Aplicaciones avanzadas del principio superregenerativo a comunicaciones por radiofrecuencia

There exists today an increasing demand for wireless devices which require low cost and minimum power consumption radiofrequency front-ends. Precisely, these are two remarkable characteristics of the superregenerative receiver (SR). In this thesis, we present some novel applications of the SR receiver which make use of both simple methods and simple implementations that fit perfectly with its main features. The superregenerative reception principle was presented for the first time in 1922, and it was initially used with analog amplitude modulations, such as voice communications. The same principle was spread to digital amplitude modulations in applications where data transmission was required. Moreover, it has also been used in frequency modulation reception through an FM-to-AM conversion mechanism, but due to the inherent characteristics of the receiver, it is only suitable with wide band modulations.In the latest few years, some SR receiver proposals for phase modulation detection have emerged. It has been demonstrated that, with this type of modulation, the resulting architecture might be even simpler than the traditional ones devoted to detect amplitude modulations. This thesis advances in this line and its main goal is to discover new possibilities of the SR receiver in angular modulation detection, which have been little exploited so far. With this aim, a variety of prototypes were designed and implemented for PSK modulations on the one hand and, on the other hand, for narrow band FSK modulations. More specificifically, the thesis describes a SR QPSK transceiver and a SR M-PSK transceiver. These transceivers make use of a digital phase detection technique that is very simple. In order to confirm the viability of the proposed idea, some implementations in the HF band operating at a symbol rate of 10 kHz were developed. Regarding frequency modulations, we present a SR receiver detection method suitable for the narrowband case. This method is based on the observation of the instantaneous phase once per symbol, so that we are able to detect the received frequency through the value of the detected phase. For this case two implementations are presented: a SR receiver for Sunde's FSK modulation, and a SR receiver for MSK modulation. By using the designed SR receiver for the MSK modulations as a starting point, a SR MSK transceiver compatible with the IEEE 802.15.4 standard is implemented. This standard defines the physical layer and the medium access control (MAC) layer used for low speed wireless personal area network, a field in which the SR receiver fits perfectly. Finally, we describe a synchronization method for SR MSK receivers at the symbol, chip and frame levels. This method is presented in a general way and it is able to sinchronize through any preamble satisfying some specific requirements. In particular, we describe an implementation that aims to synchronize IEEE 802.15.4 standard frames. Simplicity has been prioritized in all the presented designs and implementations in order to potentiate the characteristic low cost and low power consumption features of the SR receiver. Likewise, we prove that this kind of receiver is especially efficient in the detection of phase and narrowband frequency modulations.Actualmente existe una demanda creciente de dispositivos inalámbricos que requieren el uso de front-ends de radiofrecuencia de bajo coste y consumo de potencia reducido, requisitos en los que el receptor superregenerativo (SR) destaca de forma especial. En esta tesis, se presentan distintas aplicaciones novedosas del receptor SR con métodos e implementaciones simples en consonancia con sus principales prestaciones. El principio de recepción superregenerativo fue presentado en el año 1922, siendo utilizado en sus inicios para modulaciones analógicas de amplitud como, por ejemplo, comunicaciones de voz. El mismo principio fue extendido posteriormente a modulaciones de amplitud digitales en aplicaciones que requerían la transmisión de datos. Por otro lado, también se ha utilizado en la recepción de modulaciones de frecuencia, mediante un mecanismo de conversión de modulación de frecuencia a modulación de amplitud. Sin embargo, debido a las características intrínsecas del receptor, este solo resulta adecuado para modulaciones de banda ancha. En los últimos años, han surgido algunas propuestas de receptor SR para modulaciones de fase. Se ha demostrado que, con este tipo de modulaciones, la arquitectura resultante puede ser incluso más simple que las tradicionales para la detección de modulaciones de amplitud. Esta tesis avanza precisamente en esta línea y tiene como objetivo descubrir nuevas posibilidades de utilización del receptor SR en la detección de modulaciones angulares, poco explotadas hasta el momento en combinación con este tipo de receptor. Con este objetivo, se diseñan e implementan diversos prototipos para modulaciones de fase PSK, por un lado, y para modulaciones de frecuencia FSK de banda estrecha, por otro. Más concretamente, se describe un transceptor SR QPSK y un transceptor SR M-PSK. Estos transceptores se basan en una técnica de detección de fase digital de gran simplicidad. Se han realizado implementaciones en la banda de HF operando a una frecuencia de símbolo de 10 kHz, con el fin de demostrar la viabilidad del concepto propuesto. Con respecto a las modulaciones de frecuencia, se presenta un método de detección con receptor SR para el caso de banda estrecha. Este método se basa en observar la fase instantánea una vez por símbolo, consiguiendo detectar la frecuencia recibida a través del valor de la fase detectada. En este caso, se presentan dos implementaciones: un receptor SR para la modulación FSK de Sunde y un receptor SR para la modulación MSK. Utilizando el receptor SR para la modulación MSK diseñado como punto de partida, se implementa un transceptor SR MSK compatible con el estándar 802.15.4. Este estándar define la capa física y la capa de control de acceso al medio (MAC) para redes inalámbricas de área personal de baja velocidad, ámbito en el cual el receptor SR encaja a la perfección. Finalmente, se describe un método de sincronización para receptores SR MSK a nivel de símbolo, de chip y de trama. Este método se presenta de forma genérica, pudiéndose sincronizar con cualquier preámbulo que cumpla unas características determinadas. En particular, se describe una implementación que tiene como objetivo sincronizar tramas del estándar IEEE 802.15.4

