Clock and data recovery (CDR) circuit and frequency synthesizer are two essential timing circuits in wireline and wireless communication systems, respectively. With multigigabits/s high speed links and emerging 4G wireless system widely used in communication backbone infrastructures and consumer electronic devices, effective design of CDR and frequency synthesizer has become more and more important. The advanced scaled-down CMOS process has the limitations of leakage current, low supply voltage and process variation which pose great challenge to the analog circuit design. To overcome these issues, a digital intensive CDR solution is needed. Besides, it is desirable for the CDR to cover a wide range of data-rate and to be reference-less for improved flexibility. As for the frequency synthesizer design, the support for multi-standard to reduce the cost and area is desirable. In this work, a digital reference-less CDR is proposed to support continuous datarate ranging from 1 Gbps to 16 Gbps. The CDR adopts an 8 GHz~16 GHz DCO to achieve low random noise performance. A reference-less digital frequency locking loop is included in the system as the acquisition assistance for the CDR loop. To address the difficulty of jitter and stability evaluations for bang-band CDR, a Simulink model is developed to find out the jitter transfer (JTRAN), jitter generation (JGEN) and jitter tolerance (JTOL) performances for the CDR. The prototype CDR is implemented in a 65 nm CMOS process. The core area is 0.68 mm². At 16 Gbps, the CDR consumes a power of 92.5 mW and is able to tolerate a sinusoidal jitter with an amplitude of 0.4 UI and a frequency of 4 MHz. The second part of this dissertation develops a frequency synthesizer for multistandard wireless receivers. The frequency synthesizer is based on an analog fractional-N PLL. Optimally-coupled quadrature voltage-controlled-oscillator (QVCO), dividers and harmonic rejection single sideband mixer (HR-SSBmixer) are combined to synthesize the desired frequency range without posing much phase noise penalty on the QVCO. The QVCO adopts a new phase-shift scheme to improve phase noise and to eliminate bimodal oscillation. Combining harmonic rejection and single sideband mixing, the HR-SSBmixer is developed to suppress spurious signals. Designed in a 0.13-μm CMOS technology, the synthesizer occupies an active area of 1.86 mm² and consumes 35.6 to 52.62 mW of power. Measurement results show that the synthesizer frequency range, the phase noise, the settling time and the spur performances meet the specifications of the wireless receivers for the above standards. For a wide range frequency synthesizer, an automatic frequency calibration circuit (AFC) is needed to select proper oscillator tuning curve before the PLL settling. An improved counter-based AFC is proposed in this dissertation that provides a more robust and faster tuning curve searching process. The proposed AFC adopts a time-to-digital converter (TDC), which is able to captures the fractional VCO cycle information within the counting window, to improve the AFC frequency detection accuracy. The TDC-based AFC is designed in a 0.13-μm CMOS technology. Simulation results show that the TDCbased AFC greatly improves the frequency detection accuracy and consequently for a given frequency detection resolution reduces the AFC calibration time.

In the education process of the elder students (of 8 – 12 classes) of the secondary school the pedagogical activity is to be oriehted to the needs of the needs of the student, upbringing of creative abilities improvising on the music lessons, capability to adopt the modern digital technologies in various self-expression areas. Namely the lack of digital technologies influences the little interest of students for music lesson: it conditions the passivity and causes the problems of discipline. The object of research is formation of creative activity of student of secondary school using digital technologies on music lessons. Objective is to reveal the importance of introduction of musical improvisations and particularities of creation by students using digital technologies, also forming the positive and active attitude of students towards the taught subject of music. Hypothesis is raised that if the synthesizer, computer and other digital technologies are used on music lesson in order to develop the creative activity of the student then the attitude of students toward subject of music will become more motivated, the musical subject will become more motivated, the musical subject will assume more attractiveness. The methods of theoretical, empirical and mathematical analysis are used in this work. The descriptive research was performed in the Dzukijos secondary school of Alytus. 226 students (of 8 – 12 classes) and teachers of music of secondary schools from Alytus city and... [to full text]

