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Mitigating delay and coupling effects in a high-speed PMSM drive using an optimal multivariable control approachTasnim, Kazi Nishat 10 May 2024 (has links) (PDF)
In this thesis, an optimal multivariable current control method is presented for the highspeed permanent magnet synchronous motor (HS-PMSM). The HS-PMSMs have growing applications in the industry. One of their major challenges is the low switching to fundamental frequency ratio (SFR). At high speed and low SFR, the control time delays including the digital, the PWM, and sensor delays become more pronounced and lead to oscillations and even instabilities. A well-known method for delay compensation is to advance the phase angle of control input for a known amount. In practice, the exact delay is unknown, and mismatch in the compensating angle causes deteriorating effect on the system. In the proposed method, the digital and PWM delays are modelled and integrated with an optimal multivariable controller. This method improves the stability margin and achievable speed margin compared to the traditional phase advancing delay compensation (PADC) method. Combining the proposed delay modeling and the PADC method further improves the response, as the uncertain sensor delays can be compensated greatly. Besides the delay, the cross-coupling between ���� axis affects the dynamic performance of the machine. The proposed multivariable approach considers and directly addresses the coupling. Dynamic performance of the PMSM with the proposed method is thoroughly compared with the conventional delay compensation method. The proposed method is validated through extensive simulation studies on a 2 kW high-speed machine.
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Controllerrollen och dess utveckling : En kvalitativ studie / The role of the controller and its development : A qualitative studyDikander, Linnea, Karlsson, Hanna January 2024 (has links)
Denna kvalitativa studie syftar till att undersöka hur yrkesrollen controller har utvecklats men även hur den utvecklas i framtiden. Detta har studerats med hjälp av professionsteorin där utgångspunkten är att undersöka hur professionaliseringen av controllerns yrkesroll ser ut. Studien utgår från ett strategiskt urval eftersom att studien grundar sig i en specifik yrkesroll. Urvalet innefattar tolv respondenter från sju olika företag där alla respondenter har eller arbetar som controller. För att undersöka syftet har studien utgått från en analysmodell med sex specifika professionskriterier. Studien utgår utifrån en induktiv ansats. Studien visar att yrkesrollen befinner sig i en förändringsfas och håller på att utvecklas bort från sin ursprungliga definition och innebörd. Yrkesrollen utvecklas främst i takt med teknologin och hållbarheten men även i regulatoriska krav. Studien indikerar att controllern i nuläget inte kan identifieras som en profession men i takt med utvecklingen går yrkesrollen mer mot en profession. I nuläget kan den ses mer som en semiprofession eller pre profession. Tidigare forskning har lagt stort fokus på att identifiera vilken utveckling yrkesrollen står inför, där teknologin har varit en utstickande faktor. I denna studie ansågs det vara av betydelse att studera vilka utvecklingsfaktorer som en controller möter i praktiken, samt hur och på vilket sätt teknologin har implementeras i deras roll. Vidare finns det inte någon tydlig forskning kring controller som profession i förhållande till utvecklingsfaktorer vilket denna studie även ska bidra med. Studiens förslag till framtida forskning är en bredare urvalsgrupp samt en mer djupgående studie där observationer även förekommer. / This qualitative study aims to investigate how the role of the controller has but also how it develops in the future. The starting point of the study is to investigate how the professionalization of the controller role looks like. This will be studied with the help of the profession theory. The study is based on the strategic sample because it is based on a specific role, in this case the controller. The sample includes twelve respondents from seven different companies where all the respondents have or work as a controller. To investigate the purpose, the study has been based on an analysis model with six specific profession criteria. The study is based on an inductive approach. The study shows that the controller is in a phase of a change and is evolving away from its original definition and meaning. The controller is evolving mainly in line with technology and sustainability but also in regulatory requirements. The study indicates that the controller cannot be identified as a profession at present but as it develops the role is moving more toward a profession. At present it can be seen more as a semiprofession or preprofession. Previous research has great emphasis on identifying the developments facing the role, where technology has been an outlying factor. In this study, it was considered important to study which development factors that a controller encounters in practice, as well as how and in what way technology has been implemented in their role. Furthermore, there is no clear research on the controller as a profession in relation to development factors, which this study will also contribute to. The studies proposal for future research is a broader sample group and more in-depth study that also includes observations. Furthermore, this study is conducted in swedish.
