• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 35
  • 33
  • 22
  • 8
  • 6
  • 6
  • 6
  • 6
  • 3
  • 2
  • 1
  • Tagged with
  • 144
  • 144
  • 63
  • 39
  • 29
  • 24
  • 21
  • 20
  • 17
  • 17
  • 16
  • 16
  • 16
  • 16
  • 16
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Επικοινωνίες μέσω της γραμμής ρεύματος

Αναστασέλος, Θωμάς 06 February 2008 (has links)
Σκοπός της εργασίας αυτής είναι να εξετασθεί πως μπορεί να πραγματοποιηθεί η μεταφορά δεδομένων μέσω των γραμμών ρεύματος, ποιοι είναι οι ανασταλτικοί παράγοντες σε αυτή τη διαδικασία, με ποιους τρόπους μπορεί να εξασφαλίσουμε όσο το δυνατόν λιγότερα σφάλματα και πως μπορεί να υλοποιηθεί αυτό στην πράξη. Για τα παραπάνω θα γίνουν προσομοιώσεις με βάση πειραματικά δεδομένα που έχουν δημοσιευτεί, αλλά όχι δικά μας πειράματα σε πραγματικές γραμμές. Λόγω της χαμηλής ποιότητας της μεταφοράς αυτής προτείνεται και μια μέθοδος η οποία προσαρμόζεται στις συνθήκες του εκάστοτε καναλιού και ελαχιστοποιεί τα προβλήματα αυτού. Αρχικά αναλύονται και περιγράφονται τα διάφορα μοντέλα που έχουν προταθεί για την περιγραφή ενός συστήματος PLC. Στη συνέχεια, εξετάζεται ο τρόπος μετάδοσης που θα χρησιμοποιηθεί, δηλαδή τα OFDM, καθώς και διάφορες κωδικοποιήσεις και διαμορφώσεις που χρησιμοποιούνται. Κατόπιν, με χρήση των δύο παραπάνω, δηλαδή του μοντέλου του καναλιού και του τρόπου μετάδοσης, προχωράμε σε μια προσομοίωση του όλου συστήματος για να εξετάσουμε τα πιθανά σφάλματα και να κάνουμε τις απαραίτητες βελτιώσεις. Στις προσομοιώσεις αυτές θέλουμε να υπάρχουν λίγα σφάλματα αλλά υψηλή ταχύτητα μετάδοσης. Τα αποτελέσματα των προσομοιώσεων αυτών δεν είναι ικανοποιητικά για εμάς, οπότε προτείνουμε έναν τρόπο βελτίωσης του τελικού αποτελέσματος, ο οποίος βασίζεται στην αναγνώριση του καναλιού από το οποίο γίνεται η μετάδοση ώστε να μηδενιστεί το σφάλμα. Με χρήση αυτής της αναγνώρισης του καναλιού, έχουμε πολύ καλά αποτελέσματα, αφού μόνο σε περιπτώσεις πολύ υψηλού θορύβου έχουμε μεγάλο σφάλμα. Όταν ο θόρυβος πέφτει σε φυσιολογικά επίπεδα τότε το σφάλμα είναι σχεδόν μηδενικό, όποτε μπορεί να θεωρηθεί ότι η μετάδοση γίνεται σωστά. Τελικά προσομοιώνουμε ένα σύστημα το οποίο μεταδίδει στο φάσμα 5-15MHz ενώ τα δεδομένα μας αποστέλλονται με ταχύτητα 64Mbps. / The purpose of this project is to test the power line channel as a communication channel. We test deifferent models of the channel and simulate the data transfer. Finally we get good results as we use a channel estimation to improve the transfer quality. The tranfer is at the band of 5-15MHz, with 64Mbps.
22

Τεχνικές διαποδιαμόρφωσης για πολυκαναλική μετάδοση σε γραμμές χαμηλής τάσης ενός κτηρίου

