Search results for "Filter"
showing 10 items of 1019 documents
Design of a configurable multispectral imaging system based on an AOTF.
2011
In this paper, we present a configurable multispectral imaging system based on an acousto-optic tunable filter (AOTF). Typically, AOTFs are used to filter a single wavelength at a time, but thanks to the use of a versatile sweeping frequency generator implemented with a direct digital synthesizer, the imager may capture a configurable spectral range. Experimental results show a good spectral and imaging response of the system for spectral bandwidth up to a 50 nm.
Electronic noses: a review of signal processing techniques
1999
The field of electronic noses, electronic instruments capable of mimicking the human olfactory system, has developed rapidly in the past ten years. There are now at least 25 research groups working in this area and more than ten companies have developed commercial instruments, which are mainly employed in the food and cosmetics industries. Most of the work published to date, and commercial applications, relate to the use of well established static pattern analysis techniques, such as principal components analysis, discriminant function analysis, cluster analysis and multilayer perceptron based neural networks. The authors first review static techniques that have been applied to the steady-s…
PMSM Drives Sensorless Position Control with Signal Injection and Neural Filtering
2009
Vector Field Oriented Control (FOC) is one of the best control methods for high-dynamic electrical drives. To avoid the adoption of the speed/position sensor (resolver/encoder), a sensorless technique should be used. Among the various sensorless methods in literature, those based on machine saliency detection by signal injection seem to be most useful for thier giving the possibility of closing the position control loop. This paper proposes a method for enhancing both rotating and pulsating voltage carrier injection methods by a neural adaptive band filter. Results show the goodness of the proposed solution.
New distributed model for synthesis of classical dual mode filters
2010
Up to now, distributed models for classical dual mode filters have not been developed. In this paper, the whole procedure to derive such distributed models is shown step by step. The resulting formulas are very similar to those standard ones used for in-line filters since the 1960s. Model limitations, very similar to those related to classical formulas, in terms of precision and bandwidth, are pointed out. Finally, two practical examples of distributed models of dual mode filters for satellite transponders with different orders have been extracted.
Hybrid Procedure for Automated Detection of Cracking with 3D Pavement Data
2016
Pavement cracks are considered a major indicator of pavement performance. Because traditional manual crack surveys are dangerous, time consuming, and expensive, technologies have been developed to collect high-speed pavement images, and numerous algorithms have been proposed to detect cracks on pavement surface. The latest PaveVision3D Ultra system (3D Ultra) has been implemented to achieve 30-kHz three-dimensional (3D) scanning rate for 1-mm resolution pavement surface data at highway speed up to 100 km/h (60 mi/h). This paper presents the application of a hybrid procedure for automated crack detection on 3D pavement data collected using 3D Ultra. The procedure combines three different me…
Optimized design of high power density EMI filters for power electronic converters
2016
Nowadays, power density of power converters and related EMI filters is gaining more and more attention. This severely impacts on the design constraints in several application domains. A conventional design of the EMI filter does not guarantee the selection of components/configuration leading to the best power density. For this reason, an optimized design procedure of discrete EMI filters in terms of power density is proposed in this paper. It is based on a previously developed rule-based design procedure, introducing here additional features to obtain a more effective optimization of EMI filter's power density. The proposed approach has been validated in terms of EMI filter's performance an…
Fuzzy Adaptive EKF Motion Control for Nonholonomic and Underactuated Cars with Parametric and non Parametric Uncertainties
2007
A new fuzzy adaptive motion control system including on-line extended Kalman''s filter (EKF) for wheeled underactuated cars with non-holonomic constraints on the motion is presented. The presence of parametric uncertainties in the kinematics and in the dynamics is treated using suitable differential adaptation laws. We merge adaptive control with fuzzy inference system. By using fuzzy system, the parameters of the kinematical controller are functions of the lateral, longitudinal and orientation errors of the motion. In this way we have a robust control system where the dynamics of the motion errors is with lower time response than the adaptive control without fuzzy. Also Lyapunov''s stabili…
A New Generalized Robust Predictive Current Control for Grid-Connected Inverters Compensates Anti-Aliasing Filters Delay
2016
In this paper, a new predictive control for grid-connected inverters is presented, which provides the best performance in terms of transient response and stability margins when analog filters in current sensing circuits are used. These filters are necessary to avoid aliasing in the A/D conversion process, which causes an important ripple on injected current into the grid and increases the total harmonic distortion. However, predictive controls are very sensitive to delays on the acquisitions, so when such anti-aliasing filters are used a reduction of stability margins is produced and the transient response is affected. The proposed predictive control allows to compensate the effect of the f…
Fast automated design of waveguide filters using aggressive space mapping with a new segmentation strategy and a hybrid optimization algorithm
2005
Waveguide filters are key elements present in many microwave and millimeter-wave communication systems. In recent times, ever-increasing efforts are being devoted to the development of automated computer-aided design (CAD) tools of such devices. In this paper, a novel CAD tool based on modal analysis methods, which improves the efficiency and robustness of the classical aggressive space-mapping technique, is presented for those purposes. The use of a new segmentation strategy and the hybridization of a specific combination of several well-known optimization algorithms is proposed. The CAD tool has been successfully validated with the practical design of several H-plane coupled cavity filter…
Waveguide filters for satellites
2007
This article describes the historical evolution, and its theoretical and technological features of waveguide filters. All-metal waveguide filters have been widely used in satellite payloads since the advent of the first space communication systems four decades ago. In this period, such technology has been continuously evolving due to the increasing requirements demanded to these components. Special attention has also been paid to present the most recent advances in the development of CAD tools for satellite filters, which are based on full-wave electromagnetic analysis methods. Finally, the compact solutions for the input and output stages of satellite payloads are focused on, thus consider…