Добірка наукової літератури з теми "Sinusoidal signal generator"

One of the important tasks of electronic instrumentation is the creation of powerful measuring generators of a sinusoidal signal, in particular, fictitious power generators for testing and verifying electricity meters. Such generators are usually digitally controlled. Get a high efficiency allows pulse-width modulation (PWM). However, when building a device based on PWM, there is a need to suppress higher-order harmonics. To simplify signal filtering, the switching frequency of the keys in the generator is increased, which reduces its efficiency. The paper presents a new method for obtaining a sinusoidal signal by adding three rectangular pulse signals having the frequency of the generated sinusoid, which makes it possible to suppress the 3rd harmonic and filter the harmonics starting from the 5th. This method allows, with high efficiency and a simple output filter, to form a sinusoid with a frequency of not only 50 Hz, but also significantly higher.

An ELT is a beacon indicating the location of distress or crash of aircraft on land or sea. The ELT is placed in an airplane, which is a transmitter with low transmit power and an antenna. The ELT transmitter has been widely used for flights at the frequency of 121.5 MHz (civilian) and 243 MHz (military). The purpose of this study is to produce ELT signal generators at the 121.5 MHz frequency, with low-cost devices that meet specifications for civil aviation. In this research has been produced a design of an ELT signal generator at the frequency of 121.5 MHz, consist of a crystal oscillator, a sawtooth generator, a VCO, and an amplitude modulator. Based on the measurement and test results, the sawtooth generator generated a sawtooth signal at the frequency of 1.8 to 3.6 Hz, the VCO generated a sinusoidal signal at the frequency of 316 to 366 Hz, the RF generator generated a sinusoidal at the frequency of 121.505 MHz. The ELT signal generator was able to generate AM signals at the minimum amplitude deviation of 100 mVpp to maximum one of 156 mVpp, the modulation index (m) of 21.875%, and the frequency of 121.505 MHz. The results of this study are ELT signal generators at the frequencies of 121.5 MHz that are in accordance with specifications for civil aviation.

Sinusoidal signal generator is common electronic equipment. In this paper, the writer designed a kind of integrated CMOS sine signal generator, which generator uses wien bridge oscillation circuit.This generator circuit mainly constitutes by amplifier, leveled and low-pass filter circuit, which uses Cadence software to simulate and analysis its amplification circuit, in order to get a sine wave which has high performance accuracy and stability. Through simulating this generator, we can get a kind of sine wave which includes the frequency as the 1.109 kHz, the center potential as 2.5V, the amplitude as 2.58V, distortion is less than 2%, and this sine wave is more practical for the lower voltage supply system.

The problems of identifying the frequency and parameters of multi-sinusoidal signals with constant parameters are considered in finite time. The signal is represented as the output of a linear generator, where the parameters of the sinusoidal signal (amplitude, phase, and frequency) are unknown. The main idea is to apply the Jordan waveform and lag to parameterize the signal and obtain a linear regression model. Unknown parameters are estimated using DREM method. The performance of algorithms considered in the article is illustrated by computer modeling. Our main contribution is to propose a new approach for parameterization of multisinusoidal signals and finite time parameter estimation.

Low-power A.C. generators of square-wave or sinusoidal signals can be used in combination with impedimetric sensors to detect stimuli on the basis of the voltage drop taking place at the sensor electrodes. When a.c. generators with a power of only a few µ-Watts are used, this approach becomes extremely sensitive. A very low-power generator is the LCD back panel driving signal, which has a flipping polarity with a voltage of 3-5Vpp, depending on the generator model. This type of square-wave generator is contained in many low-cost handheld digital multimeters, and it is used as signal tracer to test, for example, low-frequency amplifiers. As an example, this method has been used to acquire a human breath rate pattern, by using a zeolite-based water sensor. If the generator I-V characteristics has been measured, the achieved breath pattern can be converted from a voltage drop vs. time graph to an impedance or current intensity vs. time graph.

