Gunnar Bedicks

Results of the ISDB-T system tests, as part of digital TV study carried out in Brazil

Since the year 2000, Mackenzie Presbyterian University has been carrying out lab and field tests to evaluate the performance of current DTV systems, with the aim of providing backing for the Brazilian Governments decision on the standard to be adopted. This paper presents the results of tests using the Japanese DTV system ISDB-T. Initially, the tests were done using a first generation prototype of the ISDB-T DTV set-top box. When DTV transmissions began in Japan in November 2003, the Brazilian tests were repeated using several new commercial set-top boxes. The main tests accomplished in 2000 were: measurement of the C/N ratio, behavior of the signal with multipath, Doppler effect and immunity to impulse noise. In 2003/2004, these tests were repeated using new receivers to analyze the evolution of the system. Furthermore, two new tests were introduced: resilience to phase noise and simultaneous transmission of two types of modulation in the same TV channel, in order to evaluate the band segmentation. Also, a one-segment DTV receiver (1STV) in a portable handset was tested in the laboratory.

Re-Multiplexing ISDB-T BTS Into DVB TS for SFN

The Single Frequency Network (SFN) allows a single TV channel to cover a great area in the same frequency, increasing the spectrum efficiency and signal quality. In this case, all the programs are re-multiplexed into a Transport Stream (TS) and distributed to the re-transmitter stations. The Integrated Digital Services Broadcasting-Terrestrial (ISDB-T) has been projected to operate in SFN, and uses a TS-adapted version called Broadcast Transport Stream (BTS). The BTS has a constant bit rate and packet size of 204 bytes. Owing to these characteristics, most network adapters are non compliant with this signal type. This article proposes a new re-multiplexer algorithm of the BTS signal that allows the encapsulation of the BTS into the Digital Video Broadcasting Transport Stream (DVB TS) and vice versa. This technique makes the BTS distribution possible through satellite, allowing the large SFN construction and accomplishing lesser bit rate than the original BTS.

Digital signal disturbed by impulsive noise

This paper presents and comments on test results and measurement procedures carried out mainly in the laboratory to investigate the degree of immunity of DTV reception in the presence of impulse noise. The objective of these tests was to compare the resilience to this type of noise provided by the DTV standards: ATSC, DVB-T and ISDB-T. The field test in the city of Sa/spl tilde/o Paulo, Brazil, showed a high and unforeseen rate of places presenting considerable degradation caused by impulsive noise. Previous studies do not reflect the reality of the impulse noise found in the Brazilian environment. Under these circumstances, a need arises for simulating interference conditions caused by ignition motors, hairdryers, blenders, etc, in the laboratory. Our laboratory tests utilized an impulse noise generator that was constructed especially to emulate ignition noise, but which was shown to be equally satisfactory in emulating other kinds of impulse noise. This paper also describes the operating principles and specifications of the impulse noise generator.

Field trial for Brazilian DTV using space diversity

This paper presents field tests results of High Definition Television (HDTV) mobile reception performance of an Integrated Services Digital Broadcasting-Terrestrial version B (ISDB-TB) receiver with space diversity. The diversity receiver hardware uses a commercial chip with a four branch maximal ratio combining (MRC) system. The tests were performed at the center of the UHF band using 64-QAM in urban, suburban, rural, and highway areas. During the tests the diversity receiver and a standard receiver performances were compared and the results showed that diversity reception would make HDTV mobile reception possible.

Field measurements for ISDB-T B in the VHF band

This paper presents field tests and analysis of the results of the fixed and mobile reception of Integrated Services Digital Broadcasting-Terrestrial version B (ISDB-TB) in the VHF band. A comparative analysis of DTV reception behavior in the VHF and UHF bands is presented.

Performance evaluation of Brazilian DTV mobile reception

This paper presents the tests of Brazilian Digital TV System (SBTVD) carried out to evaluate the performance on mobile reception conditions. The majority of digital television stations in Sao Paulo is configured with hierarchical modulation (one High Definition (HD) program and one Low Definition (LD) program). Considering these two programs, the main areas of São Paulo city area were evaluated and mapped, in order to show the places where the signal needs to be improved.