Χριστοδούλου, Ευριδίκη 31 March 2008 (has links)
Σύγκριση μεθόδων διαμόρφωσης και αποδιαμόρφωσης για πολυκαναλική μετάδοση σε γραμμές χαμηλής τάσης.Εφαρμογή 4,8 και 16 QAM διαμόρφωση και υλοποίηση με αλγόριθμο bit loading.Σύγκριση γραφικών παραστάσεων snr-ber / Comparison of modulation methods for power line communication.Application of 4,8 and 16 qam and bit loading algorithm.Comparison of snr-ber figures
23

Analytical calculation model used when dimensioning timber poles used as overhead power line supports / Analytisk beräkningsmodell för att dimensionera trästolpar som används som luftledningsstolpar

Ekängen, Christopher January 2018 (has links)
Overhead power lines are more reliable and cost effective than underground cables when it comes to power transmission. The overhead power lines are often suspended above ground using timber pole supports. As the placement of each support depends upon topography amongst other things the conditions for most of the supports will be different and each pole can be viewed as a unique object. This requires that each support is dimensioned individually. The purpose of the project is to clarify how the dimensioning of a support should be performed. The main objective for the project is to develop an analytical model and simulation tool which can be used to dimension timber pole supports. Octave, a scientific programming language, is used for the simulation tool and to visualize the analytical model for the timber pole supports. The analytical model is validated by a finite element analysis, which is applied using the program ABAQUS/CAE. From the analytical model nomograms, which are diagrams that relate the parameters of the support, can be constructed. A nomogram is another tool that can be used when dimensioning timber supports. Many relevant design aspects are treated in the standard SS-EN 50341 and serves as the basis for the analytical calculation model. The supports can be divided into three main types; tangential supports, where the conductors continue straight at the support, angle supports, where the conductors make an angle at the support, and terminal supports, which are used at the endpoint of the conductors. Loads taken into account are: self-weight of components, wind, ice, conductor tension and maintenance. The loads are combined using a design equation which takes into account the probability of certain events occurring simultaneously using combination factors. Partial safety factors are also used to take into account possible deviations in loads, material or geometry. The failure modes of interest are rupture due to excessive bending loads and buckling due to excessive axial loads in the support legs. In the analytical calculations the timber is considered to be isotropic in accordance with the standard while the timber is modeled both as isotropic and orthotropic in the finite element analysis. The analytical model assumes that the cross-arm, which is the horizontal part of the support, only acts to distribute the load between the legs of the support without providing any extra stability by linking them together. In the finite element analysis the legs of the support are considered both individually and linked together by a cross-arm to test the validity of the assumption. To compare the results from the analytical model with finite element analysis one support of each type; tangential, angular and terminal is selected. An Octave script is written and applied to the selected supports to calculate their necessary dimensions. Based on the calculated dimensions 3D-models are created using PTC Creo Parametric 3.0 which then are imported into ABAQUS/CAE where the supports are subjected to finite element analysis. In addition to using the analytical model directly expressions that can be used to create nomograms for timber supports are also derived. Comparing results from FEM with the analytical model showed that the tangential and angular supports were over-dimensioned while the terminal supports were under-dimensioned in the analytical model. This means that a smaller dimension could be used for the tangential and angular supports. For the terminal support the analytical model needs to be altered so that failure will not occur. Changing the buckling mode for the terminal support in the analytical solution fixed the under-dimensioning issue. The finite element calculations where a cross-arm was used to link the legs of the support together showed no increased stability for buckling but showed lower bending stresses