Low-power A.C. generators of square-wave or sinusoidal signals can be used in combination with impedimetric sensors to detect stimuli on the basis of the voltage drop taking place at the sensor electrodes. When a.c. generators with a power of only a few µ-Watts are used, this approach becomes extremely sensitive. A very low-power generator is the LCD back panel driving signal, which has a flipping polarity with a voltage of 3-5Vpp, depending on the generator model. This type of square-wave generator is contained in many low-cost handheld digital multimeters, and it is used as signal tracer to test, for example, low-frequency amplifiers. As an example, this method has been used to acquire a human breath rate pattern, by using a zeolite-based water sensor. If the generator I-V characteristics has been measured, the achieved breath pattern can be converted from a voltage drop vs. time graph to an impedance or current intensity vs. time graph.

This paper presents a very versatile multifunction signal generator tool. The proposed generator is based on State Controlled Cellular Neural Network (SC-CNN) based Chua's circuit and it has two signal generation modes, namely CM (Chaos Mode) and FM (Function Mode). While the generator is able to produce nonlinear chaotic waveforms in Chaos Mode, it is also able to generate other classical sinusoidal, triangle and square waveforms in Function Mode. The proposed design idea has been validated through computer simulations and laboratory experiments. Future studies with the proposed generator tool will contribute to further developments in SC-CNN based engineering applications.

Les techniques d'autotest intégré (BIST) jouent un rôle important dans les circuits analogiques, à signaux mixtes et RF (AMS-RF) afin d'améliorer le rendement des processus nanométriques avancés. Ces circuits remplacent les testeurs AMS-RF très sophistiqués et coûteux. Le générateur de stimuli est l'un des blocs importants des circuits BIST AMS-RF. En particulier, de nombreux tests analogiques-RF nécessitent un signal sinusoïdal de haute qualité comme stimuli de test. L'objectif de cette thèse est de comprendre les défis posés par la génération d'un signal sinusoïdal dans la gamme des GHz et d'atténuer ces défis en utilisant le principe d'annulation harmonique. Dans le principe d'annulation harmonique, un ensemble de signaux périodiques décalés dans le temps sont mis à l'échelle et ajoutés. Dans ce processus, les harmoniques du signal périodique sont annulées et la fréquence fondamentale est conservée à la sortie. Dans ce cas particulier, un générateur de signaux capable d'annuler les harmoniques inférieures à la 11e harmonique est nécessaire. Malgré son efficacité, cette technique est très sensible à la dégradation des performances en raison de l'inadéquation et des variations de processus. Ces variations affectent le décalage temporel et le rapport cyclique (également appelés imprécisions temporelles) du signal, en particulier dans les applications à haute fréquence où un contrôle précis devient de plus en plus difficile. Pour y remédier, une nouvelle architecture d'étalonnage utilise un mécanisme de cellule de retard grossier-fin, qui atténue efficacement l'impact des imprécisions temporelles. L'une des solutions proposées a été fabriquée en utilisant la technologie FDSOI 28 nm de ST et validée. Les résultats des mesures montrent un SFDR supérieur à 60dBc pour des fréquences supérieures à 1 GHz après optimisation, illustrant le potentiel de notre architecture dans l'amélioration de la fiabilité et de l'efficacité de la génération de signaux sinusoïdaux sur la puce pour les circuits intégrés AMS-RF
Built-in self-test (BIST) techniques play an important role in Analog, Mixed-signal, and RF (AMS-RF) circuits so that the yield in advanced nanometric processes can be improved. These circuits replace highly sophisticated and expensive AMS-RF testers. The stimuli generator is one of the important blocks in AMS-RF BIST circuits. In particular, many analog-RF tests require a high-quality sinusoidal signal as test stimuli. The focus of this thesis is to understand the challenges of generating a sinusoidal signal in GHz range and mitigating these challenges using the harmonic cancellation principle. In harmonic cancellation principle, a set of time-shifted periodic signals are scaled and added. In this process, harmonics of the periodic signal are cancelled and the fundamental frequency is retained at the output. Particularly in this case, a signal generator that can cancel the harmonics below the 11th harmonic. Despite its efficiency, this technique is highly susceptible to performance degradation due to mismatch and process variations. These variations affect time-shift and the duty cycle (also called timing inaccuracies) of the signal, particularly in high-frequency applications where precise control becomes increasingly challenging. To address this, a novel calibration architecture employs a coarse-fine delay cell mechanism, which effectively mitigates the impact of timing inaccuracies. One of the proposed solutions was fabricated using ST 28-nm FDSOI technology and validated. The measurement results show an SFDR greater than 60dBc for frequencies greater than 1 GHz after optimization, illustrating the potential of our architecture in enhancing the reliability and effectiveness of on-chip sinusoidal signal generation for AMS-RF integrated circuits

