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This paper deals with the reliability assessment for an UAV (Unmanned Aerial Vehicle) system: once a specific architecture is selected (after a trade-off phase), the reliability assessment represents a key issue to optimize the design of any complex system. The final aim is to evaluate the intrinsic reliability at the design stage to avoid any critical failure that may leads to a catastrophic effect on the UAV.

A sensor network for aerospace applications is presented. The single node has been designed to follow important requirements in aerospace environments such as low power consumption, lightweight and reliability. Moreover, the network does not use radiofrequency transmitter/receiver to send the information, using infrared technology instead. The network has been designed, realized and tested. Some sample measurements are shown.

In order to develop an Automatic Pesticide Detection System an electronic nose based on an array of commercial gas sensors has been realized. The sensors works in parallel and a qualitative response to different pesticides has been found through the use of a self-made measurement bench.

A modified version of LEACH routing protocol has been implemented and simulated in Castalia simulator to verify if it was good to manage a WSN dedicated for necropolis. Simulation results seem to show the valence of our idea.

A non-recursive version of Nonlinear Least Squares Fitting for frequency estimation is presented. This problem yields a closed-form solution exploiting a Taylor’s series expansion. Respecting some conditions, the computational complexity is reduced, but equally the method assures that the accuracy reaches the Cramer-Rao Bound. The proposed method requires a frequency pre-estimate. A series of simulations has been made to determine how accurate the pre-estimate should be in order to ensure the achievement of the Cramer-Rao Bound in various conditions for different periodic signals. The execution time of the proposed algorithm is smaller compared to a single iteration cycle of the standard approach. The proposed method is useful in applications that require a high accuracy fitting of periodic signals, especially when limited computational resources are available or a real-time evaluation is needed.

In this paper, we propose a new sensor for the detection and analysis of dusts (seen as powders and fibers) in indoor environments, especially designed for applications in the field of Cultural Heritage or in other contexts where the presence of dust requires special care (surgery, clean rooms, etc.). The presented system relies on image processing techniques (enhancement, noise reduction, segmentation, metrics analysis) and it allows obtaining both qualitative and quantitative information on the accumulation of dust. This information aims to identify the geometric and topological features of the elements of the deposit. The curators can use this information in order to design suitable prevention and maintenance actions for objects and environments. The sensor consists of simple and relatively cheap tools, based on a high-resolution image acquisition system, a preprocessing software to improve the captured image and an analysis algorithm for the feature extraction and the classification of the elements of the dust deposit. We carried out some tests in order to validate the system operation. These tests were performed within the Sistine Chapel in the Vatican Museums, showing the good performance of the proposed sensor in terms of execution time and classification accuracy.

A new acquisition system for remote control of wall paintings has been realized and tested in the field. The system measures temperature and atmospheric pressure in an archeological site where a fresco has been put under control. The measuring chain has been designed to be used in unfavorable environments where neither electric power nor telecommunication infrastructures are available. The environmental parameters obtained from the local monitoring are then transferred remotely allowing an easier management by experts in the field of conservation of cultural heritage. The local acquisition system uses an electronic card based on microcontrollers and sends the data to a central unit realized with a Raspberry-Pi. The latter manages a high quality camera to pick up pictures of the fresco. Finally, to realize the remote control at a site not reached by internet signals, a WiMAX connection based on different communication technologies such as WiMAX, Ethernet, GPRS and Satellite, has been set up.

The proposed remote-control system can optimize management and efficiency of street lighting systems. It uses ZigBee-based wireless devices which enable more efficient street lamp-system management, thanks to an advanced interface and control architecture. It uses a sensor combination to control and guarantee the desired system parameters; the information is transferred point by point using ZigBee transmitters and receivers and is sent to a control terminal used to check the state of the street lamps and to take appropriate measures in case of failure.

This article describes a new instrument for power quality (PQ) measurements based on the Raspberry-Pi. This is the latest step of a long study started by the Electric and Electronic Measurements Laboratory of “Roma Tre” University 12 years ago. During this time, the Laboratory developed and refined instrumentation for high accuracy power quality measurements. Through its own architecture, the new instrument allows the use of the Raspberry instead of a personal computer (PC). The data acquired and locally processed are then sent to a remote server where they can be shown to users. Imagines of the system and of the data prove the activity of the system.