in the support legs. Using an orthotropic material model for the timber did not effect the calculations greatly as the properties in the length direction of the pole were significantly more important than the properties in the perpendicular directions. Dimensioning using nomograms is less accurate, as it only narrows the results down to a timber pole grade rather than a specific diameter. This decrease in accuracy is not cause for concern as the timber poles are ordered by grade and not a specific diameter. Using nomograms can give quick results when it comes to dimensioning. / Luftledningar är mer tillförlitliga och kostnadseffektiva än markkablar när det kommer till kraftöverföring. För att hålla luftledningar ovan mark används ofta trästolpar. Placeringen av varje stolpe beror bland annat på topografin vilket gör att villkoren för nästan varje stolpe skiljer sig åt. Detta gör att varje stolpe måste dimensioneras individuellt. Projektets syfte är att klargöra på vilket sätt dimensionen för en stolpe ska bestämmas. Det huvudsakliga målet är att utveckla en analytisk modell som kan användas för att dimensionera trästolpar. Octave, ett vetenskapligt programspråk, används för att tillämpa den analytiska modellen på trästolparna. Den analytiska modellen valideras med finit elementanalys, som tillämpas genom användandet av ABAQUS/CAE. Från den analytiska modellen kan också nomogram konstrueras vilket är ett annat sätt att dimensionera stolpar genom att används diagram som relaterar stolparnas parametrar. Många av de relevanta designaspekterna som berör stolpar behandlas i standarden SS-EN 50341 och ligger till grund för den analytiska modellen. Stolparna kan delas in i tre huvudtyper; raklinjestolpar, där ledarna fortsätter rakt vid stolpen, vinkelstolpar, där ledarna avviker med en vinkel, och ändstolpar, som används vid avslut av ledarna. De laster som beaktas är egenvikt hos komponenter, vind, is, spänning i ledare och underhåll. För att kombinera lasterna används en designekvation som tar hänsyn till sannolikheten att vissa händelser sker samtidigt genom att applicera kombinationsfaktorer. Dessutom används partialsäkerhetsfaktorer för att kompensera för eventuella avvikelser i last, material eller geometri. Stolparna dimensioneras mot brott på grund av för hög böjande belastning och knäckning på grund av för hög axialbelastning. I de analytiska beräkningarna antas trä vara ett isotropt material i enlighet med standarden medan det modelleras både som isotropt och ortotropt vid analys med finita elementmetoden. Vidare antas att regeln, den horisontella delen av stolpen, endast fördelar lasten mellan stolpens ben utan att bidra med någon extra stabilitet genom att länka benen samman. För att testa detta antagande modelleras stolpbenen både individuellt och sammanlänkade med en regel vid analys med finita elementmetoden. För att kunna jämföra resultatet från den analytiska modellen med finit elementanalys väljs en stolpe av varje typ; raklinje-, vinkel-, och ändstolpe, ut. Ett skript skrivs i Octave och tillämpas på de utvalda stolparna för att bestämma vilka dimensioner som krävs. Baserat på de beräknade dimensionerna skapas 3D-modeller i PTC Creo Parametric 3.0 vilka sedan importeras till ABAQUS/CAE för analys med finita elementmetoden. Förutom att tillämpa den analytiska modellen direkt härleds uttryck för att kunna generera nomogram. En jämförelse av resultaten från FEM med den analytiska modellen visade att raklinje- och vinkelstolpar blev överdimensionerade medan ändstolpar blev underdimensionerade. Detta innebär att en mindre dimension kan användas för raklinje- och vinkelstolpar. För ändstolpar måste modellen korrigeras för att stolpen ska hålla. Genom att ändra knäckningsfall för ändstolpen i den analytiska modellen löstes problemet med underdimensionering. Beräkningarna i finita elementmetoden där en regel användes för att sammanlänka stolpbenen visade ingen ökad stabilitet för knäckning men böjspänningarna i stolpbenen blev lägre. Att använda en ortotrop materialmodell påverkade inte beräkningarna nämnvärt eftersom egenskaperna i längsriktningen var mycket mer signifikanta än egenskaperna i tvärriktningarna. Vid dimensionering med hjälp av nomogram fås en sämre noggrannhet, eftersom resultatet endast blir en viss stolpklass istället för en specifik diameter. Denna minskade noggrannhet är ingen anledning till oro eftersom trästolparna beställs utifrån klass och inte utifrån specifik diameter. Användandet av nomogram kan ge snabba resultat vid dimensionering.
24