The aim of this thesis is to realise a low-cost wireless application for short range underwater communications, using ultrasonic frequencies. The project can be described in four main steps. The first one is a detailed study of the serial peripheral interface. It has been carried out in order to understand how to physically and logically connect, through SPI, the hardware involved in this work: a Raspberry Pi 3 model B and the MCP4822 digital to analog converter embedded in the ADC-DAC Pi Zero module. The second phase concerns a Simulink model created in order to reduce the complexity of the problem. It has been useful as a guideline for the development of the software. Then, the implementation step includes the full execution of the code, which processes information data and digital samples of a sine wave and converts them in their respective analog signals. Configurable parameters, as the amplitude and the frequency of the sinusoidal carrier, provide more flexibility to the system. The last testing phase consists in several measurements on the hardware to assess the reliability of the system, varying some parameters and comparing these results with the simulations, run on Simulink. The overall performance respects the low-cost nature of the Raspberry Pi: the analog signals exhibit phase noise due to the not perfect periodicity of the SPI clock but they are still reliable and clear enough for project purposes.

Motion control is required in large number of industrial and domestic applications like transportation systems, textile mills, fans, pumps etc. Systems employed for motion control are “Drives”. With the advancement of power electronics, microprocessors and digital electronics, typical electric drive systems nowadays are becoming more compact, efficient, cheaper and versatile. Controllers for Power Modulator is built in Control Unit which usually operates at much lower voltage and power levels. In addition to operating Power Modulator as desired, it may also generate commands for the protection of Power Modulator and Motor. Input command signal, which adjusts the operating point of the drive, forms an input to the Control Unit. In this project, “ARDUINO” is used as a control unit to generate PWM signals to control Power Modulator. A code for the SPWM signal is developed in Arduino software.