A proof-of-concept superregenerative QPSK transceiver

In this paper we present a description and experimental verification of an HF-band proof-of-concept superregenerative transceiver for QPSK signals. We describe a simple implementation of an all-digital, FPGA-based, QPSK transmitter section. On the receiver side, the quench signal is generated in the same FPGA with a minimum of analog circuitry. As the main novelty, we present a simple synchronization scheme suitable for packetized transmissions.Peer ReviewedPostprint (author’s final draft

Joint symbol and chip synchronization for a burst-mode-communication superregenerative MSK receiver

In this paper we describe a superregenerative (SR) MSK receiver able to operate in a burst-mode framework where synchronization is required for each packet. The receiver is based on an SR oscillator which provides samples of the incoming instantaneous phase trajectories. We develop a simple yet effective technique to achieve joint chip and symbol synchronization within the time limits of a suitable preamble. We develop some general results and focus on the case of the IEEE 802.15.4 MSK physical layer. We provide details on a VHDL implementation on an FPGA where the most complex digital processing block is an accumulator. Simulation and experimental results are provided to validate the described technique.Peer ReviewedPostprint (published version

Global, regional, and national life expectancy, all-cause mortality, and cause-specific mortality for 249 causes of death, 1980-2015 : a systematic analysis for the Global Burden of Disease Study 2015