After a description of soilless cultivations and the presentation of a control system to manage all phases of a greenhouse designed and built for Earth's applications, the article shows a procedure to get the space certification for this kind of system.

A new inexpensive data logger specific designed to monitor the behavior of small animals in extreme scenario will be presented. The new data logger is based on common, commercial affordable and reliable devices that assure inexpensiveness and, at the same time, could be the base for further reasonings and developments with the aim to improve the device to face stressing scenarios such as that aerospace. Preliminary test realized in laboratory and in field have demonstrated its reliability.

In the Life Cycle Management context of complex systems there are a few 'families' of products which, due to the aleatory behavior of the development and production processes, present difficulties in the management of the remaining usable life and spare parts approach. One of such 'family' is represented by composite materials and products. This article proposes a methodology to improve their support through the mapping of the zonal/functional characteristics of each item on a LSA Database (ASD S3000L will be used as the example).

The hystory of how an Italian Little Enterprise designed and certified a special product as a sensor and its electronic control system for spacecraft vehicle will be shown. The way to reach the final objective will be related describing the single steps followed.

Following a business as usual scenario, some Low Earth Orbit (LEO) regions could be unusable for many decades because of the space debris growth. In order to reduce that trend, the current probability of success of the chosen End of Mission (EOM) disposal method shall ensure a target value of 90% [1]. Understanding reliability of satellites and their subsystems for different spacecraft classes allows determining which disposal solution could better fit with a particular space mission. However, spacecraft are quite often different from each other, so a statistical approach is required. An in depth study has been performed on 1086 spacecraft launched between January 2000 and December 2014 using data from the SpaceTrak™ database. Spacecrafts have been separated by mass and by the presence/absence of the propulsion subsystem. The non-parametric Kaplan-Meier survival analysis has been used because the dataset presented censored events, namely the observed variable value is partially known. Empirical reliabilities obtained have been fitted using the Weibull distribution. Because each disposal method needs a combination of subsystems in order to operate, the reliabilities of the different subsystems have been combined by means of the System Reliability Theory. General spacecraft reliability was found to be about 92% after 4 years. The presence of the propulsion subsystem results in a better reliability trend. Furthermore, the propulsion presence/absence classification being equal, the heavier the mass the worse the reliability. Disposal solutions that use communication and power subsystems can count on reliabilities above 90% up to 7 years, whereas those ones that need also the attitude control can rely on only an 85% reliability after 4 years. A trade-off was performed and it showed that the film aerobrake and the propulsive D-Orbit decommissioning device can be key resources as disposal methods for future missions. The results presented could be useful to the space industry, to better address its efforts in improving spacecraft reliability and to design more reliable EOM disposal methods in order to reduce space debris growth.

Traditionally, prognostics has been performed by continuous monitoring of quantities that are empirically assumed to sum up the evolution of the observed phenomenon. Only recently, physics-based model simulations have been considered as a valid help to understand the evolution of the chemical-physical processes leading to failure. Nevertheless, physics-based models have always been paired with data driven models and that has led to the development of heavy hybrid approaches. It is opinion of the authors that in a wide range of situations, with the current knowledge of physics, it is possible to model processes and their evolution based only on the physics model simulations, using what's called “propagation of uncertainty technique” on every aspect, from components to system behavior. The authors developed such a technique valid for both Time-Independent and Time-Dependent phenomena. This approach allows probabilistic simulations to be carried out. The proposed methodology simultaneously uses the rated values of the involved parameter in the considered process and their uncertainties as inputs. As outputs it provides the expected values of the process with their standard deviations (std) and their probability distributions. The authors developed also the software tool RELYSOFT which allows to directly supply rated values and their uncertainties as inputs. The simulations can be performed by means of analytical equations in definite form, differential equations or by Finite Element approach. The Finite Element simulation will be the subject of a later work. In case of simulations by means of analytical equations in definite and differential form, a new pseudo algebra has been developed in order to perform assessments. Two examples are reported concerning aero-spatial field: a Time-Independent and a Time-Dependent.