The main purpose of this dissertation was to address key issues in the design and analysis of RF/microwave filters for wireless applications. Since RF/microwave filters are one of the bulkiest parts of communication systems, their miniaturization is one of the most important technological challenges for the development of compact transceivers. In this work, novel miniaturization techniques were investigated for single-band, dual-band, ultra-wideband and tunable bandpass filters. In single-band filters, the use of cross-shaped fractals in half-mode substrate-integrated-waveguide bandpass filters resulted in a 37 percent size reduction. A compact bandpass filter that occupies an area of 0.315 mm2 is implemented in 90-nm CMOS technology for 20 GHz applications. For dual-band filters, using half-mode substrate-integrated-waveguides resulted in a filter that is six times smaller than its full-mode counterpart. For ultra-wideband filters, using slow-wave capacitively-loaded coplanar-waveguides resulted in a filter with improved stopband performance and frequency notch, while being 25 percent smaller in size. A major part of this work also dealt with the concept of 'hybrid' RF MEMS tunable filters where packaged, off-the-shelf RF MEMS switches were used to implement high-performance tunable filters using substrate-integrated-waveguide technology. These 'hybrid' filters are very easily fabricated compared to current state-of-the-art RF MEMS tunable filters because they do not require a clean-room facility. Both the full-mode and half-mode substrate-integrated waveguide tunable filters reported in this work have the best Q-factors (93 - 132 and 75 - 140, respectively) compared to any 'hybrid' RF MEMS tunable filter reported in current literature. Also, the half-mode substrate-integrated waveguide tunable filter is 2.5 times smaller than its full-mode counterpart while having similar performance. This dissertation also presented detailed analytical and simulation-based studies of nonlinear noise phenomena induced by Brownian motion in all-pole RF MEMS tunable filters. Two independent mathematical methods are proposed to calculate phase noise in RF MEMS tunable filters: (1) pole-perturbation approach, and (2) admittance-approach. These methods are compared to each other and to harmonic balance noise simulations using the CAD-model of the RF MEMS switch. To account for the switch nonlinearity in the mathematical methods, a nonlinear nodal analysis technique for tunable filters is also presented. In summary, it is shown that output signal-to-noise ratio degradation due to Brownian motion is maximum for low fractional bandwidth, high order and high quality factor RF MEMS tunable filters. Finally, a self-sustained microwave platform to detect the dielectric constant of organic liquids is presented in this dissertation. The main idea is to use a voltage- controlled negative-resistance oscillator whose frequency of oscillation varies according to the organic liquid under test. To make the system self-sustained, the oscillator is embedded in a frequency synthesizer system, which is then digitally interfaced to a computer for calculation of dielectric constant. Such a system has potential uses in a variety of applications in medicine, agriculture and pharmaceuticals.

Thesis (M.M.)--The University of North Carolina at Greensboro, 2008. / Directed by Mark Engebretson; submitted to the School of Music. Title from PDF t.p. (viewed Aug. 27, 2009). Includes bibliographical references (p. 30-31).

