Referenced Approximation Technique for a Rom-Less Sweep Frequency Synthesizer

The main goal of this paper is to present a novel ROM-less direct digital frequency synthesizer for sweep instrumentation systems. It provides a main sweep channel for frequency analysis and a reference channel for phase and amplitude measurement block operating at constant frequency. For phase to amplitude converter, we propose a new trigonometric approximation technique based on a set of reference angles. In addition, we present the design of the proposed synthesizer and its evaluation in Matlab-Simulink environment. The simulation results illustrate the performances and demonstrate the effectiveness of our proposed circuit

Transmitter architectures with digital modulators, D/A converters and switching-mode power amplifiers

This thesis is composed of nine publications and an overview of the research topic, which also summarises the work. The research described in this thesis focuses on research into the digitalisation of wireless communication base station transmitters. In particular it has three foci: digital modulation, D/A conversion and switching-mode power amplification. The main interest in the implementation of these circuits is in CMOS. The work summarizes the designs of several circuit blocks of a wireless transmitter base station. In the baseband stage, a multicarrier digital modulator that combines multiple modulated signals at different carrier frequencies digitally at baseband, and a multimode digital modulator that can be operated for three different communications standards, are implemented as integrated circuits. The digital modulators include digital power ramping and power level control units for transmission bursts. The upconversion of the baseband signal is implemented using an integrated digital quadrature modulator. The work presented provides insight into the digital-to-analogue interface in the transmitters. This interface is studied both by implementing an intermediate frequency D/A converter in BiCMOS technology and bandpass Delta-Sigma modulator-based D/A conversion in CMOS technology. Finally, the last part of the work discusses switching-mode power amplifiers which are experimented with both as discrete and integrated implementations in conjunction with 1-bit Delta-Sigma modulation and pulse-width modulation as input signal generation methods.Tämä väitöskirja koostuu yhdeksästä julkaisusta ja tutkimusaiheen yhteenvedosta. Väitöskirjassa esitetty tutkimus keskittyy langattaman viestinnän tukiasemien lähettimien digitalisoinnin tutkimukseen. Yksityiskohtaisemmin tutkimusalueet ovat: digitaalinen modulaatio, D/A muunnos ja kytkinmuotoiset tehovahvistimet. Näiden elektronisten piirien toteutuksessa keskitytään CMOS teknologiaan. Työ vetää yhteen useiden langattoman viestinnän tukiasemien lähettimien piirilohkojen suunnittelun. Kantataajuusasteella toteutetaan integroituna piirinä monikantoaaltoinen digitaalinen modulaattori, joka yhdistää useita moduloituja signaaleja eri kantoaalloilla digitaalisesti ja monistandardi digitaalinen modulaatori, joka tukee kolmea eri viestintästandardia. Digitaaliset modulaattoripiirit sisältävät digitaalisen tehoramping ja tehotason säätöyksikön lähetyspurskeita varten. Kantataajuussignaalin ylössekoitus toteutetaan integroitua digitaalista kvadratuurimodulaattoria käyttäen. Esitetty työ antaa näkemystä lähettimien digitalia-analogia rajapintaan, jota tutkitaan toteuttamalla välitaajuinen D/A muunnin BiCMOS teknologialla ja päästökaistainen Delta-Sigma-modulaattoripohjainen D/A muunnin CMOS teknologialla. Lopuksi työn viimeinen osa käsittelee kytkinmuotoisia tehovahvistimia, joita tutkitaan kokeellisesti sekä erilliskompontein toteutettuina piirein että integroiduin piirein toteutettuina käyttäen sisääntulosignaalin muodostamismenetemänä yksibittistä Delta-Sigma-modulaatiota ja pulssin leveys modulaatiota.reviewe

Transceiver architectures and sub-mW fast frequency-hopping synthesizers for ultra-low power WSNs

Wireless sensor networks (WSN) have the potential to become the third wireless revolution after wireless voice networks in the 80s and wireless data networks in the late 90s. This revolution will finally connect together the physical world of the human and the virtual world of the electronic devices. Though in the recent years large progress in power consumption reduction has been made in the wireless arena in order to increase the battery life, this is still not enough to achieve a wide adoption of this technology. Indeed, while nowadays consumers are used to charge batteries in laptops, mobile phones and other high-tech products, this operation becomes infeasible when scaled up to large industrial, enterprise or home networks composed of thousands of wireless nodes. Wireless sensor networks come as a new way to connect electronic equipments reducing, in this way, the costs associated with the installation and maintenance of large wired networks. To accomplish this task, it is necessary to reduce the energy consumption of the wireless node to a point where energy harvesting becomes feasible and the node energy autonomy exceeds the life time of the wireless node itself. This thesis focuses on the radio design, which is the backbone of any wireless node. A common approach to radio design for WSNs is to start from a very simple radio (like an RFID) adding more functionalities up to the point in which the power budget is reached. In this way, the robustness of the wireless link is traded off for power reducing the range of applications that can draw benefit form a WSN. In this thesis, we propose a novel approach to the radio design for WSNs. We started from a proven architecture like Bluetooth, and progressively we removed all the functionalities that are not required for WSNs. The robustness of the wireless link is guaranteed by using a fast frequency hopping spread spectrum technique while the power budget is achieved by optimizing the radio architecture and the frequency hopping synthesizer Two different radio architectures and a novel fast frequency hopping synthesizer are proposed that cover the large space of applications for WSNs. The two architectures make use of the peculiarities of each scenario and, together with a novel fast frequency hopping synthesizer, proved that spread spectrum techniques can be used also in severely power constrained scenarios like WSNs. This solution opens a new window toward a radio design, which ultimately trades off flexibility, rather than robustness, for power consumption. In this way, we broadened the range of applications for WSNs to areas in which security and reliability of the communication link are mandatory