Recent developments in the Logistic Engineering field are expanding the range of analysis for Operational Availability (Ao) from purely statistical models to include prognostic models. A necessary step in order to perform prognostic analysis is the study of system's components degradations. The degradation of a component is a case by case study, which characteristics that change significantly even inside the same component macro area (software, composites, mechanical parts etc.). The degradation models project over time the key factors of each component, eventually ending with the component failure (exceptions can be made for software). For those models the initial degradation state is an heavily influencing factor. Assuming that a component starts it's degradation process from a pristine state, relative to the value for which it is tested and conformed, introduces an error in the Remaining Useful Life assessment. Components used in systems have varying degrees of degradation at the t 0 of the system, which may be greater or lesser than the assumed value. This happens cause conformity tests do have tolerances in the accepted values. Using the effective measurements derived from the conformity tests can improve the accuracy of the Remaining Useful Life (RUL) evaluation.

Dust deposition and pollution are relevant issues in indoor environments, especially concerning human health and conservation of things and works. In this framework, several tools have been proposed in the last years in order to analyze dust deposition and extract useful information for addressing the phenomenon. In this paper, a novel approach for dust analysis and classification is proposed, employing machine learning and fuzzy logic to set up a simple and actual tool. The proposed approach is tested and compared with other already introduced similar techniques, in order to evaluate its performance.

The aim of this work is to propose a metrological system for the definition of the Extra Virgin Olive Oil Quality based on Panel Test. The information was obtained by a Kohonen neural network that simulates the biological perception mechanisms. This approach allowed to get a two-dimensional mapping of the flavors based on non-linear model. The predominant flavors are not evenly distribute on the map but they are located in specific zone. It is also possible to identify a separation between negative and positive attributes that defines a “quality direction” from low grade to high quality Extra Virgin Olive Oils. Moreover, the overlaps of different flavors on the same neuron of the map suggest possible correlations between them. This is an important starting point to identify the minimum number of independent attributes in order to optimize the Panel Test questionnaire.

The paper shows the strategies of choice of recovery methods of the RAM when, in space environment, they are affected by various SEE phenomena. The article considers various recovery methodologies, including two scrubbing methods (deterministic and probabilistic) and the criteria of choice according to the kind of mission in which the component is involved.

In this work, the authors study the possibility to use the simulated prognostic with the aim to minimize the maintenance costs. The authors propose the introduction of the uncertainties in the input parameters including those of the degradation material laws obtaining precise and accurate predictions of the process evolution. The use of this procedure has the great advantage of the minimization of the maintenance costs compulsorily linked to the prognostic applied to the maintained system. Two applications are also described.

Through the concept of the “physics of failure,” this article analyzes a possible extension of the modern Logistic Support Analysis (LSA) databases such as ASD S3000L in order to support a new view of operational availability based on the categorization of stresses obtained by operational scenarios and applicable to FMMEA (Failure Mode Mechanism Effect Analysis). In order to integrate such methodologies inside the actual ILS (Integrated Logistic Support) process, new database parameters and stress/failure physics categorization classes needs to be defined. This article discusses this problematic and proposes some extensions of the ASD S3000L LSA data model.

A distributed web-based system for temporal and spatial power quality analysis has been realized and tested. Connecting by internet local instruments able to perform high accuracy measurements in real time, the Power Quality information, locally measured, can be sent to a remote central server which aim is to plot them and stored the data for future analysis. The remote instruments have been realized, tested and placed in two Italian cities, Palermo and Rome, where actually work while the server works in Rome. The web application allows to select the single instrument and to show its stored PQ information.

After a brief description of Non Destructive Technique (NDT) used for the durability check and test of aerospace material, a comparison between traditional methods and new techniques based on Thermography and Shearography is made. A case study is also presented and discussed.

In this work we present an investigation on a conductive thermoplastic nanocomposite used as flexible and stretchable strain gauge to be applied on inflatable structures for both terrestrial and extra-terrestrial applications. In particular we analysed the sensor behaviour by using an one-dimensional expansion system for increasing strain up to 5% and we studied the device changing in temperature. The strain gauge was also tested after several expansion cycles thus analysing the sensor response in time and ageing effects. Finally we tested the sensor on an inflatable naval fender in order to reproduce the sensor behaviour in real conditions.

