XXXI Simpósio Brasileiro de Telecomunicações

Este artigo apresenta a concepção de um transceptor capaz de realizar a digitalização fotônica de sinais do tipo Rádio-sobre-Fibra, e no processo inverso recuperar o sinal analógico. A principal contribuição é a descrição do módulo receptor. Trata-se de um sistema formado por diversos circuitos ópticos interconectados, quase todos baseados na...

In this work, real environmental data are monitored with a multihop Wireless Sensor Network (WSN). An algorithm for energy conservation of sensor nodes is used to extend the network autonomy, increasing its lifetime. Temperature and hu- midity signals are sensed by nodes and transmitted to a sink node. Both signals are reconstructed at the sink...

This paper investigates the multicondition training (MT) technique for improving the speaker identification in non-stationary acoustic noises. The main contribution is the adoption of MT together with a speech enhancement approach based on the empirical mode decomposition. The MT techniques adopted in this work are based on artificial noises with white...

This work proposes a remote monitoring system of ECG signals. The ECG signal is generated with an algorithm called ecgsyn, and it is transmitted in a real ZigBee network. The signal received by the sink node is stored in a file, and is sent to a web server in the Internet. Thus, after an electrocardiogram test, doctors can view the biometric data in...

Este trabalho propõe dois esquemas hı́bridos de transmissão com multiplexação para dois usuários assistidos por relays, onde estes últimos estão geograficamente espalhados em três regiões e distribuı́dos em clusters, denominados R a , R b , e R c . Mais especificamente, R a e R b encaminham as informações provenientes das fontes (usuários) 1 e 2,...

The aim of this paper is to verify the performance of signal processing techniques in antenna synthesis. It is possible to reduce the quantity of elements in an antenna array with a slight alteration in the irradiation pattern applying signal processing techniques. Two synthesis methods are presented: the classical one and the signal processing...

In this paper, we present a description and the complete classification of all (linear and non linear) two-dimensional Lee-perfect Codes. Our results prove that in dimension two the codes constructed by Golomb-Welch [4] are essentially the only ones. We also present a complete description of all possible structures of Lee-perfect two-dimensional codes....

Este artigo investiga o emprego de detectores de voz como uma etapa de pré-processamento de uma técnica de separação cega de sinais implementada no domínio do tempo, que emprega estatísticas de segunda ordem para a separação de misturas convolutivas e determinadas. Seu algoritmo foi adaptado para realizar a separação tanto em banda cheia quanto em...

A circularly polarized microstrip metallic patch antenna made reusing and recycling materials from construction debris is proposed, designed, fabricated and validated in this paper. Such device is used in RFID systems operating at the 902-928MHz UHF band allocated for International Telecommu- nication Union, ITU, Region 2, that includes North and...

Many aproximations are made in the estimation of acoustical fields from measurements obtained with microphone arrays. This article describes a simulator that tries to reproduce in the best way possible a system of acoustic imaging, in order to speed up the evaluation process of approximations and chosen parameters effects in the final quality of...