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Análise, desenvolvimento e controle de uma plataforma de movimentos com 6 graus de liberdade / Analysis, development and control of a platform of movements with 6 degrees of freedomBreganon, Ricardo 19 May 2014 (has links)
Nos últimos anos, tem havido grande interesse em estudar manipuladores paralelos, aplicados principalmente em simuladores de voo, com seis graus de liberdade. O interesse em estruturas cinemáticas paralelas é motivado por sua alta rigidez e excelente capacidade de posicionamento em relação às estruturas cinemáticas seriais. Além disso, como os atuadores são posicionados em uma base, eles podem ser aplicados em cargas pesadas e ainda apresentam baixo consumo de energia, tendo em vista que vários atuadores atuam simultaneamente no mesmo corpo. A presente tese apresenta o projeto de três controladores, sendo eles, o controlador H infinito com realimentação de saída, o controlador PID e o controlador Fuzzy, com isto, esta metodologia poderá ser empregada na construção de um futuro simulador de voo. O modelo dos atuadores foi obtido através de uma entrada degrau de tensão nos motores, medindo os seus deslocamentos através dos encoders acoplados, individualmente, a cada um dos respectivos eixos dos motores. Sabendo-se a relação de transmissão do mecanismo de movimento entre o motor e cada haste dos atuadores obtém-se o deslocamento de cada haste a partir da rotação de cada motor medida pelo correspondente encoder e com isso obtém-se o modelo matemático de cada atuador em conjunto com seu sistema de transmissão. Entretanto, na prática, cada atuador é ligeiramente diferente dos outros, o que leva a comportamento e desempenho diferentes entre si. Isso afeta o comportamento da plataforma fazendo com que a trajetória final desejada não possa ser seguida adequadamente, algo que é extremamente necessário em simuladores de voo. Assim, uma das contribuições importantes deste trabalho é, em primeiro lugar, apresentar uma metodologia de padronização das respostas dos atuadores de modo a que todos eles tenham no final, um comportamento igual o mais próximo possível, particularmente em termos de velocidade e de posicionamento. Com os dados da cinemática e da dinâmica da plataforma compondo o modelo completo do sistema foram realizadas várias simulações que aplicadas na plataforma de Stewart real validaram o modelo e mostraram a eficiência das técnicas de controle aplicadas no controle de posição e orientação da plataforma. Para validar o projeto da Plataforma de Stewart como uma possível base de movimento de um simulador de voo, foi implementada a dinâmica longitudinal e lateral de um Boeing 747-100, e com o auxilio de um sensor inercial Xsens® MTi-G, foram realizadas as medições dos ângulos de Euler da Plataforma. Os resultados obtidos pelos três controladores foram satisfatórios e ilustram o desempenho e a robustez da metodologia proposta. / In recent years there has been great interest in studying parallel manipulators, mainly applied in flight simulators, with six degrees of freedom. The interest in parallel kinematic structures is motivated by its high stiffness and excellent positioning capability in relation to serial kinematic structures. Furthermore, since the actuators are positioned on a base, they can handle heavy loads and also have low power consumption, considering that several actuators act on the same platform. This thesis presents the design of three controllers, which are, H-infinity controller with output feedback, PID controller and Fuzzy controller, so that this methodology can be employed in building a future flight simulator. The actuators models were obtained by a step voltage input to the engines and measuring their displacements by the encoders that are coupled to each of the respective axes of the motors. Knowing the relation from the motion transmission mechanism between the motor and the spindle of each actuator, the displacement of each spindle is obtained from the rotation of each motor measured by the corresponding encoder and thus we obtain the mathematical model of each actuator together with its transmission system. However, in practice, each actuator is slightly different from others, which leads to different behavior and performance of each. This affects the behavior of the platform making the final desired trajectory cannot be properly followed something that is extremely necessary in flight simulators. Thus, one of the important contributions of this work is first to present a methodology to standardize the actuators responses so that they all have in the end a behavior equal a close as possible, particularly in terms of velocity and positioning. With the kinematics data and platform dynamics composing the complete system model, several simulations applied to the real Stewart Platform validate the model and show the effectiveness of control techniques applied to control the position and orientation of the platform. In order to validate the Stewart Platform design as a possible base for a motion flight simulator, the longitudinal and lateral dynamics of a Boeing 747-100 model were implemented, and with the aid of an inertial sensor Xsens® MTi-G, measurements of the Euler angles of the platform were performed. The results obtained by the three controllers were satisfactory and illustrate the performance and robustness of the proposed methodology.