Hardward and algorithm architectures for real-time additive synthesis

Additive synthesis is a fundamental computer music synthesis paradigm tracing its origins to the work of Fourier and Helmholtz. Rudimentary implementation linearly combines harmonic sinusoids (or partials) to generate tones whose perceived timbral characteristics are a strong function of the partial amplitude spectrum. Having evolved over time, additive synthesis describes a collection of algorithms each characterised by the time-varying linear combination of basis components to generate temporal evolution of timbre. Basis components include exactly harmonic partials, inharmonic partials with time-varying frequency or non-sinusoidal waveforms each with distinct spectral characteristics. Additive synthesis of polyphonic musical instrument tones requires a large number of independently controlled partials incurring a large computational overhead whose investigation and reduction is a key motivator for this work. The thesis begins with a review of prevalent synthesis techniques setting additive synthesis in context and introducing the spectrum modelling paradigm which provides baseline spectral data to the additive synthesis process obtained from the analysis of natural sounds. We proceed to investigate recursive and phase accumulating digital sinusoidal oscillator algorithms, defining specific metrics to quantify relative performance. The concepts of phase accumulation, table lookup phase-amplitude mapping and interpolated fractional addressing are introduced and developed and shown to underpin an additive synthesis subclass - wavetable lookup synthesis (WLS). WLS performance is simulated against specific metrics and parameter conditions peculiar to computer music requirements. We conclude by presenting processing architectures which accelerate computational throughput of specific WLS operations and the sinusoidal additive synthesis model. In particular, we introduce and investigate the concept of phase domain processing and present several “pipeline friendly” arithmetic architectures using this technique which implement the additive synthesis of sinusoidal partials

Timing Signals and Radio Frequency Distribution Using Ethernet Networks for High Energy Physics Applications

Timing networks are used around the world in various applications from telecommunications systems to industrial processes, and from radio astronomy to high energy physics. Most timing networks are implemented using proprietary technologies at high operation and maintenance costs. This thesis presents a novel timing network capable of distributed timing with subnanosecond accuracy. The network, developed at CERN and codenamed “White- Rabbit”, uses a non-dedicated Ethernet link to distribute timing and data packets without infringing the sub-nanosecond timing accuracy required for high energy physics applications. The first part of this thesis proposes a new digital circuit capable of measuring time differences between two digital clock signals with sub-picosecond time resolution. The proposed digital circuit measures and compensates for the phase variations between the transmitted and received network clocks required to achieve the sub-nanosecond timing accuracy. Circuit design, implementation and performance verification are reported. The second part of this thesis investigates and proposes a new method to distribute radio frequency (RF) signals over Ethernet networks. The main goal of existing distributed RF schemes, such as Radio-Over-Fibre or Digitised Radio-Over-Fibre, is to increase the bandwidth capacity taking advantage of the higher performance of digital optical links. These schemes tend to employ dedicated and costly technologies, deemed unnecessary for applications with lower bandwidth requirements. This work proposes the distribution of RF signals over the “White-Rabbit” network, to convey phase and frequency information from a reference base node to a large numbers of remote nodes, thus achieving high performance and cost reduction of the timing network. Hence, this thesis reports the design and implementation of a new distributed RF system architecture; analysed and tested using a purpose-built simulation environment, with results used to optimise a new bespoke FPGA implementation. The performance is evaluated through phase-noise spectra, the Allan-Variance, and signalto- noise ratio measurements of the distributed signals

Radar Technology

In this book “Radar Technology”, the chapters are divided into four main topic areas: Topic area 1: “Radar Systems” consists of chapters which treat whole radar systems, environment and target functional chain. Topic area 2: “Radar Applications” shows various applications of radar systems, including meteorological radars, ground penetrating radars and glaciology. Topic area 3: “Radar Functional Chain and Signal Processing” describes several aspects of the radar signal processing. From parameter extraction, target detection over tracking and classification technologies. Topic area 4: “Radar Subsystems and Components” consists of design technology of radar subsystem components like antenna design or waveform design

Abstracts on Radio Direction Finding (1899 - 1995)

The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography). Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM. The contents of these files are: 1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format]; 2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format]; 3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion