Academic literature on the topic 'Filters'
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Journal articles on the topic "Filters"
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Kaufman, Amanda R., Lisa M. Casanova, and Mark D. Sobsey. "Efficacy of a ceramic siphon household water filter for removal of pathogenic microorganisms: lifespan volume test." Journal of Water, Sanitation and Hygiene for Development 1, no. 2 (June 1, 2011): 102–11. http://dx.doi.org/10.2166/washdev.2011.037.
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Treatment of drinking water at the point of use (POU) has demonstrated health benefits for people who have access only to microbially contaminated drinking water. In this work, the ceramic siphon POU water filter was evaluated for its ability to reduce indicator microorganisms in test waters. During batch challenge tests, the filter reduced Escherichia coli in filtered water by 7 log10 (99.999987%) and bacteriophage MS2 by 0.12 log10 (24.0%). Next, a novel continuous flow dosing system allowing sewage-amended feed water to constantly pass through the filters allowed for determination of changes in microbial reductions over time and total volume of water filtered. E. coli B, MS2 and fluorescent microspheres (as a surrogate for Cryptosporidium oocysts) were seeded into test water and dosed to filters at 10, 25 and 50% of the filter's volume lifespan. Microbial removal efficacy decreased as the volume of water filtered increased and test filters did not achieve their volume lifespan before physically failing. The ceramic siphon household water filter is effective in reducing E. coli and surrogates for Cryptosporidium in water, but filter modifications may be needed to achieve acceptable levels of virus removal and to reach the target 7,000 L volume lifespan of the filter.
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Trantham, E. Clark. "Minimum uncertainty filters for pulses." GEOPHYSICS 58, no. 6 (June 1993): 853–62. http://dx.doi.org/10.1190/1.1443469.
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The objective of this paper is to calculate filters with a minimum uncertainty, the product of filter length and bandwidth. The method is applicable to producing minimum uncertainty filters with time or frequency domain constraints on the filter. The calculus of variations is used to derive the conditions that minimize a filter’s uncertainty. The general solution is a linear combination of Hermite functions, where the Hermite functions are summed from low to high order until the filter’s constraints are met. Filters constrained to have zero amplitude at zero hertz have an uncertainty at least three times greater than expected from the uncertainty principle, and the minimum uncertainty filter is a first derivative Gaussian. For the previous filter, the minimum uncertainty high cut filter is a Gaussian function of frequency, but the minimum uncertainty low cut filter is a linear function of frequency.
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Ahmed, Osman, Shermeen Sheikh, Patrick Tran, Brian Funaki, Alexandria M. Shadid, Rakesh Navuluri, and Thuong Van Ha. "Inferior Vena Cava Filter Evaluation and Management for the Diagnostic Radiologist: A Comprehensive Review Including Inferior Vena Cava Filter-Related Complications and PRESERVE Trial Filters." Canadian Association of Radiologists Journal 70, no. 4 (November 2019): 367–82. http://dx.doi.org/10.1016/j.carj.2019.06.003.
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Inferior vena cava filters are commonly encountered devices on diagnostic imaging that were highlighted in a 2010 Food and Drug Administration safety advisory regarding their complications from long-term implantation. The Predicting the Safety and Effectiveness of Inferior Vena Cava Filters (PRESERVE) trial is an ongoing after-market study investigating the safety and utility of commonly utilized filters in practice today. While most of these filters are safe, prompt recognition and management of any filter-associated complication is imperative to prevent or reduce the morbidity and mortality associated with them. This review is aimed at discussing the appropriate utilization and placement of inferior vena cava filters in addition to the recognition of filter-associated complications on cross-sectional imaging. An overview of the PRESRVE trial filters is also provided to understand each filter's propensity for specific complications.
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Li, Luping, Lijuan Dong, Peng Chen, and Kai Yang. "Multi-band rejection filters based on spoof surface plasmon polaritons and folded split-ring resonators." International Journal of Microwave and Wireless Technologies 11, no. 08 (April 17, 2019): 774–81. http://dx.doi.org/10.1017/s1759078719000369.
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AbstractA dualband rejection filter and a triband rejection filter are proposed in this letter, both of which are implemented by cascading spoof surface plasmon polaritons (SSPPs) of the same structure but with diverse rejection bands. Compared with traditional ones, the proposed filters provide more compact structures, wider rejection bands, and better independent tunability. In the proposed filters, the rejection bandwidth, the center frequency of the rejection band and the filter's cutoff frequency can be adjusted independently. And the different rejection bands in the same filter also can be independently controlled. Agreements between the dispersion of SSPP units and the S21 of filters are also presented. Measurement results demonstrate that both filters load multiple rejection bands on the 27.7 GHz wide low-pass band and all the rejection bands locate in Ku and K bands. The average rejection bandwidth and the average rejection depth of the two filters are 1.49 GHz and 42.1 dB, respectively.
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Wang, Wenli, and Philip Winters. "Statistically Significant Efficiency Testing of HEPA Filters." Journal of the IEST 47, no. 1 (September 14, 2004): 101–6. http://dx.doi.org/10.17764/jiet.47.1.bq380t6134311822.
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High Efficiency Particulate Air (HEPA) filter manufacturers must ensure the accuracy of efficiency testing for these filters and, at the same time, keep productivity at a reasonable level. This study describes tests conducted to determine the minimum time required to provide statistically significant efficiencies of HEPA filters using a test system currently in use of HEPA filter production. The test results of over 300 HEPA filters were analyzed in this study. The approaches in IEST RP-CC-007.1: Testing ULPA Filters for statistical analysis of particle counts were followed. A Poisson distribution was used to describe the variations and to calculate the lower and upper limits of measured counts at 95% confidence level. This study shows that 90 seconds is sufficient for this test system to determine whether a HEPA filter has an efficiency of 99.990% or higher at 95% confidence. Longer tests will cause the mean measured efficiency to approach the filter's true efficiency and also narrow the confidence interval. However, challenging HEPA filters made of glass fiber media with oil aerosols for up to one hour does not significantly change the filter's true efficiency performance. The preferred approach for a new test system is to use software that calculates the confidence limits of filter efficiency after each sampling cycle and determines whether to continue testing. For an existing system without this type of program (such as the one evaluated in this study), analysis is necessary to make sure the HEPA filters are challenged with enough aerosol particles.
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Hruschka, Crassen, Udo Barabas, and Lutz Gohler. "Optical narrow band filter without resonance's." Facta universitatis - series: Electronics and Energetics 17, no. 2 (2004): 209–17. http://dx.doi.org/10.2298/fuee0402209h.
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This paper introduces an optical wave filter, which uses gratings at 45? or 135? inclined grating lines that avoid any resonance's. Therefore, many more options to form the filter shape exist. In general, the filter design can be traced to that of transversal filters (finite impulse response filter, FIR filter). Such an integrated optical wave filter is characterized by steep filter slopes and a narrow pass band (less then 01nm) combined with a high stop band attenuation (more than 40dB) and a linear phase response in the pass band. Compared to conventional Bragg grating filters, the inclined grating line filters can have a flatter pass band and steeper filter skirts related to the width of the pass band. In general, the filter's realization is possible using any optical material. In view of the excellent optical properties the semiconductor material system InP/InGaAsP is used for manufacturing the filter.
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Borges, Vinícius S., Erivelton G. Nepomuceno, Carlos A. Duque, and Denis N. Butusov. "Some Remarks about Entropy of Digital Filtered Signals." Entropy 22, no. 3 (March 23, 2020): 365. http://dx.doi.org/10.3390/e22030365.
