No description available.

No description available.

Page 139 not included in the thesis. / <p> The problem of coherent carrier recovery and the effects of phase error on the performance of an offset quadrature-phase-shift-keying (QPSK) duobinary system have been investigated in the thesis. The system of interest is similar to RD -3 digital system that is being developed and installed as an efficient high data-rate digital radio communication system by Bell Northern Research Laboratory (BNR). </p> <p> Four carrier regeneration loop structures are investigated and analysed in the thesis. These are: (i) estimate-aided suppressed carrier loop (ii) decision-directed feedback loop (iii) shifted decision-directed feedback loop (iv) half-shifted decision-directed feedback loop All of these loop structures employ the technique of data-aided carrier synchronization. The estimate-aided loop structure exhibits steadystate behavior similar to that of a conventional Costas loop. The remaining three loop structures differ from the estimate-aided loop in the sense that they require decisions to make on the noisy received signal. These are then fedback to the carrier recovery circuit in such a way as to create a spectral line at carrier frequency. The loop behavior in the presence of additive noise has been investigated in some detail. For each loop, analytical expressions for the phase detector characteristic (S-curve) and the steady-state phase error probability density function (pdf) are derived, and provide a means of comparing the performance of the different recovery schemes.</p> / Thesis / Master of Engineering (MEngr)

In this thesis a Fully-Photonic DRoF (FP-DRoF) system is proposed for deploying of future super-broadband access networks. Digital Radio over Fibre (DRoF) is more independent of the fibre network impairments and the length of fibre than the ARoF link. In order for fully optical deployment of the signal conversion techniques in the FP-DRoF architecture, two key components an Analogue-to-Digital Converter (ADC) and a Digital-to-Analogue Converter (DAC)) for data conversion are designed and their performance are investigated whereas the physical functionality is evaluated. The system simulation results of the proposed pipelined Photonic ADC (PADC) show that the PADC has 10 GHz bandwidth around 60 GHz of sampling rate. Furthermore, by changing the bandwidth of the optical bandpass filter, switching to another band of sampling frequency provides optimised performance condition of the PADC. The PADC has low changes on the Effective Number of Bit (ENOB) response versus analogue RF input from 1 GHz up to 22 GHz for 60 GHz sampling frequency. The proposed 8-Bit pipelined PADC performance in terms of ENOB is evaluated at 60 Gigasample/s which is about 4.1. Recently, different methods have been reported by researchers to implement Photonic DACs (PDACs), but their aim was to convert digital electrical signals to the corresponding analogue signal by assisting the optical techniques. In this thesis, a Binary Weighted PDAC (BW-PDAC) is proposed. In this BW-PDAC, optical digital signals are fully optically converted to an analogue signal. The spurious free dynamic range at the output of the PDAC in a back-to-back deployment of the PADC and the PDAC was 26.6 dBc. For further improvement in the system performance, a 3R (Retiming, Reshaping and Reamplifying) regeneration system is proposed in this thesis. Simulation results show that for an ultrashort RZ pulse with a 5% duty cycle at 65 Gbit/s using the proposed 3R regeneration system on a link reduces rms timing jitter by 90% while the regenerated pulse eye opening height is improved by 65%. Finally, in this thesis the proposed FP-DRoF functionality is evaluated whereas its performance is investigated through a dedicated and shared fibre links. The simulation results show (in the case of low level signal to noise ratio, in comparison with ARoF through a dedicated fibre link) that the FP-DRoF has better BER performance than the ARoF in the order of 10-20. Furthermore, in order to realize a BER about 10-25 for the ARoF, the power penalty is about 4 dBm higher than the FP-DRoF link. The simulation results demonstrate that by considering 0.2 dB/km attenuation of a standard single mode fibre, the dedicated fibre length for the FP-DRoF link can be increased to about 20 km more than the ARoF link. Moreover, for performance assessment of the proposed FP-DRoF in a shared fibre link, the BER of the FP-DRoF link is about 10-10 magnitude less than the ARoF link for -19 dBm launched power into the fibre and the power penalty of the ARoF system is 10 dBm more than the FP-DRoF link. It is significant to increase the fibre link’s length of the FP-DRoF access network using common infrastructure. In addition, the simulation results are demonstrated that the FP-DRoF with non-uniform Wavelength Division Multiplexing (WDM) is more robust against four wave mixing impairment than the conventional WDM technique with uniform wavelength allocation and has better performance in terms of BER. It is clearly verified that the lunched power penalty at CS for DRoF link with uniform WDM techniques is about 2 dB higher than non-uniform WDM technique. Furthermore, uniform WDM method requires more bandwidth than non-uniform scheme which depends on the total number of channels and channels spacing.