Background Improving survival and extending the longevity of life for all populations requires timely, robust evidence on local mortality levels and trends. The Global Burden of Disease 2015 Study (GBD 2015) provides a comprehensive assessment of all-cause and cause-specific mortality for 249 causes in 195 countries and territories from 1980 to 2015. These results informed an in-depth investigation of observed and expected mortality patterns based on sociodemographic measures. Methods We estimated all-cause mortality by age, sex, geography, and year using an improved analytical approach originally developed for GBD 2013 and GBD 2010. Improvements included refinements to the estimation of child and adult mortality and corresponding uncertainty, parameter selection for under-5 mortality synthesis by spatiotemporal Gaussian process regression, and sibling history data processing. We also expanded the database of vital registration, survey, and census data to 14 294 geography-year datapoints. For GBD 2015, eight causes, including Ebola virus disease, were added to the previous GBD cause list for mortality. We used six modelling approaches to assess cause-specific mortality, with the Cause of Death Ensemble Model (CODEm) generating estimates for most causes. We used a series of novel analyses to systematically quantify the drivers of trends in mortality across geographies. First, we assessed observed and expected levels and trends of cause-specific mortality as they relate to the Socio-demographic Index (SDI), a summary indicator derived from measures of income per capita, educational attainment, and fertility. Second, we examined factors affecting total mortality patterns through a series of counterfactual scenarios, testing the magnitude by which population growth, population age structures, and epidemiological changes contributed to shifts in mortality. Finally, we attributed changes in life expectancy to changes in cause of death. We documented each step of the GBD 2015 estimation processes, as well as data sources, in accordance with Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER). Findings Globally, life expectancy from birth increased from 61.7 years (95% uncertainty interval 61.4-61.9) in 1980 to 71.8 years (71.5-72.2) in 2015. Several countries in sub-Saharan Africa had very large gains in life expectancy from 2005 to 2015, rebounding from an era of exceedingly high loss of life due to HIV/AIDS. At the same time, many geographies saw life expectancy stagnate or decline, particularly for men and in countries with rising mortality from war or interpersonal violence. From 2005 to 2015, male life expectancy in Syria dropped by 11.3 years (3.7-17.4), to 62.6 years (56.5-70.2). Total deaths increased by 4.1% (2.6-5.6) from 2005 to 2015, rising to 55.8 million (54.9 million to 56.6 million) in 2015, but age-standardised death rates fell by 17.0% (15.8-18.1) during this time, underscoring changes in population growth and shifts in global age structures. The result was similar for non-communicable diseases (NCDs), with total deaths from these causes increasing by 14.1% (12.6-16.0) to 39.8 million (39.2 million to 40.5 million) in 2015, whereas age-standardised rates decreased by 13.1% (11.9-14.3). Globally, this mortality pattern emerged for several NCDs, including several types of cancer, ischaemic heart disease, cirrhosis, and Alzheimer's disease and other dementias. By contrast, both total deaths and age-standardised death rates due to communicable, maternal, neonatal, and nutritional conditions significantly declined from 2005 to 2015, gains largely attributable to decreases in mortality rates due to HIV/AIDS (42.1%, 39.1-44.6), malaria (43.1%, 34.7-51.8), neonatal preterm birth complications (29.8%, 24.8-34.9), and maternal disorders (29.1%, 19.3-37.1). Progress was slower for several causes, such as lower respiratory infections and nutritional deficiencies, whereas deaths increased for others, including dengue and drug use disorders. Age-standardised death rates due to injuries significantly declined from 2005 to 2015, yet interpersonal violence and war claimed increasingly more lives in some regions, particularly in the Middle East. In 2015, rotaviral enteritis (rotavirus) was the leading cause of under-5 deaths due to diarrhoea (146 000 deaths, 118 000-183 000) and pneumococcal pneumonia was the leading cause of under-5 deaths due to lower respiratory infections (393 000 deaths, 228 000-532 000), although pathogen-specific mortality varied by region. Globally, the effects of population growth, ageing, and changes in age-standardised death rates substantially differed by cause. Our analyses on the expected associations between cause-specific mortality and SDI show the regular shifts in cause of death composition and population age structure with rising SDI. Country patterns of premature mortality (measured as years of life lost [YLLs]) and how they differ from the level expected on the basis of SDI alone revealed distinct but highly heterogeneous patterns by region and country or territory. Ischaemic heart disease, stroke, and diabetes were among the leading causes of YLLs in most regions, but in many cases, intraregional results sharply diverged for ratios of observed and expected YLLs based on SDI. Communicable, maternal, neonatal, and nutritional diseases caused the most YLLs throughout sub-Saharan Africa, with observed YLLs far exceeding expected YLLs for countries in which malaria or HIV/AIDS remained the leading causes of early death. Interpretation At the global scale, age-specific mortality has steadily improved over the past 35 years; this pattern of general progress continued in the past decade. Progress has been faster in most countries than expected on the basis of development measured by the SDI. Against this background of progress, some countries have seen falls in life expectancy, and age-standardised death rates for some causes are increasing. Despite progress in reducing age-standardised death rates, population growth and ageing mean that the number of deaths from most non-communicable causes are increasing in most countries, putting increased demands on health systems. Copyright (C) The Author(s). Published by Elsevier Ltd.Peer reviewe