Comunicação cooperativa e em diversidade para power line communication

Fernandes, Daniel Leocádio 27 September 2012 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-24T11:27:36Z No. of bitstreams: 1 danielleocadiofernandes.pdf: 2042919 bytes, checksum: c8ee87c6b0e8118f3fdb4cd6ebbc26c6 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-04-24T16:54:33Z (GMT) No. of bitstreams: 1 danielleocadiofernandes.pdf: 2042919 bytes, checksum: c8ee87c6b0e8118f3fdb4cd6ebbc26c6 (MD5) / Made available in DSpace on 2017-04-24T16:54:33Z (GMT). No. of bitstreams: 1 danielleocadiofernandes.pdf: 2042919 bytes, checksum: c8ee87c6b0e8118f3fdb4cd6ebbc26c6 (MD5) Previous issue date: 2012-09-27 / A presente contribuição apresenta investigações e análises da comunicação cooperativa e em diversidade para melhorar a cobertura e o desempenho de sistemas power line communication (PLC) em redes de distribuição de energia elétrica externas e de baixa tensão. Neste contexto, o desempenho dos protocolos de cooperação amplificar e retransmitir (amplify and forward - AF); amplificar, equalizar e retransmitir (amplify, equalize, and forward - AEF) e decodificar e retransmitir (decode and forward - DF) é analisado quando existe um nó de retransmissão ou de cooperação entre os nós de origem e destino. Os esquemas orthogonal frequency division multiplexing (OFDM) e single carrier with cyclic prefix (SC-CP); a modulação coerente 4-QAM, o canal PLC modelado como linear e invariante no tempo, ruído aditivo modelado additive white Gaussian noise (AWGN) e additive impulsive Gaussian noise (AIGN) constituem os esquemas de modulação adotados e o meio de comunicação de dados. Os resultados indicam que a cooperação traz benefícios para sistemas PLC e, portanto, é de grande interesse a sua introdução nas novas gerações de transceptores PLC. Além disso, considerando o esquema OFDM, modulação 4-QAM e cenário de simulação baseado nas mesmas premissas adotadas para avaliar a comunicação cooperativa, a comunicação em diversidade, baseada na seleção das sub-portadoras, foi analisada visando, sobretudo, verificar os ganhos que podem ser obtidos em relação a robustez e confiabilidade de transceptores PLC, os quais são voltados para o atendimento dos requisitos de qualidade de serviços de aplicações smart grid communication, tal como smart metering. Os resultados numéricos, obtidos através de simulações computacionais, confirmam que o aumento da diversidade melhora a confiabilidade dos sistemas PLC, mas reduz a vazão do mesmo. Assim sendo, comunicação em diversidade é promissora para smart metering, posto que, para esta aplicação, confiabilidade e robustez são requisitos de maior importância do que elevada vazão. / This thesis aims at investigating and analyzing cooperative communication as well as communication with diversity to improve the coverage and the performance of power line communication (PLC) systems in outdoor and low-voltage distribution electric grids. In this context, the performance of cooperative protocols, such as amplify and forward (AF); amplify, equalize, and forward (AEF); and decode and forward (DF), are analyzed when only one relay, between the source node and destination node, is considered. The orthogonal frequency division multiplexing (OFDM) and single carrier with cyclic prefix (SC-CP) schemes; 4-QAM coherent modulation; linear and time invariant PLC channels, additive noise modeled as additive white Gaussian noise (AWGN) and additive impulsive Gaussian noise (AIGN) constitute the end-to-end communication link for performance evaluation. The performance results show that cooperation can offer benefits to PLC systems and, as a consequence, its introduction in new generations of PLC transceivers could be beneficial. Additionally, by taking into account the OFDM scheme, 4-QAM coherent modulation and the same constraints applied to analyze the cooperative communication, the communication with diversity, in which a subcarrier selection criterion is adopted, was also investigated and analyzed. The purpose of addressing diversity is to highlight what kind of gains can be obtained to improve the reliability and robustness of PLC transceivers, in order to fulfill the requirements of smart grid communication, such as smart metering. The numerical results verify that diversity can indeed increase the reliability and robustness of PLC transceivers, however it reduces the throughput. For smart metering, communication with diversity seems to be promising because reliability and robustness are much more important requirement than higher throughput.
25

Monitor napájecí sítě / Power Line Monitor

Strašek, Petr January 2018 (has links)
This thesis solves the development of Power Line Monitor. The thesis also describes the specific implementation of hardware, software and results.
26

Réseau de communication courant porteur en ligne pour la collecte d'informations et le diagbostic d'équipements embarqués dans l'aéronef / Power line communication applied for the collection of informations and equipment diagnosis on an aircraft.