In this work we will illustrate the criteria useful to identify simple and quick operations through which “the why and the when” a scheduled maintenance can be performed in order to avoid excessive checks and controls, often difficult and expensive to run. The question that in fact arises in the preparation of preventive maintenance program is if it is possible to satisfy the reliability requirements compatible with the economic and safety needs of the user. The answers can only be given following a correct heuristic method. Experimental data, resulting from repetitive measurements, should only serve to build simulation models that can predict what the future will hold and then as subsequent control measurements to confirm the above-mentioned model. This is particularly useful in the planned maintenance schedule, in which you get to answer the question: "how often"? Fit mathematical models allow to calculate, with precision and accuracy, the convenient time at which to intervene. To do this, it is therefore necessary to understand the mechanisms that dominate the evolution of the processes (prognostics) that may lead to failures. We present two examples of applications: one concerning a railway structure and the other relative to an aircraft structure.

In this paper, an innovative and automated fault detection and diagnosis (FDD) approach based on high-level correlation rules in order to improve reliability, safety and efficiency of a supervised building is presented. The proposed method is based on the data fusion of different measurements, using their fuzzification and aggregation through suitable operators, in order to get dimensionless severity indicators able to diagnose faults and to identify the possible causes (ranked according their severity) generating them. Thus, a set of possible anomalies that can occur in a building and the correlation with measured physical quantities were identified. Experimentation of this FDD technique was applied to indoor lighting of a real office building. The proposed method was validated over a onemonth period with the aim of detecting anomalous consumption events, considering when and in which circumstances they occurred. After this stage, the FDD system was performed in real time operation. Keywords: fault detection and diagnosis, smart building, BEMS, data fusion approach, fuzzy logic, sustainability.

The advent of new sensors allows to create smaller and lighter inertial systems than ever before: thanks to their compact size, low cost and low power consumption, they can be installed on flying platforms such as UAV systems, to improve the reliability of autonomous navigation. The merging of the Inertial Reference System (IRS) and GNSS data through the Kalman filter gives a significantly improve to the autonomous navigation performance both in terms of accuracy and integrity. This paper is focused on the methods and techniques of GNSS integrated with an Inertial Reference System and their applications in UAV autonomous navigation systems.

Nowadays, the check of the organoleptic characteristics for the evaluation of extra virgin olive oil (EVOO) quality is regulated by the European Union (EU) authorities, which indicate the use of the panel test (PT). It is composed by a team of specialists that give a numerical value to many characteristics about flavours, synthesising a sensory analysis. Each expert answers questions about the aroma by assigning the adequate scores to each oil. The evaluation becomes objective by applying the statistical analysis of all the scores given by the participants: This is the definition of “measure” of Russell. The PT can be considered a true standard “metrological system” (considering the number of questions in the questionnaire), while the perceptions of the testers are the solicitations of it. To allow access to an expensive evaluation process by small companies, this work proposes to “disseminate” the properties of the metrology represented by PT. The results of the PT are arranged in an unsupervised artificial neural network (ANN), the Kohonen map, which represents the synthesis of self-organised output that has only the goal, in this paper, to make readable PT results. The dissemination process is obtained by the gas chromatographic (GC) analysis of each oil sample and through the identification of peaks corresponding to the perceptions. These signals are used for the training of the supervised Multi Layer Perceptron (MLP) ANN, with the back propagation algorithm, whose outputs are represented by the results of the PT. This procedure is exact a “metrological dissemination of a standard” and also the aim of the work: to classify EVOO without always resorting to PT.

""The problem of the electrical energy price, evaluated considering its quality, has been analyzed in this article. The electrical energy quality is directly defined by the customers as an output of a complex procedure which uses as inputs both the power quality technical parameters and the human experience. The procedure shows as the accuracy in the quality definition is strongly related with the accuracy of the sensors used for the power quality measurements, especially regarding their synchronization. An analysis of the synchronization of the sensors placed on a spread territory is also made. A solution for a centralized control of the sensors time course is also suggested."" It has been taken into account the problem of the price of the electrical energy considering its quality. This last is defined by the customers after a complex procedures which considers as inputs both the technical parameters and the human experience. In Following this procedure the final accuracy in the quality definition is strongly related with the accuracy of the sensors used for the power quality measurements especially regarding their synchronization which becomes particularly problematic considering their distribution on spread territory. Moreover we suggest the solutions for a centralized control of their time course.

Starting from gas-chromatograms of extra virgin olive oil samples, choosing the most significant peaks, authors try to define a standard ortho-normal base to be deposited for quality valuation.