Diseño e implementación de un transceptor super-regenerativo QPSK

[ANGLÈS] This project consists on the design and the implementation of a radio frequency transceiver. A transceiver is a device which is able to be a transmitter and a receiver and, therefore, it is suitable for commuting the working manner in order to communicate to other transceivers. The information is transmitted by a QPSK phase modulation over a radio frequency carrier and a part from this, the information is differentially codified. That means that the data is not directly the received phase at the moment, but it is the difference between two consecutive phases. The received part is made up by an analogical circuit based on a super- regenerative receiver and a FPGA. This type of receiver has a low complexity, low consume, and low cost. The super-regenerative circuit is built of an oscillator able to obtain the information of the entrance sign of the phase. From this signal, the FPGA makes a simple digital post-process in order to obtain the received phases. In this project it has also been solved the synchronism problem between a transceiver on transmitter mode, and another one on receiver mode. It has been created a preamble by which the receiver is able to decide the optimum zone to sample the following data where the information will be in. The transmitting part is in charge of generate the data that we want to transmit, encoding them differentially and modeling them in QPSK over the RF carrier signal. All this process is realized entirely in FPGA, and therefore the transmitter is digital totally. The implementation of a transceiver using a super-regenerative receiver is a quite innovative fact. In this case, the work is mainly produced by a radio frequency sign of 26,25MHz, although it is a prove to verify the correct functioning and it would be perfectly extrapolated to higher frequencies.[CASTELLÀ] Este proyecto consiste en el diseño e implementación de un transceptor de radiofrecuencia. Un transceptor es un dispositivo capaz de ser transmisor y receptor y por lo tanto, ha de poder conmutar el modo de funcionamiento para comunicarse con uno u otros transceptores. La información se transmite utilizando una modulación de fase QPSK sobre una portadora de radiofrecuencia. A parte de esta modulación de fase, la información está codificada diferencialmente. Esto quiere decir que, el dato no es directamente la fase recibida en el momento, sino que éste es la diferencia entre dos fases consecutivas. La parte receptora está formada por un circuito analógico basado en un receptor super-regenerativo y una FPGA. Este tipo de receptor es de baja complejidad, bajo consumo y bajo coste. El circuito super-regenerativo se basa en un oscilador capaz de obtener la información de la fase de la señal entrante. A partir de esta señal la FPGA hace un post-procesado digital simple para obtener las fases recibidas. En este proyecto también se ha resuelto el problema de sincronismo entre un transceptor en modo transmisor y otro en modo receptor. Se ha creado un preámbulo con el cual el receptor es capaz de decidir la zona óptima para poder muestrear los siguientes datos donde habrá la información. La parte transmisora se encarga de generar los datos que se quieren transmitir, codificándolas diferencialmente y modularlas en QPSK sobre la señal RF portadora. Todo este proceso se hace íntegramente en la FPGA, por lo tanto el transmisor es totalmente digital. La implementación de un transceptor utilizando un receptor super-regenerativo es un hecho bastante innovador. En este caso se trabaja con una señal de radiofrecuencia de 26,25 MHz, pero es una prueba para verificar su correcto funcionamiento y sería perfectamente extrapolable a frecuencias más altas.[CATALÀ] Aquest projecte consisteix en el disseny i implementació d'un transceptor de radiofreqüència. Un transceptor és un dispositiu capaç de ser transmissor i receptor i per tant, ha de poder commutar el mode de funcionament per comunicar-se amb un o altres transceptors. La informació es transmet utilitzant una modulació de fase QPSK sobre una portadora de radiofreqüència. A part d'aquesta modulació de fase, la informació està codificada diferencialment. És a dir, que la dada no és directament la fase rebuda en el moment, sinó que la dada és la diferència entre dos fases consecutives. La part receptora està formada per un circuit analògic basat en un receptor super-regeneratiu i una FPGA. Aquest tipus de receptor és de baixa complexitat, baix consum i baix cost. El circuit super-regeneratiu es basa en un oscil'lador que és capaç d'agafar la informació de la fase de la senyal entrant. A partir d'aquesta senyal la FPGA fa un post-processat digital simple per obtenir les fases rebudes. En aquest projecte també s'ha resolt el problema de sincronisme entre un transceptor en mode transmissor i un altre en mode receptor. S'ha creat un preàmbul amb el qual el receptor és capaç de decidir la zona òptima per poder mostrejar les següents dades on hi haurà la informació. La part transmissora s'encarrega de generar les dades que volem transmetre, codificar-les diferencialment i modular-les en QPSK sobre la senyal RF portadora. Tot aquest procés es fa íntegrament en la FPGA, per tant el transmissor és totalment digital. La implementació d'un transceptor utilitzant un receptor super-regeneratiu és un fet força innovador. En aquest cas es treballa amb un senyal de radiofreqüència de 26,25 MHz, però és una prova per verificar el seu correcte funcionament i seria perfectament extrapolable a freqüències més altes