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Experience Mapping based Prediction ControllerSaikumar, Niranjan January 2015 (has links) (PDF)
A novel controller termed as Experience Mapping based Prediction Controller (EMPC) is developed in this work. EMPC is developed utilizing the broad control concepts of human motor control (HMC). The concepts of HMC are utilized to develop the core concepts of EMPC for the control of ideal Type-1 LTI systems. The control accuracy of the developed concepts is studied and the mathematical stability criterion for the controller is developed. The applicability of EMPC for the control of real world problems is tested on a Permanent Magnet DC motor based position control system.
1. Novel learning methods are presented to form experience mapped knowledge-base (EMK) which is used for the creation of the forward and inverse models.
2. Control and Adaptation Techniques which overcome the presence of non idealities are developed using the inverse model.
3. Two separate techniques which utilize the forward model for improving the adaptation capabilities of EMPC are developed.
4. Two novel techniques are developed for the improvement of the tracking performance in terms of the accuracy and smoothness of tracking.
These techniques are tested under various system conditions including large dynamic parameter changes on a simulation model and a practical setup. The performance of EMPC is compared against that of PID, MRAC and LQG controllers for all the proposed techniques and EMPC is found to perform significantly better under the various system conditions in terms of transient and steady state characteristics.
Finally, the effectiveness of EMPC in stabilizing unstable systems using the concepts developed is tested on a practical Inverted Pendulum system. The problem of the simultaneous development of experiences and control of the system is addressed with the stabilizing problem.
The proposed controller, EMPC provides an alternative approach for the existing control of systems without the requirement of an accurate system mathematical model. Its capability to learn by directly interacting with the system and adapt using experiences makes it an attractive alternative to other control techniques present in literature.
Keywords: EMPC, Position Control, PMDC motors
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Análise, desenvolvimento e controle de uma plataforma de movimentos com 6 graus de liberdade / Analysis, development and control of a platform of movements with 6 degrees of freedomRicardo Breganon 19 May 2014 (has links)
Nos últimos anos, tem havido grande interesse em estudar manipuladores paralelos, aplicados principalmente em simuladores de voo, com seis graus de liberdade. O interesse em estruturas cinemáticas paralelas é motivado por sua alta rigidez e excelente capacidade de posicionamento em relação às estruturas cinemáticas seriais. Além disso, como os atuadores são posicionados em uma base, eles podem ser aplicados em cargas pesadas e ainda apresentam baixo consumo de energia, tendo em vista que vários atuadores atuam simultaneamente no mesmo corpo. A presente tese apresenta o projeto de três controladores, sendo eles, o controlador H infinito com realimentação de saída, o controlador PID e o controlador Fuzzy, com isto, esta metodologia poderá ser empregada na construção de um futuro simulador de voo. O modelo dos atuadores foi obtido através de uma entrada degrau de tensão nos motores, medindo os seus deslocamentos através dos encoders acoplados, individualmente, a cada um dos respectivos eixos dos motores. Sabendo-se a relação de transmissão do mecanismo de movimento entre o motor e cada haste dos atuadores obtém-se o deslocamento de cada haste a partir da rotação de cada motor medida pelo correspondente encoder e com isso obtém-se o modelo matemático de cada atuador em conjunto com seu sistema de transmissão. Entretanto, na prática, cada atuador é ligeiramente diferente dos outros, o que leva a comportamento e desempenho diferentes entre si. Isso afeta o comportamento da plataforma fazendo com que a trajetória final desejada não possa ser seguida adequadamente, algo que é extremamente necessário em simuladores de voo. Assim, uma das contribuições importantes deste trabalho é, em primeiro lugar, apresentar uma metodologia de padronização das respostas dos atuadores de modo a que todos eles tenham no final, um comportamento igual o mais próximo possível, particularmente em termos de velocidade e de posicionamento. Com os dados da cinemática e da dinâmica da plataforma compondo o modelo completo do sistema foram realizadas várias simulações que aplicadas na plataforma de Stewart real validaram o modelo e mostraram a eficiência das técnicas de controle aplicadas no controle de posição e orientação da plataforma. Para validar o projeto da Plataforma de Stewart como uma possível base de movimento de um simulador de voo, foi implementada a dinâmica longitudinal e lateral de um Boeing 747-100, e com o auxilio de um sensor inercial Xsens® MTi-G, foram realizadas as medições dos ângulos de Euler da Plataforma. Os resultados obtidos pelos três controladores foram satisfatórios e ilustram o desempenho e a robustez da metodologia proposta. / In recent years there has been great interest in studying parallel manipulators, mainly applied in flight simulators, with six degrees of freedom. The interest in parallel kinematic structures is motivated by its high stiffness and excellent positioning capability in relation to serial kinematic structures. Furthermore, since the actuators are positioned on a base, they can handle heavy loads and also have low power consumption, considering that several actuators