Στόχος της παρούσας διπλωματικής εργασίας είναι η τροφοδοσία ενός μεταβαλλόμενου RL φορτίου από μια φωτοβολταϊκή γεννήτρια, επιδιώκοντας η τάση σε αυτό να είναι σταθερή κατά μέτρο και συχνότητα. Η επίτευξη του στόχου προϋποθέτει την χρήση μιας σειράς διατάξεων, προκειμένου να δημιουργήσουμε ένα πειραματικό σύστημα πάνω στο οποίο θα αναπτύξουμε την εφαρμογή μας. Έτσι η πειραματική μας διάταξη εκτός από την πηγή (φωτοβολταϊκή γεννήτρια) και το φορτίο αποτελείται και απο έναν τριφασικό αντιστροφέα πηγής τάσης, έναν τριφασικό μετασχηματιστή, ένα βαθυπερατό φίλτρο LC, μια συσκευή βηματικής μεταβολής του φορτίου και έναν μικροεπεξεργαστή με την βοήθεια του οποίου θα υλοποιήσουμε τους απαραίτητους ελέγχους. Το πρώτο επίπεδο ελέγχου αφορά τον τριφασικό αντιστροφέα και συγκεκριμένα την παλμοδότηση την διακοπτικών του στοιχείων. Με την βοήθεια του μικροεπεξεργαστή πετυχαίνουμε την υλοποίηση του κυκλώματος παλμοδότησης εφαρμόζοντας την μέθοδο της ημιτονοειδούς διαμόρφωσης εύρους παλμών (Sinusoidal Pulse Width Modulation, SPWM). Σε δεύτερο επίπεδο ελέγχου υλοποιούμε έναν PI ελεγκτή ο οποίος σε συνεργασία με το κύκλωμα παλμοδότησης εξασφαλίζει την σταθεροποίηση της τάσης στο φορτίο, συνεπώς και την αδιάλειπτη τροφοδοσία του. Πραγματοποιώντας βηματικές αλλαγές στο φορτίο, καταγράφουμε τις μεταβολές στα μεγέθη εκείνα που επιβεβαιώνουν την λειτουργία και αποδοτικότητα του συνολικού συστήματος ελέγχου. Ιδιαίτερη αξία έχει ο τρόπος με τον οποίο παράγουμε τον κώδικα που υλοποιεί, μέσω του μικροεπεξεργαστή, το κύκλωμα ελέγχου. Η διαδικασία περιλαμβάνει αρχικά την μοντελοποίηση του κυκλώματος στο Simulink και στην συνέχεια την χρήση των κατάλληλων εργαλείων, οπότε μέσω μιας αυτόματης διαδικασίας παράγεται ο επιθυμητός κώδικας. Η διπλωματική εργασία διαρθρώνεται με τον εξής τρόπο: Στο κεφάλαιο 1 γίνεται μια σύντομη αναφορά στον σημαντικό ρόλο που καλούνται να διαδραματίσουν οι ανανεώσιμες πηγές ενέργειας, στις σημερινές και μελλοντικές ανάγκες του τομέα της ηλεκτρικής ενέργειας. Ακολουθεί μια συνοπτική παρουσίαση της φωτοβολταϊκής τεχνολογίας και του τρόπου αξιοποίησής της. Στο κεφάλαιο 2 γίνεται η πλήρης ανάπτυξη της μεθόδου ημιτονοειδούς διαμόρφωσης εύρους παλμών για την αξιοποίησή της σε μετατροπέα DC/AC (αντιστροφέα), ενός σκέλους και τριφασικού. Παρουσιάζονται αναλυτικά τα χαρακτηριστικά της μεθόδου και ο τρόπος εφαρμογής της σε ψηφιακά συστήματα. Στο κεφάλαιο 3 γίνεται η περιγραφή και ανάλυση της πειραματικής μας διάταξης. Διαχωρίζοντας το συνολικό σύστημα στα επιμέρους κυκλώματα ισχύος και ελέγχου, περιγράφουμε την κάθε διάταξη ξεχωριστά, αναλύοντας το αντίστοιχο θεωρητικό υπόβαθρο. Ιδιαίτερα, όσον αφορά το κύκλωμα ελέγχου, αναπτύσσουμε συνοπτικά την θεωρία του PI ελέγχου, στον βαθμό που κρίνεται απαραίτητο για την εφαρμογή μας. Στο κεφάλαιο 4 παρουσιάζεται το σύστημα eZdspTM F28335. Το σύστημα αυτό περιλαμβάνει τον επεξεργαστή ψηφιακού σήματος F28335, με την βοήθεια του οποίου υλοποιούμε το κύκλωμα ελέγχου. Γίνεται αναφορά στις δυνατότητες του συστήματος και περιγράφονται τα περιφερειακά του που χρησιμοποιούνται στην παρούσα εφαρμογή. Στο κεφάλαιο 5 γίνεται η ανάλυση του μοντέλου Simulink που υλοποιεί το κύκλωμα ελέγχου. Αρχικά, παρουσιάζεται συνοπτικά η διαδικασία ταχείας προτυποποίησης και ο τρόπος με τον οποίο επιτυγχάνουμε την αυτόματη παραγωγή κώδικα μέσω των μοντέλων του Simulink. Στη συνέχεια περιγράφουμε αναλυτικά τα μπλόκ που συνιστούν το μοντέλο της εφαρμογής μας. Στο κεφάλαιο 6 γίνεται η παρουσίαση των πειραματικών αποτελεσμάτων που προέκυψαν κατά την διάρκεια των μετρήσεων. Συγκεκριμένα παρατίθενται μετρήσεις και γραφήματα που έχουν στόχο να αναδείξουν την λειτουργία του ελέγχου και τον τρόπο με τον οποίο επιδρά στο σύστημά μας. Στο κεφάλαιο 7 παρουσιάζονται τα τελικά συμπεράσματα και οι πιθανές μελλοντικές προοπτικές της εφαρμογής.