Diseño e implementación de un transceptor super-regenerativo QPSK

[ANGLÈS] This project consists on the design and the implementation of a radio frequency transceiver. A transceiver is a device which is able to be a transmitter and a receiver and, therefore, it is suitable for commuting the working manner in order to communicate to other transceivers. The information is transmitted by a QPSK phase modulation over a radio frequency carrier and a part from this, the information is differentially codified. That means that the data is not directly the received phase at the moment, but it is the difference between two consecutive phases. The received part is made up by an analogical circuit based on a super- regenerative receiver and a FPGA. This type of receiver has a low complexity, low consume, and low cost. The super-regenerative circuit is built of an oscillator able to obtain the information of the entrance sign of the phase. From this signal, the FPGA makes a simple digital post-process in order to obtain the received phases. In this project it has also been solved the synchronism problem between a transceiver on transmitter mode, and another one on receiver mode. It has been created a preamble by which the receiver is able to decide the optimum zone to sample the following data where the information will be in. The transmitting part is in charge of generate the data that we want to transmit, encoding them differentially and modeling them in QPSK over the RF carrier signal. All this process is realized entirely in FPGA, and therefore the transmitter is digital totally. The implementation of a transceiver using a super-regenerative receiver is a quite innovative fact. In this case, the work is mainly produced by a radio frequency sign of 26,25MHz, although it is a prove to verify the correct functioning and it would be perfectly extrapolated to higher frequencies.[CASTELLÀ] Este proyecto consiste en el diseño e implementación de un transceptor de radiofrecuencia. Un transceptor es un dispositivo capaz de ser transmisor y receptor y por lo tanto, ha de poder conmutar el modo de funcionamiento para comunicarse con uno u otros transceptores. La información se transmite utilizando una modulación de fase QPSK sobre una portadora de radiofrecuencia. A parte de esta modulación de fase, la información está codificada diferencialmente. Esto quiere decir que, el dato no es directamente la fase recibida en el momento, sino que éste es la diferencia entre dos fases consecutivas. La parte receptora está formada por un circuito analógico basado en un receptor super-regenerativo y una FPGA. Este tipo de receptor es de baja complejidad, bajo consumo y bajo coste. El circuito super-regenerativo se basa en un oscilador capaz de obtener la información de la fase de la señal entrante. A partir de esta señal la FPGA hace un post-procesado digital simple para obtener las fases recibidas. En este proyecto también se ha resuelto el problema de sincronismo entre un transceptor en modo transmisor y otro en modo receptor. Se ha creado un preámbulo con el cual el receptor es capaz de decidir la zona óptima para poder muestrear los siguientes datos donde habrá la información. La parte transmisora se encarga de generar los datos que se quieren transmitir, codificándolas diferencialmente y modularlas en QPSK sobre la señal RF portadora. Todo este proceso se hace íntegramente en la FPGA, por lo tanto el transmisor es totalmente digital. La implementación de un transceptor utilizando un receptor super-regenerativo es un hecho bastante innovador. En este caso se trabaja con una señal de radiofrecuencia de 26,25 MHz, pero es una prueba para verificar su correcto funcionamiento y sería perfectamente extrapolable a frecuencias más altas.[CATALÀ] Aquest projecte consisteix en el disseny i implementació d'un transceptor de radiofreqüència. Un transceptor és un dispositiu capaç de ser transmissor i receptor i per tant, ha de poder commutar el mode de funcionament per comunicar-se amb un o altres transceptors. La informació es transmet utilitzant una modulació de fase QPSK sobre una portadora de radiofreqüència. A part d'aquesta modulació de fase, la informació està codificada diferencialment. És a dir, que la dada no és directament la fase rebuda en el moment, sinó que la dada és la diferència entre dos fases consecutives. La part receptora està formada per un circuit analògic basat en un receptor super-regeneratiu i una FPGA. Aquest tipus de receptor és de baixa complexitat, baix consum i baix cost. El circuit super-regeneratiu es basa en un oscil'lador que és capaç d'agafar la informació de la fase de la senyal entrant. A partir d'aquesta senyal la FPGA fa un post-processat digital simple per obtenir les fases rebudes. En aquest projecte també s'ha resolt el problema de sincronisme entre un transceptor en mode transmissor i un altre en mode receptor. S'ha creat un preàmbul amb el qual el receptor és capaç de decidir la zona òptima per poder mostrejar les següents dades on hi haurà la informació. La part transmissora s'encarrega de generar les dades que volem transmetre, codificar-les diferencialment i modular-les en QPSK sobre la senyal RF portadora. Tot aquest procés es fa íntegrament en la FPGA, per tant el transmissor és totalment digital. La implementació d'un transceptor utilitzant un receptor super-regeneratiu és un fet força innovador. En aquest cas es treballa amb un senyal de radiofreqüència de 26,25 MHz, però és una prova per verificar el seu correcte funcionament i seria perfectament extrapolable a freqüències més altes