A proposal to use cloud transmission technique into the ISDB-T system

Cloud Transmission is a new broadcasting system, proposed to be used as the physical layer in the next-generation digital television, especially for the Advanced Television Systems Committee (ATSC) 3.0 system. Its principal benefits are spectral efficiency, robustness against noise, multipath and co-channel interference, besides maintaining compatibility with actual and future systems. Cloud Transmission is based on Layer-Division-Multiplexing (LDM), which provides to the system an increase of its robustness keeping the same data rates. This paper presents a performance analysis of an LDM transmitter/receiver, implemented in Software Defined Radio (SDR), using the same channel coder, interleavers, modulation and OFDM frame structure of Integrated Digital Services Broadcasting-Terrestrial (ISDB-T).

Comparison of Terrestrial DTV Systems: ISDB-TB and DVB-T2 in 6 MHz

The present paper completely discusses the ISDB-TB and the DVB-T2 systems. There are demonstrated the differences and similarities since BTS data entrance to ISDB-TB as well T2-MI to DVB-T2, up to base band generation. Tests for both broadcast television systems have been performed using 6 MHz of bandwidth. The tests procedure in laboratory used TOV (Threshold of Visibility) criteria under different transmissions parameters to ISDB-TB and DVB-T2. It was analyzed the TV interferences as sensibility performance, C/N threshold, Impulsive Noise and Multipath.

ISDB-Tb transmission in software-defined radio

Software-Defined Radio (SDR) has become a great tool for fast prototyping and developing new devices for communications systems as well as for implementing flexible, multi-standards communication equipment. In the same pace, Digital Terrestrial Television Broadcasting (DTTB) has become ubiquitous throughout the world and is continuously in development. Integrated System Digital Broadcasting Terrestrial version B (ISDB-TB) uses Band Segmented Transmission - Orthogonal Frequency Division Multiplexing (BST-OFDM), and a powerful channel code and interleavers. In this article, a new implementation of ISDB-TB modulator with SDR is proposed to achieve real time transmission fully compliant with the ISDB-TB standards. Also the computational performance characteristics of each processing block is presented to compare the total CPU consumption used. The software was developed in the GNU Radio and is a valuable tool in research and educational fields of digital communication.

Nova Ferramenta de Desenvolvimento em Radiodifusão: Software Defined Radio.