An alternative process for the evaluation of the economic risk bound to the insurance of an aircraft is presented. Such process is built from two potentially complementary methodologies, used for risk and fault analyses (ERC and FMECA), combined with a cooperative agreement between flight and insurance companies, that meets the recent tendencies on aviation Safety Management Systems. This innovative procedure should allow the periodic update of the economic risk bound to the insurance while lowering the general costs for risk evaluation thus resulting in a lower insurance premium and increased competitiveness.

An electronic sensor card for aerospace applications is presented. The device uses infrared technology to transmit measurements toward a central unit. It has been designed following a low power consumption strategy which allows the use of a mini photovoltaic panel supplier. The card could be efficiently used in structures which ensure the line of sight between the card and a central receiver unit as inflatable structures. The device has been realized and tested.

Surface roughness evaluation is very important to characterize surface finish. Roughness parameter can be calculated in either two-dimensional (2D) or three-dimensional (3D) form. 2D profile analysis has been widely used in science and engineering for more than half century. In recent years, there was an increases need for 3D surface analysis. The aim of this paper is to present a new optoelectronic system based on two lasers diode for 3D real-time surface roughness measurement. 3D surface roughness parameter ( S q ), of a surface characterized by a stationary Gaussian random process, is estimated using Spectral Speckle Correlation (SSC). In the paper, theory is described and experimental results are given.

An important problem in industrial system, both working in low and medium power, is the possibility that some circuits have a current dispersion, with a subsequent increasing in local temperature. This situation, if not immediately corrected, can produce, in some cases, firing accidents, with a great amount of money loss and long period of out-of-order systems. Although procedures based on Infrared Thermography to analyze and find critical situations already exist, these are always based on long manual procedures and usually are used for analysis of complex industrial systems. In this paper, after a short review of the common manual thermograph investigation, an automatic system based on two infrared thermograph cameras and an image processing real time analysis is proposed. The device demonstrates the possibility to take under control some critical systems and preventing firing accident in automatic way. This solution can be easily integrated in a SCADA architecture for monitoring and alerting the supervisor about over-temperature or current dissipation cases.

The artwork market is plenty of unauthorized reproduction of original products. One of the most varies filed is the counterfeiting of Authenticity Certificate related to paints, lithography, sculptures, etc., with the aim to create an illegal market of reproduced copies. To resolve this problematic, it is possible change the current paper certificate, related to a single artwork, with a digital version, which will contain some specific information, related to the artwork itself. In this paper, starting with the well-known advantages given by the biometry paradigm in human authentication, we propose a method able to distinguish the single “non-living” objects. In other words, we propose an approach that, by using the random inimitably characteristics, is able to uniquely identify artworks such as painting, lithographs, sculptures, etc. In this way it could be possible creating a secure digital certificate of authenticity (digital COA). Due to the high density information available in modern acquisition media, it is possible using a Speckle Metrology approach. During verification phase, the same area has to be acquired, to extract embedded verification data. It is possible to secure this data using a private key, necessary for accepting the digital signature. The presence of possible geometrical distortions between image present in the certificate and acquired during the verification phase, it is necessary applying geometrical corrections based on affine transformation, before executing the correlation methodologies, used in speckle metrology.

A deep analysis of the Fuel Cells technologies state of the art has been done in this article. After a general de- scription of the fuel cell base structure the six most important fuel cell technologies Polymeric Electrolyte Membrane Fuel Cells (PEMFC), Direct Methanol Fuel Cells (DMFC), Alkaline Fuel Cells (AFC), Phosphoric Acid Fuel Cell (PAFC), Molten Carbonate Fuel Cell (MCFC), Solid Oxide Fuel Cell (SOFC) are explained, describing advantages and disadvan- tages of each one and pointing out their principal use. The future development are also shown.

Source: doi: 10.3390/electronics5030058 A new device based on the Raspberry-Pi to monitor the locomotion of Arctic marine invertebrates and to analyze chronobiologic data has been made, tested and deployed. The device uses infrared sensors to monitor and record the locomotor activity of the animals, which is later analyzed. The software package consists of two separate scripts: the first designed to manage the acquisition and the evolution of the experiment, the second designed to generate actograms and perform various analyses to detect periodicity in the data (e.g., Fourier power spectra, chi-squared periodograms, and Lomb–Scargle periodograms). The data acquisition hardware and the software has been previously tested during an Arctic mission with an arctic marine invertebrate

After a description of Electrochemical Impedance Spectroscopy methods, a new instrument extremely cheaper than market ones and suitable for fuel cells investigation will be presented. The characteristics for the system will be calculated and presented also together with some measurements realized.