Brison, Mickael 03 July 2018 (has links)
Ces travaux portent sur la faisabilité de l'établissement d'un réseau Courant Porteur de Ligne (CPL) pour transmettre des données de maintenance prédictive dans le domaine aéronautique. Le CPL est identifié comme solution afin d'augmenter le nombre d'informations échangées sans modifications du câblage déjà présent dans l'avion. L'approche adoptée au cours de cette thèse porte sur l'adaptation des solutions CPL existantes sur le marché afin qu'elles puissent être déployées sur un réseau avionique classique. Ces modifications doivent respecter les normes aéronautiques qui intègrent notamment sur la protection foudre (DO-160) et les mécanismes de couplage pour assurer la liaison de communication sur les lignes de puissance. Des expérimentations ont été réalisées pour vérifier les performances que les solutions CPLs pourraient attendre en utilisant le ratio signal sur bruit (SNR) comme paramètre de comparaison.Un montage permettant de respecter à la fois la contrainte de protection à la foudre et le fonctionnement des transmissions CPM a été identifié et évalué par le biais de simulations et d’expérimentations en laboratoire. Ce montage nous a permis d'augmenter le SNR de la liaison CPL jusqu'à 40dB. Les circuits de couplage présents sur les modems CPL du commerce ont été optimisés afin de mieux s'adapter à l'environnement aéronautique. La conception de ces circuits sont complètement décrites, dont notamment la réalisation du transformateur HF permettant l'adaptation d'impédance. Une fois les modifications effectuées, nous avons réalisé une série de mesures d’émissions conduites générées les chipsets afin de vérifier leur conformité aux normes CEM DO-160. Les tests ont porté sur des modems classiques et des modems modifiés liés à un équipement classique avionique. Ces tests nous ont montré que, sans les modifications proposées au niveau du circuit de couplage, il est impossible de communiquer sur des lignes fortement bruitées. Dans le cas de bruits générés à la limite de la norme DO-160, notre modem modifié atteint un débit de 46 Mbps en émission et 36 Mbps en réception. Dans cette dernière manipulation, nous atteignons dans un pire cas de perturbations un débit supérieur à celui de notre cahier des charges. / This work focuses on the feasibility of a Power Line Communication (PLC) network for transmitting predictive maintenance data on avionics power lines. PLC is identified as a solution to increase the number of information exchanged without modification of the wiring already present in the aircraft. The approach taken in this thesis deals with the adaptation of existing PLC solutions on the market so that they can be deployed on a conventional avionics network. These modifications include lightning protection and coupling circuits to ensure the communication over the power network. Experiments were conducted to verify the performance that PLC solutions could expect by using the signal-to-noise ratio (SNR) as a comparison paramater.A circuit allowing to respect lightning protection constraints and that allow PLC transmissions has been identified and evaluated by means of simulations and laboratoy experiments. This modificatiosn allowed us to cincrease the SNR of the PLC link up to 40dB. Coulpling circuits on commercial CPL modems have been optimized to better adapt PLC signal to the avionic environment. The design of these circuits is completely described, including the realization of the HF transformer for impedance matching. Once the changes were made, we performed a series of conducted emissions measurements that generated the chipstets to verify their compliance with the CEM DO-160 standarts. The tests focused on conventional modems and modified modems related to conventional avionics equipment. These tests showed us that, without the proposed modifications at the level of the coupling circuit, it is impossible to communicate on very noisy lines. In the case of noise generated at the limit of the DO-160 standart, our modified modem achieves a data rates of 46 Mbps for transmission and 36 Mbps for reception. In this last manipulation, we reach in a worse case of disturbances a data rate higher than the specifications needed.
27

Power Line Communications over Power Distribution Networks of Microprocessors - Feasibility Study, Channel Modeling, and a Circuit Design Approach