[pt] Este trabalho teve como objetivo o levantamento de parâmetros para o auxílio no cálculo de desempenho e dimensionamento de sistemas digitais terrestres. Estes parâmetros forma obtidos através de medidas em enlaces analógicos pertencentes a Empresa Brasileira de telecomunicações e a Telesc, espalhados por todo o Brasil. Toda estrutura necessária para obtenção destes dados foi desenvolvida no CETUC. As principais características dos sistemas experimentais de medidas, programas para análise de dados, bem como uma descrição detalhada dos experimentos são apresentadas neste trabalho. Os resultados principais apresentados são as análises estatísticas de parâmetros de propagação em condições de céu claro. Nestes resultados estão incluídos as distribuições anuais, pior mês, desvanecimentos máximos e retardo. Os resultados obtidos foram também usados para avaliação de performance de alguns enlaces digitais. / [en] The aim this work was to obtain design parameters for terrestrial digital systems, and to Access their reliability and quality. These design parameters were obtained from measurements made in analogic links operated by the Brazilian telecommunication company Telebrás and Telesc, localised throughout Brazil.The techniques necessary to obtain the data were developed at CETUC. The main characteristcs of experimental links used in this work are presented, as well as the software used for the analyses. A complete description of the experimental set-up is also presented. The main results are the statistical analyses of the propagation parameters for cleae sky. Thes eresults include the annual attenuation, worst month attenuation, relative delay and maximum fading distributions. The results obtained were also used for performance evaluation of some digital links.

[pt] Em 2010, o Ministro das Comunicações instituiu o Sistema Brasileiro de Rádio Digital (SBRD). No entanto, um modelo de referência para o sistema ainda não foi definido. Este trabalho apresenta uma análise da radiodifusão sonora terrestre no Brasil e a partir desta são inferidos alguns requisitos para um rádio digital interativo. Esses requisitos são então utilizados para nortear a pesquisa. A relevância e importância do uso da NCL e do Ginga no rádio digital brasileiro, assim como acontece no Sistema Brasileiro de TV Digital (SBTVD), são discutidas, e a definição da forma como deve ser feito o transporte de aplicações NCL nos dois sistemas de rádio digital sendo considerados para adoção pelo país é realizada. Um novo perfil da linguagem NCL para o rádio digital é definido. Esse novo perfil recebeu o nome de perfil Digital Radio, ou simplesmente DR. O Ginga também é definido para uso em receptores de rádio digital, sendo que novos exibidores de mídia e recursos adaptados ao contexto do rádio digital são introduzidos. A implementação do Ginga da PUC-Rio é apresentada com as modificações necessárias para o rádio digital. Adicionalmente, um ambiente para validar a interatividade no rádio digital com o Ginga foi montado e testes exercitando toda a cadeia de transmissão e recepção de rádio digital com aplicações NCL embutidas foram realizados. As definições e conclusões que resultaram da pesquisa visam contribuir para a definição de um Sistema Brasileiro de Rádio Digital que seja poderoso em termos comunicacionais e agregue os recursos mais relevantes para o meio na era digital. / [en] In 2010, the Minister of Communications instituted the Brazilian Digital Radio System (SBRD), however a reference model for the system has not yet been set. This text presents an analysis of the terrestrial radio broadcasting in Brazil and presents some requirements for an interactive digital radio. These requirements are then used to guide the research. The relevance and importance of the use of NCL and Ginga in the Brazilian digital radio as in Brazilian Digital TV System (SBTVD), are discussed, and the definition of how the transport of NCL applications should be done in the two digital radio systems being considered for adoption by the country is performed. A new profile of NCL for use in digital radio is defined. This new profile was named Digital Radio Profile, or just DR. Ginga is also defined for use in digital radio receivers, and new media players and features adapted to the digital radio context are introduced. PUC-Rio s implementation of the Ginga middleware is presented with the necessary modifications for digital radio use. In addition, an environment to validate the interactivity in digital radio with the Ginga was assembled and tests exercising the entire digital radio chain of transmission and reception with embedded NCL applications were performed. The definitions and conclusions that resulted from research activities are expected to contribute to the definition of a Brazilian Digital Radio System that is powerful in communicational terms and aggregates the most relevant technologies for the medium in the digital age.