The objective of this thesis is the power supply of a variable RL load, by the use of a photovoltaic generator as our energy source, aiming to a load voltage with constant rms value and frequency. To achieve this objective, involves the use of several devices, in order to create an experimental system on which we will develop our application. Thus, our total system, other than the source (photovoltaic generator) and the load, is composed of a three-phase voltage source inverter (VSI), a three-phase transformer, a low pass LC filter, a device that electronically chooses the value of the load and a microprocessor which implements the necessary control system. The first part of the control system refers to the generation of the signals that control the switching elements of the three-phase voltage source inverter. With the help of the microprocessor we achieve the implementation of the appropriate pulse generator circuit using a method called sinusoidal pulse width modulation (SPWM). In the second part of the control system we implement a PI controller which, in collaboration with the above circuit, ensures the stabilization of the voltage on the load, therefore the uninterrupted power supply. Making step load changes, we record the variation of those parameters that confirm the operation and efficiency of the entire control system. Of great importance is the way we produce the code that implements the control circuit, when executed by the microprocessor. The procedure begins with the modeling of the circuit in Simulink, followed by the use of the appropriate development tools that result in an automatic process of production of the desired code. The thesis is organized in the following way: In Chapter 1 we give a brief reference to the importance of the renewable energy sources, regarding the present and future needs of the electricity sector. We continue with a summary of the photovoltaic technology and it’s means of exploitation. In Chapter 2 we make a thorough description of the method called sinusoidal pulse width modulation and we discuss it’s use for the DC/AC converter (inverter), both single-leg and three-phase. We give a full presentation on the characteristics of the method and the manner to be implemented in digital systems. In Chapter 3 we make the description and analysis of our experimental system. By separating the overall system to two individual parts, the power circuit and the control circuit, we describe each device separately and analyze the relevant theory. In particular, with respect to the control circuit, we summarize the theory of PI controller, to the necessary extent for our application. In Chapter 4 we introduce the system eZdspTM F28335. This system includes the digital signal processor F28335, which undertakes the implementation of the control circuit. Reference is made to the overall capabilities of the system and especially to the peripherals used in this application. In Chapter 5 we give the analysis of the Simulink model which implements the control circuit. Initially, we outline the procedure of rapid prototyping and describe the way in which we achieve the automatic production of our executable code through the Simulink models. Then we describe in detail the blocks that form the model of our application. In Chapter 6 we present the results obtained during the experimental phase. In particular there are listed measurements and graphs that aim to highlight the function of the control system and the manner in which it influences our system. In Chapter 7 we present our final conclusions and possible future prospects of the application.

This chapter presents a three-cell flying capacitor converter photovoltaic (PV) system. This system consists of a DC-DC boost power converter connected in series with a multicell inverter. The perturb and observe MPPT technique has been used to extract the maximum power from the solar panel and generate the duty signal to control the switch of the DC-DC converter. The three-cell flying capacitor inverter ensures the conversion of the output voltage of the boost chopper to the alternative voltage. This topology is made up of hybrid association of commutation cells, which makes it possible to share the voltage constraint on several switches. A closed loop control based on PWM has been proposed to control the capacitor voltages of the inverter. The output current is controlled using a PI regulator. The aim of the proposed three cell inverter is to produce an approximate sinusoidal output current with a very low THD. The simulation results assess the effectiveness of the control.