Thirugnanam, Rajesh 24 January 2008 (has links)
Power line communications (PLC) has been considered by utility companies for over a half century and for home networking in recent years. However, PLC at the IC level, or even at the PCB level, has not been investigated outside Dr. Ha's research group. This thesis investigates the feasibility of PLC over power distribution networks (PDNs) of advanced microprocessors. A PDN in an integrated circuit (IC) is ubiquitous as seen by the internal logic, i.e., a power line is accessible to any internal node. This suggests the possibility of monitoring or controlling the logic value of any internal node through a power line by attaching a simple sensing/control circuit to the node. Routing the data through a power line avoids the necessity of preplanning the routing of a data path between the node and an external data pin. PLC over microprocessor PDNs also provide a viable means for "run-time testing" as well as for monitoring the so called "large time-constant errors" resulting from aging and temperature variations. In this thesis, we considered impulse-based ultra wideband (I-UWB) communication technology for PLC over PDNs of microprocessors. I-UWB has several advantages for PLC over PDNs due to its robustness to multipath effects, simple hardware for transmission and reception of pulses and, more importantly, reduced interference to the normal operation of microprocessors. A microprocessor PDN is heavily decoupled to damp the resonances in the power supply impedance as well as to reduce the slew rate of current variations by locally supplying (sinking) currents to (from) the switching nodes. Consequently, a PDN behaves like a bulky lowpass filter for high frequency signals. However, the inductance component of decoupling capacitors becomes more significant beyond the self resonant frequency (SRF) of the capacitors. So, a PDN becomes essentially a distributed circuit beyond the SRF and is no longer a lowpass filter. Indeed, high frequency PDN models developed earlier at Dr. Ha's group show that there exist multiple frequency bands where high frequency signals can propagate through the PDN with relatively low attenuation [3] [4]. The major contributions of our research lie in three areas. First, we verified existence of passbands on PDN's transfer characteristics through measurements. We carried out high frequency measurements on the PDN of Intel's 65 nm Pentium processor and 45 nm Core 2 Duo processor. We measured PDN transfer characteristics up to several GHz from a core power pin on a tester board to an on-chip power node for both active and cold microprocessor dies. The measurements show the existence of narrow, sporadic and migratory passbands i.e. location of passbands change from one generation of processor to the next. The migratory nature of passbands requires the I-UWB receiver and a transmitter to cover a wide range of frequencies rather than a specific passband. Second, we have developed a PDN communication channel model for system level study. To develop the channel model, we also performed noise measurements on Intel microprocessors. The link budget was calculated based on the channel model and appropriate modulation schemes were suggested through the system level study. Third, we investigated design of an I-UWB receiver and a transmitter, which cover a wide bandwidth. The proposed receiver and transmitter designs were evaluated through simulations in TSMC 0.18 μm CMOS process. Our simulation indicates that the PLC over a PDN is feasible with a relatively simple digital-process friendly I-UWB receiver and a transmitter. / Ph. D.
28

The Dual Use of Power Distribution Networks for Data Communications in High Speed Integrated Circuits

Chung, Woo Cheol 17 February 2006 (has links)
This thesis investigates a new data communication method in high speed integrated circuits using power distribution networks (PDNs). The conventional purpose of PDNs in integrated circuits (ICs) is to deliver power to internal nodes of an IC while meeting a level of power integrity. As the power consumption increases for very large scale integration (VLSI) systems, the number of power/ground pins increases as well. In this thesis, we propose to use PDNs for dual purposes, delivery of power and one-/two-way data communications, which is highly beneficial for pin-limited high performance ICs. To this end, we investigate signaling methods for a microscopic communication channel. Impulse-based ultra wideband (UWB) signaling is selected due to its robustness to noise and wideband characteristics. Next, we study a planar structure IC package based on the cavity resonator model (CRM) as a communication channel. Impedance characteristics of a planar structure IC package and other relevant components of an IC are important, and they are investigated for data transmission over power distribution networks. Another important aspect of the study is data transmission and reception, which we investigate through simulations. Finally, we study one possible application for one way communications, massive parallel scan design, which greatly shortens the testing time at moderate overhead. The performance is measured with eye diagrams and bit error rates (BERs) under the presence of voltage drop, simultaneous switching noise, and thermal noise. / Ph. D.
29