act on the same platform. This thesis presents the design of three controllers, which are, H-infinity controller with output feedback, PID controller and Fuzzy controller, so that this methodology can be employed in building a future flight simulator. The actuators models were obtained by a step voltage input to the engines and measuring their displacements by the encoders that are coupled to each of the respective axes of the motors. Knowing the relation from the motion transmission mechanism between the motor and the spindle of each actuator, the displacement of each spindle is obtained from the rotation of each motor measured by the corresponding encoder and thus we obtain the mathematical model of each actuator together with its transmission system. However, in practice, each actuator is slightly different from others, which leads to different behavior and performance of each. This affects the behavior of the platform making the final desired trajectory cannot be properly followed something that is extremely necessary in flight simulators. Thus, one of the important contributions of this work is first to present a methodology to standardize the actuators responses so that they all have in the end a behavior equal a close as possible, particularly in terms of velocity and positioning. With the kinematics data and platform dynamics composing the complete system model, several simulations applied to the real Stewart Platform validate the model and show the effectiveness of control techniques applied to control the position and orientation of the platform. In order to validate the Stewart Platform design as a possible base for a motion flight simulator, the longitudinal and lateral dynamics of a Boeing 747-100 model were implemented, and with the aid of an inertial sensor Xsens® MTi-G, measurements of the Euler angles of the platform were performed. The results obtained by the three controllers were satisfactory and illustrate the performance and robustness of the proposed methodology.
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Servomotor s elektronickou komutací, jeho řízení a nastavování. / Servomotor with electronic commutating and his control and adjusting.Schmied, Miloš January 2009 (has links)
This thesis deals with the analysis of the actuator ACOPOS and its accessories. There are described the cascaded control loop concept and the setting servomechanism from B&R Automation with the important parameters. We follow the draft a speed controller servomotor with a load with the regards to knowledge of the control system. We compare the different methods of labor control actuator at last. There are implemented laboratory tasks of Position servomechanism and speed servo controller-on-load as a demonstration of our achieved results.
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Ekonomistyrning utan budget : Controllern och budgetering i kontrast till Beyond budgeting / Management control without budgets : The controller and budgeting in contrast to Beyond budgetingWadström, Samuel, Engstrand, Erik January 2020 (has links)
Bakgrund: Konventionell budgetering har fått utstå betydande kritik under de senaste decennierna, där många menar att den inte är lämplig i dagenssnabbrörliga och globala marknad. Ett flertal organisationer har övergett konventionell budgetering, och rörelsen eller filosofin berördetta kallas för Beyond Budgeting (BB). Grundprinciperna i denna filosofi är en organisationsstruktur där mer ansvar och tillit placeras hos den operativa delen av organisationer. Detta är menat att ge mer frihet till enskilda medarbetare men väcker frågor om agentteori och organisatorisk kontroll. Controllers traditionella roll har setts som ett verktyg för ledningen att utöva kontroll och motverka agentteorins moraliskarisk. Frågan är hur denna roll påverkas av en allt mindre strikt form av kontroll, vilka faktorer som kan tänkas påverka denna roll och hur rollen redan har förändrats. Syfte: Studiens syfte är att undersöka hur controllerrollen och budgetarbete ser ut i dagens organisationer samt om kritiken mot budgetarbete, så som filosofin BB beskriver den, faktiskt stämmer i dagens organisationer. Ytterligare undersöker studien till vilken grad BB som metod har implementerats i dessa organisationer. Metod: Semi-strukturerade intervjuer med sex stycken respondenter inom flertalet olika organisationer har agerat som empirisk data. Denna data harsedantranskriberats och analyserats i enlighet med den deduktiva ansatsen, där de teorier vi funnit har applicerats. Analysen skedde genom en tematisk analys där teman och kategorier funnits för att påvisa samband inför slutsatsen. Slutsats: Studien tyder på att controllers idag har en hög grad av kontroll över deras arbete samt att arbetet huvudsakligen är analytiskt och framåtblickande. Delar av respondenterna anser sig ha en beslutsfattande roll och arbetar huvudsakligen enskilt men har ett brett kontaktnät. Rollen kan till viss del beskrivas som en affärspartner men vi fann stora skillnader mellan respondenterna. Bland respondenterna var det vanligast att använda en toppstyrd budget, där enskilda affärsenheter har mindre inflytande. Denna budget kompletterades sedan med prognoser. Vi fann att delar av kritiken mot konventionell budgetering stämde in bland respondenternas organisationer, samt att aspekter av BB har implementerats. / Background: Conventional budgeting has endured a lot of criticism in the last decades as many argue it is not suitable for today's agile and globalized market. Several organizations have taken the step to abandon conventional budgeting and the movement, or philosophy, regarding this matter is known as Beyond Budgeting (BB). The core principle of this philosophy