Diseño e implementación de un transceptor super-regenerativo QPSK

[ANGLÈS] This project consists on the design and the implementation of a radio frequency transceiver. A transceiver is a device which is able to be a transmitter and a receiver and, therefore, it is suitable for commuting the working manner in order to communicate to other transceivers. The information is transmitted by a QPSK phase modulation over a radio frequency carrier and a part from this, the information is differentially codified. That means that the data is not directly the received phase at the moment, but it is the difference between two consecutive phases. The received part is made up by an analogical circuit based on a super- regenerative receiver and a FPGA. This type of receiver has a low complexity, low consume, and low cost. The super-regenerative circuit is built of an oscillator able to obtain the information of the entrance sign of the phase. From this signal, the FPGA makes a simple digital post-process in order to obtain the received phases. In this project it has also been solved the synchronism problem between a transceiver on transmitter mode, and another one on receiver mode. It has been created a preamble by which the receiver is able to decide the optimum zone to sample the following data where the information will be in. The transmitting part is in charge of generate the data that we want to transmit, encoding them differentially and modeling them in QPSK over the RF carrier signal. All this process is realized entirely in FPGA, and therefore the transmitter is digital totally. The implementation of a transceiver using a super-regenerative receiver is a quite innovative fact. In this case, the work is mainly produced by a radio frequency sign of 26,25MHz, although it is a prove to verify the correct functioning and it would be perfectly extrapolated to higher frequencies.[CASTELLÀ] Este proyecto consiste en el diseño e implementación de un transceptor de radiofrecuencia. Un transceptor es un dispositivo capaz de ser transmisor y receptor y por lo tanto, ha de poder conmutar el modo de funcionamiento para comunicarse con uno u otros transceptores. La información se transmite utilizando una modulación de fase QPSK sobre una portadora de radiofrecuencia. A parte de esta modulación de fase, la información está codificada diferencialmente. Esto quiere decir que, el dato no es directamente la fase recibida en el momento, sino que éste es la diferencia entre dos fases consecutivas. La parte receptora está formada por un circuito analógico basado en un receptor super-regenerativo y una FPGA. Este tipo de receptor es de baja complejidad, bajo consumo y bajo coste. El circuito super-regenerativo se basa en un oscilador capaz de obtener la información de la fase de la señal entrante. A partir de esta señal la FPGA hace un post-procesado digital simple para obtener las fases recibidas. En este proyecto también se ha resuelto el problema de sincronismo entre un transceptor en modo transmisor y otro en modo receptor. Se ha creado un preámbulo con el cual el receptor es capaz de decidir la zona óptima para poder muestrear los siguientes datos donde habrá la información. La parte transmisora se encarga de generar los datos que se quieren transmitir, codificándolas diferencialmente y modularlas en QPSK sobre la señal RF portadora. Todo este proceso se hace íntegramente en la FPGA, por lo tanto el transmisor es totalmente digital. La implementación de un transceptor utilizando un receptor super-regenerativo es un hecho bastante innovador. En este caso se trabaja con una señal de radiofrecuencia de 26,25 MHz, pero es una prueba para verificar su correcto funcionamiento y sería perfectamente extrapolable a frecuencias más altas.[CATALÀ] Aquest projecte consisteix en el disseny i implementació d'un transceptor de radiofreqüència. Un transceptor és un dispositiu capaç de ser transmissor i receptor i per tant, ha de poder commutar el mode de funcionament per comunicar-se amb un o altres transceptors. La informació es transmet utilitzant una modulació de fase QPSK sobre una portadora de radiofreqüència. A part d'aquesta modulació de fase, la informació està codificada diferencialment. És a dir, que la dada no és directament la fase rebuda en el moment, sinó que la dada és la diferència entre dos fases consecutives. La part receptora està formada per un circuit analògic basat en un receptor super-regeneratiu i una FPGA. Aquest tipus de receptor és de baixa complexitat, baix consum i baix cost. El circuit super-regeneratiu es basa en un oscil'lador que és capaç d'agafar la informació de la fase de la senyal entrant. A partir d'aquesta senyal la FPGA fa un post-processat digital simple per obtenir les fases rebudes. En aquest projecte també s'ha resolt el problema de sincronisme entre un transceptor en mode transmissor i un altre en mode receptor. S'ha creat un preàmbul amb el qual el receptor és capaç de decidir la zona òptima per poder mostrejar les següents dades on hi haurà la informació. La part transmissora s'encarrega de generar les dades que volem transmetre, codificar-les diferencialment i modular-les en QPSK sobre la senyal RF portadora. Tot aquest procés es fa íntegrament en la FPGA, per tant el transmissor és totalment digital. La implementació d'un transceptor utilitzant un receptor super-regeneratiu és un fet força innovador. En aquest cas es treballa amb un senyal de radiofreqüència de 26,25 MHz, però és una prova per verificar el seu correcte funcionament i seria perfectament extrapolable a freqüències més altes