Este trabalho apresenta uma proposta de sistema para permitir o acesso à informações numa estrutura baseada em sistemas computacionais, visando monitoramento remoto. Desta forma, pessoas responsáveis por um ambiente eletronicamente monitorado poderão coletar informações em um ambiente computacional através de telefonia IP, síntese de voz e integração com a rede de telefonia pública comutada, obter informações passivamente ou ativamente de uma estrutura monitorada. Os recursos sugeridos para esse modelo proposto foram escolhidas conforme sua utilização no mercado, ou facilidade na aplicação prática. Sempre que possível, usando software livre (Open Source), de tal forma que o formato apresentado neste trabalho possa fomentar outros estudos e ser utilizado para soluções mais sofisticadas. É possível, também, haver aplicações relacionadas com a acessibilidade para deficientes visuais. Sistemas proprietários para acesso a informações remotas estão cada vez mais comuns, especialmente em soluções corporativas, porém acesso a informações através de voz não é uma prática comum. Sabendo que a telefonia cada vez se torna mais acessível e comum de ser acessada de qualquer local, é possível coletar informações em um sistema eletrônico, transformando-as em frases parametrizada e posteriormente, reproduzidas por um sistema computacional. Foram realizados ensaios práticos do sistema proposto com os elementos básicos de funcionamento. Os resultados apresentados foram satisfatórios e indicam que aplicações deste modelo podem ser realizadas em diversas estruturas, observando as adequações para cada uma delas. / This work presents a proposed system for accessing information in structure-based computer systems, aiming at remote monitoring. Persons responsible for an electronically monitored environment may collect information in a computer environment and through IP telephony, voice synthesis and integration with the PSTN (Public Switched Telephone Network), obtain information passively or actively from a monitored environment. The resources suggested for this model were chosen according to their use in the market or facility in practice. Whenever possible, using Open Source software, so that the format presented in this work could stimulate further studies and be used for more sophisticated solutions. You can also have applications related to accessibility for the visually impaired people. Proprietary systems for remote access to information are increasingly common, especially in enterprise solutions, but to access information through voice is not a common practice. Knowing that the phone becomes ever more accessible and common to be accessed from anywhere, it is possible to collect information in an electronic system, transforming them into sentences parameterized and subsequently reproduced by a computer system. Tests with the basic elements of operation were performed. The results were satisfactory and indicate that applications of this model can be realized in various structures, observing the adjustments for each one.

Sintetizadores de Freqüências são circuitos que geram sinais em freqüências pré-determinadas, sendo estes sinais usados tanto na recepção como na transmissão de Rádio Freqüência. Os circuitos Sintetizadores possuem diversos blocos, dentre os quais podemos citar, osciladores controlados por tensão (VCO Voltage-Controlled Oscillator), divisores programáveis (Prescaler), comparadores de fase (DFF Detectores de Fase e Freqüência), bombas de carga (CP Charge Pump) e Filtros Passa Baixas (LPF Low Pass Filters). Em 2003 foi projetado por Angel M.G. Argüello [Ar04] um circuito Sintetizador de Freqüências com arquitetura tipo Integer-N. Este circuito, projetado para ter banda centrada em torno de 2,4 GHz e 16 canais de 4,78 MHz, foi implementado na tecnologia CMOS 0,35 µm da AMS (Austrian Micro Systems), que possui quatro níveis de metais e dois níveis de polisilício. Após testes do circuito as seguintes conclusões sobre seu funcionamento foram derivadas: o circuito funcionou qualitativamente como projetado, sintetizando 16 tons de freqüência; o ruído de fase medido ficou acima do valor desejado; a potência consumida esteve dentro dos valores previstos, porém elevada. No decorrer de 2004 foram feitas alterações no layout do circuito de Argüello com o objetivo de melhorar o ruído de fase. Estas alterações serviram como estudo preliminar para este trabalho. Dando continuidade ao desenvolvimento de Sintetizadores, em 2005 foram estudadas novas estruturas e layouts mais eficientes no tocante a ruído de fase, dando-se especial atenção às alimentações dos circuitos digitais e analógicos e ao isolamento entre os mesmos. Um novo circuito Sintetizador foi desenvolvido para aplicações em sistemas ZigBee, que operam na banda de freqüência entre 2,400 GHz a 2,485 GHz, com 16 canais de largura igual 2 à 5 MHz. Resultados de simulação sobre o circuito projetado apontaram o funcionamento adequado, com consumo de potência inferior a 32 mW para tensão de alimentação de 3,3 V. / Frequency Synthesizers are circuits that generate pre-determined frequencies, used in both radio frequency reception and transmission. The Synthesizer circuits are composed by several blocks, such as Voltage-Controlled Oscillator (VCO), Prescaler, PFD (Phase/Frequency Detector), Charge Pump (CP), and Low Pass Filters (LPF). In 2003, an Integer-N architecture Frequency Synthesizer circuit was developed by Angel M.G. Argüello [Ar04]. This circuit, designed to have a band centered around 2.4 GHz and 16 channels with a 4.78 MHz, were implemented with the 0.35 µm CMOS technology from AMS (Austrian Micro Systems), using four metal levels and two polisilicon levels. After the circuit tests, the following conclusions about its operation were derived: the designed circuit operated as expected, generating 16 tons of frequency; the phase noise stayed above of the desired value; the power consumption were within the expected values although high. During the year of 2004, several modifications in the Argüello circuit layout have been done in order to improve the phase noise. These modifications were a preliminary study to this work. Advancing in the development of Synthesizers, in 2005 new structures and more efficient layouts, in terms of noise, were studied, with special attention given to the digital and analog power supplies and their isolation. A new Synthesizer was developed for applications with the ZigBee, which operates with frequencies from 2.400 GHz to 2.485 GHz and 16 channels of 5 MHz. The simulation results pointed out the correct operation of the circuit, with power consumption lower than 32 mW for power supply of 3.3 V.