are an organizational structure where a higher degree of responsibility and trust is placed on the operative sections of the organization. By doing this a much higher degree of liberty is granted to partners in the organization, but it raises questions regarding agent theory and organizational control. The traditional role of the controller has been to function as a tool for upper management to exercise control and counteract the moral hazard of agency theory. The question then is how this role is affected by a much less strict form of control, and which factors can be seen to affect the role as well as which factors that have already affected it. Purpose: The purpose of the study is to examine the role of the controller and how budgeting of modern organizations are handled as well as how the accurate the critique aimed at budgeting is, as it is described by the philosophy of BB. Furthermore, the study aims to examine to which degree the subject organizations has implemented or embraced the principles of BB. Method: The study is built on semi-structured interviews with a total of six participants, based in several organizations, which have acted as the empirical data. This data has been transcribed and analyzed in accordance with the studies’ deductive approach upon which our studied theories have been applied. The analysis has been based on a thematic analysis where the goal has been to find common themes and categories. Conclusion: The study has found that controllers today have a high degree of control regarding how they choose to perform their work, which has been found to be primarily analytical and forward-looking in nature. Some of the controllers consider themselves to have a decision-making role, and while their work is primarily done alone, they have a wide array of contacts. The role can to a degree be described as a business partner, but the study has found large differences among participants in this regard. Among the participants it was most common to use a conventional budget, set by upper management where local business units have limited influence. This budget was complemented with forecasts. The study also found that among the participant’s organizations, some of the critique towards conventional budgeting was accurate to a certain degree. In addition, we found that aspects of BB had been implemented.
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Controller - En Förändrad Yrkesroll : En Kvalitativ Studie Om Informationsteknologins Påverkan På Rollen / Controller - A Changed Professional Role : A Qualitative Study Of Information Technology's Impact On The RoleJohansson, Alicia, Uneram, Emma January 2024 (has links)
Bakgrund: Digitaliseringen och den informationstekniska utvecklingen har bidragit till förändrade arbetsuppgifter för många yrkesgrupper. Denna uppsats har valt att fokusera på yrkesgruppen controllers och hur utvecklingen har påverkat deras arbetsuppgifter. Utvecklingen av IT-systemen, Business Intelligence (BI) och Artificiell Intelligens (AI), anses ha en betydande inverkan på controllern då de förändrar arbetsuppgifter som i sin tur påverkar controllerrollen. Syfte: Uppsatsens syfte är att förstå hur informationsteknologins utveckling har påverkat controllerns arbetsuppgifter. Detta för att skapa en bredare förståelse för hur förändringar i arbetsuppgifterna i sin tur påverkar controllerrollen. Dessutom kommer utmaningar och möjligheter med användandet av IT-system att identifieras, med utgångspunkt i två olika system. Metod: För att uppfylla uppsatsens syfte har en kvalitativ metod använts där sex semistrukturerade intervjuer med controllers har genomförts. Studien har tagit en abduktiv forskningsansats vid genomförandet av intervjuerna. Resultat: Studien resulterade i att controllerns arbetsuppgifter har utökats i takt med informationsteknologins utveckling. Controllern ägnar sig idag åt mer stödjande aktiviteter, vilket i sin tur har utvecklat controllerns roll till att ses som en affärspartner. IT-system har främst möjliggjort för effektivitet i controllerns arbete med datahantering och dataanalys, men det finns även några utmaningar som informationsteknologin har medfört. / Background: The digitalisation and development of information technology have contributed to changed tasks for many professions. This essay will focus on the profession of controllers and how these developments have affected their tasks. The development of the IT-systems, Business Intelligence (BI) and Artificial Intelligence (AI), are considered to have a significant impact on the controller as they change tasks, which in turn affects the controller role. Purpose: The purpose of this study is to understand how the development of information technology has made an impact on the tasks of controllers. This aims to provide a broader understanding of how changes in these tasks, in turn, affect the role of the controller. Additionally, challenges and opportunities associated with the use of IT-systems will be identified, based on two different systems. Method: To fulfill the purpose of the essay, a qualitative method has been used, involving six semi-structured interviews with controllers. This study adopted an abductive approach when conducting the interviews. Conclusion: The study found that the responsibilities of controllers have expanded in line with the development of information technology. Today, controllers are more engaged in supportive activities, which in turn has evolved the controller's role to be seen as a business partner. IT-systems have primarily facilitated efficiency in the controller´s tasks related to data management and data analysis, but there are also some challenges that information technology has caused.