A Reliable CMOS Receiver for Power Line Communications in Integrated Circuits

Salem, Jebreel Mohamed Muftah 24 January 2013 (has links)
Power line communications (PLC) in integrated circuits (ICs) was proposed by Dr. Dong S. Ha's group in 2005. Their goal was to utilize the power distribution network for data communications as well as delivery of power, so that the routing overhead can be avoided and the number of pins in the chip can be reduced. Dr. Ha's group demonstrated through measurements the existence of pass-bands in the power distribution networks and the feasibility of power line communications in ICs. Several PLC receivers were developed to recover data superimposed on the power lines of an IC. This thesis research investigated a new PLC receiver to improve shortcomings of previous PLC receivers, specifically to improve the reliability while reducing power dissipation. The proposed PLC system adopts an amplitude shift keying (ASK) modulation to transmit and detect data through power distribution networks. The proposed PLC receiver consists of three main sub-blocks. The first sub-block is a level shifter, which lowers the offset voltage of the supply voltage to approximately 0.5VDD. The second sub-block is a signal extractor, which detects a data signal superimposed on the power line. The signal extractor is a differential amplifier, in which one input is connected through an RC low-pass filter. The DC voltage of the data signal varies in accordance with the supply voltage fluctuations and droop. The low-pass filter intends to pass only the DC term of the data signal. Since the DC voltage is common for both inputs of the differential amplifier, it is removed from the data signal through the common mode rejection of the differential amplifier. Therefore, the signal extractor can mitigate supply voltage fluctuations and droops. The last sub-block is the logic restorer, which converts the differential signal to a logic value based on a Schmitt trigger. The hysteresis of the Schmitt trigger improves the noise immunity of the receiver The proposed PLC receiver is designed and fabricated in CMOS 0.18 µm technology under the supply voltage of 1.8 V. Measurement results of the three sub-blocks and the entire PLC receiver are presented and compared with simulation results. The data rate for the measurements is set to 10.0 Mbps, and the ASK modulation scheme adopts VDD (= 1.8 V) for logic 0 and 90 mV above VDD for logic 1. The measurements show that the PLC receiver can tolerate the supply voltage drop by 0.423 V or 23.0%. The power dissipation for the receiver is 3.2 mW under 1.8 V supply. The core area of the receiver is 72.2 µm x 74.9 µm. / Master of Science
30

Power Line Communications in Microprocessors - System Level Study and Circuit Design

Chawla, Vipul 14 October 2009 (has links)
Power line communications (PLC) as applied to electrical power grid is known since long; however, PLC in microprocessors was recently introduced by VTVT Lab. Since power distribution network (PDN) inside a microprocessor is ubiquitous, therefore, any node inside a microprocessor can be accessed by attaching a simple communication circuit to it. The scheme is extremely attractive as it avoids the routing overhead of the data-path between an internal node and an I/O pin. A number of applications are possible for PLC in microprocessors such as on-line testing, monitoring/control of internal nodes, fault diagnosis etc. Feasibility of the PLC approach has been extensively studied by earlier researchers at VTVT. The feasibility studies investigated the frequency response of a microprocessor's PDN and looked for existence of passbands — frequency bands where signal attenuation through the PDN is small. Two different approaches were followed—the first approach employed analytical modeling of the high frequency characteristics of the PDN, while the second approach conducted measurements on Intel® microprocessors' PDN. Although, differences were observed in the results of the two approaches; both the approaches demonstrated existence of passbands, thus affirming the feasibility of the PLC scheme. This thesis presents a system level study conducted to estimate performance of the PLC scheme. Measurement results were used to model the PDN channel. The study provides useful insights for the design of microprocessor level PLC system. Specifically, the study estimates optimal pulse width required to maximize the system performance and the range of achievable data-rates. The study demonstrates that it is feasible to communicate data through a microprocessor's PDN without inducing large disturbances on the power line. The other work presented in this thesis is the design of low power receiver for microprocessor level PLC, also called data recovery block. The proposed design of data recovery block employs Correlation Detection (CD) receiver architecture. The design has been implemented in IBM 0.13 µm CMOS process and has been verified to operate reliably across Process, Voltage and Temperature variations. The design has a small foot-print of 300 µm x 160 µm and consumes 3.58 mW while operating from 1.2 V power supply. / Master of Science

Page generated in 0.0374 seconds