On 29th February 2000, The Directorate General of Telecommunications, Ministry of Transportation and Communications, announced the result of selection for DAB (Digital Audio Broadcasting) experimental digital broadcasting. From that moment, many FM Radio Stations initiated their DAB digital broadcasting. Compared with FM Radio, AM Radio is slower on initiating digital broadcasting. However, new technology continuously comes out. The integration of media technology has a great influence on the media broadcasting model. The emergence of new media accelerates the decline of traditional media. Earlier emerging than internet, TV and FM Radio industries, how will AM Radio strive for continuance and development? To encourage existing AM Radio in initiating their digital future, the Ministry of Transportation and Communications announced the project of experimental digital broadcasting of IBOC AM and DRM on June 3rd, 2004. It is worth for the research scholars to study how the AM Radio initiates digital broadcasting and what the influential factors are. Therefore, this research is trying to find the factors which turn AM Radio to the digital future, and also discuss what factors will encourage radio enterprenors to initiate digital broadcasting, what kind of digital system is appropriate for AM Radio, and what the situation is for experimental DRM broadcasting in Taiwan. We are trying to find out the factors turning AM Radio to the digital future, and make AM Radio (with declining listening ratio and poor reception quality) improve the performance, as well as create new core value of AM Radio Industry. According to the objective and motivation above-mentioned, we designed and proceeded this research as follows: We started from an investigation on 28 AM Radio Stations in Taiwan to know their needs for digital broadcasting, and then collected data and made statistic analysis based on the questionnaires returned. We also took interviews with professional people assisting in DRM digital broadcasting for AM Radio. Besides, we participated in the World DAB Forum Conference held in Taiwan in this year, and finally went into a conclusion and some suggestions. We found from the information in questionnaires that the factors making AM Radio to initiate digital broadcasting are not precise. However, we know more about how the digital broadcasting is going among AM Radio Stations, from the information collected by interviewing professional people who assist in DRM digital broadcasting for AM Radio. It will bring advantages in competition for AM Radio Stations to initiate digital broadcasting. Thus, it can not wait to turn to digital future. The Radio enterprenors should use technology well and increase additional value. They have to follow the trend, develop new co-operation model, and establish their brand image. They should also enhance on inspection of program contents, and hold success factors. They can increase reception ratio only with fine broadcasting, excellent program contents, good reception quality and perfect marketing strategy. As to the technical people, they need to care about the development on technology, and provide new information for management to make decision. Besides, the policy of government must be precise, in order to encourage Radio enterprenors in initiating digital broadcasting. The above conclusion could be the reference in digital radio research.

[pt] Um método, baseado no conceito de assinatura, foi desenvolvido para avaliar a influência da separação vertical entre as antenas na melhoria introduzida pala diversidade em espaço nos Sistemas Rádio Digitais. Para esta análise foram utilizadas estatísticas de desvanecimentos seletivos, medidos em enlaces radiovisibilidade no Brasil. Os resultados revelam a existência de uma separação ótima. Também é apresentado um método do estimativo para o cálculo da melhoria deste tipo de diversidade em espaço. / [en] A method base don the concept of signature for analysis of the improvement related to vertical antenna separation on digital radio with space diversity was developed. The analysis was performed on selective fading statistics obtained from measurements in LOS links in Brazil. The results reveal the existence of an optimum antenna separation. Also, a prediction method for evaluating this type of diversity improvement is presented.

[pt] Este trabalho examina os novos sistemas de transmissão, fibra ótica e rádio digital, sob o ponto de vista de sistema, procurando discutir métodos e sugerir critérios para o projeto e dimensionamento de enlaces. O trabalho inclui uma abordagem dos conceitos básicos, bem como uma análise de questões operacionais e econômicas existentes na aplicação a entroncamentos urbanos. / [en] This work analyses moderns transmission systems, optical fiber and digital radio, with the objectives to discuss methods and to suggest criterios for planning and design of radiolinks. The work contains basic concepts as well as operational and economic questions for urban conections.

[pt] Recentemente, a UIT aprovou a recomendação G.826 que estabelece os padrões de desempenho dos enlaces digitais operando na ou acima da taxa de 64Kbits/s. Esta recomendação introduz novos conceitos e parâmetros de desempenho cujo impacto no dimensionamento de enlaces está ainda em processo de avaliação. É desenvolvida neste desenvolvida neste trabalho uma modelagem probabilística através da qual é feita uma análise dos parâmetros de desempenho da Recomendação G.826. O resultado desta análise é em seguida utilizado para estabelecer uma metodologia de dimensionamento de enlaces sujeitos a desvanecimento plano e seletivo, que é o caso típico de enlaces rádio digitais de alta capacidade. Esta metodologia é comparada com a que vem sendo elaborado no âmbito do grupo IX da UIT. / [en] Recently the ITU has approved the Recommendation G.826 that specified the performance of the physical layer of new broadband digital services. This recommendation has introduced new error performance parameters whose impact in the sytem design is still being evaluated. In this work a probabilistic model to analyse the G.826 error performance parameters is developed. These results are used to establish a new methodology for digital radio link design subject to flat or selective fading. Finally this metodology is compared with the one elaborated by Study Group IX of ITU-R.