We propose an innovative wireless street lighting system with optimized management and efficiency. Wireless communication uses ZigBee-based wireless devices which allow more efficient street lamp system management, thanks to an advanced interface and control architecture. It uses many sensors to control and guarantee the optimal system parameters; the information is transferred point-by-point using ZigBee transmitters and receivers and is sent to a control terminal used to check the state of the street lamps and to take appropriate measures in case of failure. The system allows substantial energy savings with increased performance and maintainability.

After an introduction to PLL and PLL based systems, an analysis of the methods to improve the performance of such systems aimed to the Harmonic Analysis is presented. Among these methods an approach to using the Genetic Algorithm is shown with its results.

An energy saving system able to optimize power management and energy efficiency of an home heating plant is proposed. Thanks to an advanced interface and control architecture based on ZigBee wireless devices, a continuous control of temperature is warranted making efficient the heating plant. The system uses a sensor and actuator combination to control and guarantee the desired system parameters; the information is transferred point-by-point using ZigBee communication network and it's sent to a central unit used to check the peripheral devices state and to take appropriate measures in case of failure or alarm.

An overview of the IEEE Standard 2030, IEEE Guide for Smart Grid Interoperability of Energy Technology and Information Technology Operation with the Electric Power System (EPS), End-Use Applications, and Loads, is presented. The article well explains as the interoperability is the first step versus a complete integration of Smart Grids.

This paper proposes a simple method for the analysis of the resonance frequency of a planar spiral coil used for wireless energy transfer via magnetic resonant coupling (Witricity), and illustrates an algorithm that was designed, through an advanced programming and computing software, to evaluate the lumped parameters of the coils.

Starting from a previous work, a new Data Acquisition USB Device has been designed, developed, realized and characterized to be used in Power Quality and Smart Grid applications. The system simultaneously manages 8 data acquisition channels to allow voltages and currents monitoring on tri-phases lines. It can get external both certified time and voltage references to warranty certified measurements, but it also use internal references for non certified ones. The USB card is in PCI form factor and can be placed inside a common PC slot or in external shielded housing. FTDI Virtual ComPort drivers yield to a flexible multiplatform device, without requiring any advanced programming skill. The proposed device has been tested with custom software written in C# and VB6 languages, moreover it has been characterized applying the most common ADC performing test to verify its behavior.

The increasing growth of electricity usage in buildings points out the significant role of residential users in the programs for the efficient control and management of electrical energy. The shaving of consumption peaks in household is becoming an integral part of the national energy strategies to reduce the risk of blackouts and ensure environmental sustainability of new urban context. This paper investigates the use of the paradigm of swarm intelligence to scheduling the operation of household appliances in order to reduce to smooth the variation and reduce the peak-to-average ratio of total electricity demand at home. Simulation results confirm the proposed approach.

This paper proposes an FPGA based device. implementing a signal generator for power quality analysis. The device simulates the behavior of an ADC connected to the power grid. It’s main goal is to make it easy to have real-time tests on algorithms implemented on embedded hardware.

After the description of FMECA methodology applied to vulnerability evaluations typically in electronic context, an its use is suggested for powerline in case of earthquakes. The procedure gives a series of quantification risk tables which correctly filled give the indication of the probability risk for each harm of the electric network becoming an useful instrument to preventively fix where primarily act in case of a disaster.

After a brief description of Folding ADCs, also compared with Two-Steps ADCs, the principle function of an interpolative structures for these converters has been analyzed. It has been underlying as this structure improves the performances of the whole ADC. Some considerations allow to quantify the best design choices. A simulation of the converter has been also realized by PSPICE.

An instrument based on FPGA to determine in few. periods the fundamental frequency of a electrical grid signal has. been realized. A classic algorithm as Curve Fitting Algorithm has. been analyzed and modified to reduce its numerical complexity.. This paper shows how the floating point software algorithm has. been implemented on hardware architecture in fixed point. representation, controlling the accuracy.

PLL principles system and its applications in. harmonic analysis are firstly discussed and then integrated. presenting methods to increase the PLL-based instrumentation. efficiency. A comparison between the performance of systems. before and after the application of these methods are shown to. validate the efficiency o f the proposed methods.