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Controllerns roll i olika kommunala förvaltningar : En fallstudie från Växjö kommun / The role of the controller in different municipal administrations : A case study from Växjö municipalitySaydi, Julia, Ebrahim, Ana January 2024 (has links)
Bakgrund och problemformulering: Controllerrollen har genomgått stora förändringar sedan 1900-talet och studerats ur olika perspektiv. Rollen som controller påverkas av ett antal faktorer bland annat politiska faktorer. Tidigare visar att forskning saknas kring hur controllern arbetar inom offentlig sektor samt hur dess arbetsuppgifter och ansvar påverkas av offentlig ledning. Syfte: Studiens syfte är att undersöka hur controllern arbetar inom den offentliga sektorn och påverkas av offentlig ledning. Detta kommer att utföras genom att identifiera controllers arbetsuppgifter och ansvar samt hur rollen skiljer sig mellan de olika kommunala förvaltningarna. Metod: Denna studie är en kvalitativ undersökning och har utgått från ett induktivt angreppssätt. Det empiriska materialet har genererats med hjälp av semistrukturerade intervjuer med controllers från Växjö kommun. Insamling av ytterligare data i övriga delar har skett genom vetenskapliga artiklar, relevant litteratur och trovärdiga webbsidor. Slutsats: Controllers i Växjö kommun har samma roll i grunden men deras arbetsuppgifter samt ansvar skiljer sig beroende på vilken förvaltning de tillhör. Skillnaderna beror dels på centraliseringen och införandet av titeln ‘’controller’’ i kommunen. Exempel på skillnader är rapporteringar, ansvarsområden och resursfördelningar. / Background and problem statement: The controller role has undergone significant changes since the 20th century and has been studied from various perspectives. The role is influenced by several factors, including political ones. Previous research shows a lack of studies on how controllers work in the public sector and how tasks and responsibilities are affected by public management. Purpose: The purpose of the study is to examine how controllers operate within the public sector and are influenced by public administration. This study will also bestow knowledge regarding how a controller in the public sector contributes to the maintenance of welfare. Method: This study is a qualitative research method with a inductive approach. The empirical data has been collected through semi-structured interviews with the controllers from Växjö municipality. Conclusion: The controllers in Växjö municipality have fundamentally the same role, but their duties and responsibilities differ depending on which administration they belong to. The differences are partly due to centralization and the introduction of the title "controller" in the municipality. Examples of differences are the reporting, areas of responsibility and resource allocations.
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APPROACH FOR A WIDE DEVIATION RF PHASE MODULATOR on a 6U-VME-CARDWeitzman, Jonathan M 10 1900 (has links)
International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / A Phase Modulator combining digital techniques with non-traditional analog circuitry can minimize the shortcomings of a traditional (purely analog) Phase Modulator. These shortcomings are: nonlinear response from input modulating signal to output modulated signal; parameters (frequency and modulation index) that are difficult to set; and the need for complex filters. The design approach discussed in this paper uses a combination of Direct Digital Synthesis (DDS) and analog devices operating in their linear range to generate a Phase Modulated RF (140 MHz) signal. A Numerically Controlled Oscillator (NCO) digitally generates the first IF yielding a very accurate, repeatable and linear signal with easily adjustable parameters such as frequency and modulation index. Linear multipliers (instead of saturated diode mixers or step recovery diodes) are used for up-conversion to RF. Using linear multipliers eases the filtering requirements due to the significantly reduced harmonics and IM (Inter-Modulation) terms. The resulting RF signal is easily translated to higher frequency bands such as L, S, C, X or K.
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