Este artigo apresenta uma ferramenta desimulacao do modulador ISDB-TB, que permite realizaranalises complexas em cada estagio de processamento. Apartir de um arquivo Broadcast Transport Stream (BTS) epossivel acompanhar o processamento realizado em cadabloco do modulador ate o estagio final de transmissao.Utilizando um gerador de sinal vetorial e possivel realizartransmissoes reais com os arquivos de RF gerados nosimulador. Uma abordagem matematica e pratica sobre ofuncionamento de cada bloco que constitui o modulador erealizada iniciando pela descricao do sinal BTS ate oestagio final de transmissao.This article will explain some of the general ideas and specific techniques for usingambience in live broadcast audio that the author has developed over the past 30 years in thetelevision industry. The paper is concerned with stereo sound fields. The use of ambiencein a surround matrix is similar in approach, though it of course involves the perspective offront/back in addition to left/right.Este artigo apresenta medidas praticas da area de cobertura de uma emissora de televisao digital experimental da empresa Linear Equipamentos Eletronicos, operando em rede de frequencia unica (Single Frequency Network - SFN) na cidade de Santa Rita do Sapucai, Minas Gerais. O trabalho aborda aspectos teoricos de multiplos sinais resguardados por um prefixo ciclico, a utilizacao de distribuicao de conteudo por satelite, o emprego de enlaces terrestres na faixa de microondas para distribuicao de BTS e as particularidades em se empregar moduladores de diferentes fabricantes.Os receptores de TV Digital terrestre possuem umsoftware de sistema operacional que eventualmente necessita seratualizado pelo fabricante. Alem dos metodos tradicionais viaporta USB, internet, ou atraves das redes de servicos autorizados,surge a possibilidade desta atualizacao ser realizada pelo aratraves do proprio sinal digital que esta sendo recebido, sem anecessidade de intervencao do usuario. O sistema japones de TVDigital, onde o sistema brasileiro esta baseado tambem para aatualizacao de receptores via ar, possui uma entidadecentralizadora que e responsavel por controlar o conteudo detodos os fabricantes e envia-los aos receptores. No Brasil, por naoexistir tal entidade, criou-se um modelo de transmissao onde epossivel que cada emissora seja capaz de gerenciar seu proprioconteudo de download e envia-lo de acordo com o especificadopor cada fabricante. Este trabalho apresenta o estudo realizado,juntamente com o grupo de pesquisas da norma ABNT NBR15603 e os fabricantes de receptores, com a finalidade de definir aestrutura necessaria para cada radiodifusor, de forma a permitirque o envio de dados seja feito de maneira descentralizada e semque haja perdas para o usuario final.Este trabalho pretende continuar a discussao, em nivel teorico, desenvolvida no Congresso Set 2007, sobre o planejamento da grade de programacao em Televisao Digital Interativa. No atual cenario, os emissores tem o desafio de adequar as multiplas possibilidades de producao e distribuicao de conteudo da mais alta tecnologia, para um publico de cultura heterogenea e de contrastes sociais marcantes. Com a digitalizacao, a midia se transforma para alem da experiencia de assistir a uma programacao sequencial e se torna pervasiva, favorecendo, inclusive, o uso de recursos interativos em ambientes moveis e portateis. A televisao, enfim, adquire o status tecnologico que possibilita sua definitiva integracao ao ciberespaco, levando consigo, pela usabilidade, pelo entretenimento e pelo sentido de comunhao, a parcela da populacao que o computador, sozinho, nao alcanca. Contudo, a questao mais relevante, no processo de convergencia, esta na constituicao de uma grade que mantenha seu foco nas experiencias genuinamente televisivas. Aquelas que estimulam a interacao social, do publico entre si e com o assunto em pauta. O HDTV aumenta o prazer compartilhado de assistir televisao em casa. Os dispositivos moveis sao digitais e seus usuarios, interativos. Nesse cenario, tem muito a ganhar a programacao que souber conciliar a liberdade individual de escolhas com a satisfacao da experiencia comum, que primeiro estabelecer seus paradigmas “televisivos” de interacao com o publico.Com o advento do Sistema Brasileiro de TV Digital (SBTVD), e tendo em conta osseus recursos de universalizacao previstos no cronograma de implantacao, umagrande variedade de tecnologias de displays (incluindo receptores de altaresolucao, displays de celulares, etc.) ira requerer ensaios de resposta e defidedignidade colorimetrica para a adequada insercao no mercado brasileiro.Neste contexto, e importante destacar que a qualidade da resposta cromatica, naotica do telespectador, depende nao somente da adequacao dos parâmetros doSistema transmissor, mas tambem do desempenho dos displays (modernosdisplays planos ou Flat Panel Displays -FPD), dos efeitos de distorcoes em corproduzidas por nao linearidades nos set-top box e outros dispositivos detratamento de sinal de video.De uma maneira geral, a questao da fidelidade da resposta cromatica de displaysextrapola questoes ou elementos de apreciacao puramente subjetiva (qualidadeda resposta de um receptor de TV), assumindo cada vez mais relevância nomundo moderno a associacao das coordenadas de cor do elemento cromatico dodisplay a um dado mensurando: na area da saude, as cores apresentadas nosdisplays estao relacionadas a diagnosticos; no campo da ciencia, o espectrocromatico esta associado, cada vez de forma mais ampla, a novos mensurandos(altitude, temperatura, pressao, vazao, tipo de vegetacao, caracteristicasgeologicas, etc.).O objetivo deste trabalho e apresentar os testes a serem adotadas pelo CPqD eDIOPT/Inmetro no sentido de efetuar a caracterizacao de FPDs, em conformidadecom normas e recomendacoes internacionais e cadeias de rastreabilidadeenvolvidas.Este artigo apresenta um estudo de obras audiovisuais que utilizam a interatividade em sua narrativa, os chamados videos interativos, presentes na web e em DVD. Desenvolve uma discussao sobre as diferencas entre interacao e interatividade em videos interativos. Estabelece uma classificacao em modalidades das formas interativas em audiovisualEste trabalho pretende apresentar uma metodologia para mensuracao das degradacoes sofridas pelo sinal de video quando e transportado por redes IP....