An interdisciplinary approach to motivate students to learn digital systems and computing engineering

We report a new learning approach in collaborative learning-by doing, real-world team-based project in two ICT courses: DigitalSystems and Computing Engineering, conducted at Universitat Polite`cnica de Catalunya. Data collected included: backgroundinformation on students; course evaluations; measures of the knowledge and cross-knowledge of both disciplines taken before andafter our SimulAVR project. SimulAVR integrates interdisciplinary knowledge by simulating via software a microcontroller and itsimplementation in VHDL. Our study is based on the analysis of the results of running the project for 3 years. After taking thesimulAVR project, the students rated the interest in both courses higher.Peer ReviewedPostprint (published version

An interdisciplinary approach to motivate students to learn digital systems and computing engineering

We report a new learning approach in collaborative learning-by doing, real-world team-based project in two ICT courses: DigitalSystems and Computing Engineering, conducted at Universitat Polite`cnica de Catalunya. Data collected included: backgroundinformation on students; course evaluations; measures of the knowledge and cross-knowledge of both disciplines taken before andafter our SimulAVR project. SimulAVR integrates interdisciplinary knowledge by simulating via software a microcontroller and itsimplementation in VHDL. Our study is based on the analysis of the results of running the project for 3 years. After taking thesimulAVR project, the students rated the interest in both courses higher.Peer Reviewe

An interdisciplinary approach to motivate students to learn digital systems and computing engineering

We report a new learning approach in collaborative learning-by doing, real-world team-based project in two ICT courses: DigitalSystems and Computing Engineering, conducted at Universitat Polite`cnica de Catalunya. Data collected included: backgroundinformation on students; course evaluations; measures of the knowledge and cross-knowledge of both disciplines taken before andafter our SimulAVR project. SimulAVR integrates interdisciplinary knowledge by simulating via software a microcontroller and itsimplementation in VHDL. Our study is based on the analysis of the results of running the project for 3 years. After taking thesimulAVR project, the students rated the interest in both courses higher.Peer Reviewe