measurements carried out for evaluating the operation of the ISDB-TB standard digital TV in the VHF-high band. Measurements were performed in urban, suburban and rural areas in a medium-sized Brazilian city. The analysis includes results of static reception measurements for evaluating the received field strength and the signal to noise ratio thresholds for correct signal decoding. A comparison with theoretical values of field strength is also presented.

Performance of Recommendation ITU-R P.1812-3 Model in the Propagation Loss Prediction for Digital Terrestrial Television in Caracas (Venezuela) and Belem (Brazil)

Among the different technologies with important implications today in such areas as education, health and business, videostreaming is highlighted. This considering how this technology facilitates the access to multimedia content remotely, live or offline. The goal of this paper is to propose a test environment for the support of the video streaming service, using open source tools. Moreover, this work proposes, as part of the environment, a stress measurement tool (Hermes), which allows obtaining the response times to establish multiple RTSP connections to streaming servers. The methodology used in this work is divided into four phases: analysis of technologies and tools, configuration of the video streaming environment, design and implementation of Hermes, and finally tests. This methodology allowed the construction of the test environment and its evaluation, through the stress measurement tool Hermes. Finally, in this work we demonstrate how the proposed environment becomes a reference point for different application environments that require the implementation of a video streaming service.Se aplico la mecanica de solidos hiperelasticos al estudio del comportamiento del tubo arterial, ya que es un medio consolidado en la comprension de fenomenos de interes para los profesionales de la medicina y de la ingenieria biomedica. En el caso del organo en cuestion, su estudio se realizo mediante el modelado como un recipiente cilindrico de pared gruesa, donde la funcion de energia empleada permitio considerar aspectos microestructurales como la anisotropia y la dispersion de fibras de colageno. En el problema de equilibrio estatico en el que se implementa esta caracterizacion se representaron las capas media y adventicia de la pared arterial. La solucion expedita del problema de valores en la frontera resultante es posible gracias a la asuncion de un patron de deformacion de simetria axial. Se encontro que el factor de dispersion de fibras y los demas parametros adimensionales del mismo orden de magnitud tienen el rol dominante en la rigidez radial del tubo arterial. Los resultados se presentan utilizando grupos adimensionales, lo cual facilita la interpretacion rapida del efecto de los numerosos parametros que emergen

Preliminary results of the characterization of an in tunnel radio channel at 700MHz

The characterization of propagation mechanisms inside tunnels are important for the development of models for the planning of wireless communication systems in urban areas. This paper presents the first results of a measurement campaign conducted at 700 MHz in a 2.2 km urban tunnel. The path loss dependence with distance traveled inside the tunnel and the dispersion parameters of the channel were obtained.

Experimental analysis of the signal-to-noise ratio of digital ISDB-TB TV receivers and multipath in the VHF-high band

This paper presents an evaluation of the performance of digital TV receivers focusing the parameter signal-to-noise ratio achieved from measurements in laboratory tests and from field tests, and also the multipath data achieved from field tests. The mentioned field tests are a field measurement campaign performed in Brazil aiming the evaluation of ISDB-TB standard digital TV operation in the VHF-high band. From the static measurements of field tests, the parameter signal-to-noise ratio was achieved employing two methodologies, one from direct measurements and the second from noise injection. These results were compared to laboratory tests and to the technical norm of operation in the VHF band. An assessment of the influence of multipath in the digital signal reception and some correlation to the measured signal-to-noise ratio values is also presented.

Measurements of Field Strength and HD Radio Reception Quality at VHF

This letter presents the results of field trials conducted in Brazil to evaluate the performance of digital broadcasting systems. Analog FM and digital HD radio signals broadcasting the same content were simultaneously transmitted in the urban and suburban areas of the city of Belo Horizonte in Brazil. A mobile unit recorded the received signal intensity and reception quality along radial routes of up to 24 km from the transmitter, thereby enabling the comparative assessment of the systems performance and the evaluation of the propagation loss.

Preliminary results of channel characterization at 700MHz band in urban and rural regions

This paper presents the preliminary results of channel characterization in the 700 MHz band, based on measurements of an OFDM modulated signal in urban and rural environments. This band will be used for mobile wideband communications in Brazil. An investigation of the dispersion parameters of the channel was carried out in the two different environments aiming a comparison between results of mean excess delay and RMS delay spread, useful for systems design.

Initial results of HD radio AM trials in Brazil

This paper describes the experimental setup and presents some results of HD Radio AM digital system trials that were carried out in Brazil. The experiment is part of a series of field trials that are being conducted by the Brazilian Government to evaluate the performance of digital standards, which includes campaigns at MW, HF and VHF frequency bands. Simultaneous transmission of AM analog and HD Radio digital broadcasted the same content. The results presented here include results of the daytime and nighttime measurements performed in São Paulo.

Medium wave DRM trials in Brazil — Initial results

This paper describes the experimental setup and presents initial results of medium wave propagation measurements campaigns that are being carried out in Brazil. The experiment is part of a series of field trials that are being conducted by the Brazilian Government to evaluate the performance of DRM standard in this country, which includes campaigns at MW, HF and VHF frequency bands in the cities of São Paulo, Rio de Janeiro and Belo Horizonte. A hybrid signal, composed of an analog AM signal and a digital DRM signal, with the same content, were broadcasted in diurnal and nocturnal transmissions. The results presented here include daytime and nighttime statistics of the measurements performed in São Paulo.