This thesis traces the history and development of the facilities for electronic music in the UK. It covers the early attempts to experiment with electronic music and create studios in less than ideal circumstances and the subsequent bids to create a national centre. It also covers some elements of worldwide development of electronic music and sound recording, in particular those which occurred before 1965. The thesis calls upon non-traditional sources and the author was able to access many documents in the personal archives of electronic music pioneers. There is substantial reference to committees and societies for electronic music and their effects on the development of facilities for electronic music in the UK. Some of the early pioneers are studied in detail; these include Daphne Oram, Tristram Cary and Hugh Davies. Unprecedented access to information on Hugh Davies and Daphne Oram was provided by the family estates of these recently deceased composers. This allowed the author to gain valuable insight into the working patterns and methodology of these composers. Many references to later pioneers such as Trevor Wishart are also made but the focus remains on the facilities available to composers rather than the composers and their works.

This thesis in computer science aimed to evaluate the suitability of the Web Audio API to implement virtual analog synthesizers. In order to do so a method for producing a reference architecture for analog synthesizers and a categorization and point system for the evaluation were developed. A reference architecture were made and then implemented with the API and the evaluation were then made based on that implementation. The API were found to cover a lot of the necessary areas, but lacking in a few key components; a noise generator, a native way to automate custom numeric properties and the implementation of the oscillator were deemed too closed to support all use cases.

Speech sounds generated by a simple waveform synthesizer were used to create a vector quantization codebook for use in speech recognition. Recognition was tested over the TI-20 isolated word data base using a conventional DTW matching algorithm. Input speech was band limited to 300 - 3300 Hz, then passed through the Scott Instruments Corp. Coretechs process, implemented on a VET3 speech terminal, to create the speech representation for matching. Synthesized sounds were processed in software by a VET3 signal processing emulation program. Emulation and recognition were performed on a DEC VAX 11/750. The experiments were organized in 2 series. A preliminary experiment, using no vector quantization, provided a baseline for comparison. The original codebook contained 109 vectors, all derived from 2 formant synthesized sounds. This codebook was decimated through the course of the first series of experiments, based on the number of times each vector was used in quantizing the training data for the previous experiment, in order to determine the smallest subset of vectors suitable for coding the speech data base. The second series of experiments altered several test conditions in order to evaluate the applicability of the minimal synthesized codebook to conventional codebook training. The baseline recognition rate was 97%. The recognition rate for synthesized codebooks was approximately 92% for sizes ranging from 109 to 16 vectors. Accuracy for smaller codebooks was slightly less than 90%. Error analysis showed that the primary loss in dropping below 16 vectors was in coding of voiced sounds with high frequency second formants. The 16 vector synthesized codebook was chosen as the seed for the second series of experiments. After one training iteration, and using a normalized distortion score, trained codebooks performed with an accuracy of 95.1%. When codebooks were trained and tested on different sets of speakers, accuracy was 94.9%, indicating that very little speaker dependence was introduced by the training.

The aim of this work is to design digital synthesizer and modulator on embedded sys- tems. Work is exploring existing digital synthesizer and modulators in embedded systems and PC and with that gained knowledge is presenting possible solution of design on Field Programmable Gate Array.