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The finite numerical resolution of digital number representation has an impact on the properties of filters. Much effort has been done to develop efficient digital filters investigating the effects in the frequency response. However, it seems that there is less attention to the influence in the entropy by digital filtered signals due to the finite precision. To contribute in such a direction, this manuscript presents some remarks about the entropy of filtered signals. Three types of filters are investigated: Butterworth, Chebyshev, and elliptic. Using a boundary technique, the parameters of the filters are evaluated according to the word length of 16 or 32 bits. It has been shown that filtered signals have their entropy increased even if the filters are linear. A significant positive correlation (p < 0.05) was observed between order and Shannon entropy of the filtered signal using the elliptic filter. Comparing to signal-to-noise ratio, entropy seems more efficient at detecting the increasing of noise in a filtered signal. Such knowledge can be used as an additional condition for designing digital filters.
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Havis, Azhar Al, and Liza Fitria. "Filtering Sinyal Menggunakan Band Pass Filter." Jurnal SIFO Mikroskil 19, no. 2 (May 29, 2018): 37–48. http://dx.doi.org/10.55601/jsm.v19i2.594.
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In our daily lives we find many filters, filters from the word itself are filters. Filters vary, there are air filters to filter dirty air to be clean, filters / filters for coffee and tea to filter coffee or tea pulp, and so on. All of them try to filter something to get what we want. The filter here is a frequency filter, from which the filter will filter the frequency. The existing frequency we filter so get the frequency as we want. In this research, signal filtering will be carried out using Band Pass. The band-pass filter will pass signals with frequencies in a certain range and reduce the signal with other frequencies. The sound sample used is the sound of a cat with just one sample. In this sample signal screening is carried out with 5 different frequencies, namely at frequencies of 8000, 16000, 32000, 48000 and 96000. Data retrieval and processing of voice signals are carried out with the help of audacity and Matlab R2010b software. Sound data in the .wav format is filtered to remove noise and filter using a band pass filter. Sounds issued that are received are destructive which eliminate the sound information that is carried. This of course requires that the sound quality received is not good, so it requires sound signal processing to eliminate noise. Then the voice data is processed by voice signal using the FFT (Fast Fourier Transform) method. The results of this study are the output of sound signals that are clean from noise.
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Hromić- Jahjefendić, Altijana, Selma Kozarić, Adna Hrapović, Aiša Trebo, Ajla Tipura, and Muhamed Adilović. "Comparison of Brita and Profissimo water filters." Heritage and Sustainable Development 5, no. 1 (June 30, 2023): 151–58. http://dx.doi.org/10.37868/hsd.v5i1.177.
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This research was focused on testing two water filters - Brita and Profissimo, which were filtering two and five liters of water every day. The lifespan of used filters is four weeks, while they have been actively used for eight weeks in this study to check for their efficiency after exceeded usage. Along with this, the quality of tap water, which was filtered using these two types of filters, was also tested. The experiment of the whole study was divided into three main stages: microbiological analysis, biochemical analysis, and UV-VIS spectrophotometric analysis of filtered water. The measurements were done every five days. The aim was to compare the performances of Brita and Profissimo filters after the completion of the required experiments. Based on the results that are obtained from all the analyses mentioned previously, we can conclude that Brita 2l filter was the most efficient, while Profissimo 5l filter appeared to be the least effective filter. It is important to emphasize that the tap water in Sarajevo is generally clean and drinkable, so there is a possibility that when using more polluted water, greater deviations in the operation of filters can be observed. Overall, both water filters were usable even after two months of active usage and our measurements showed good water quality which lacks impurities and is safe for drinking.
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Kang, Wei, Li Xia Zhang, and Ji Bo Wan. "Matching Characteristic of Constant Voltage Source Excited Filter in Power System." Applied Mechanics and Materials 427-429 (September 2013): 1072–75. http://dx.doi.org/10.4028/www.scientific.net/amm.427-429.1072.
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Filters between voltage source converter and the batteries in power system can be categorized into constant voltage source excited filters. The paper discusses the importance of the matched structure and parameters for power filters. The relation between matched structure and filters output characteristic is demonstrated and the design principle is introduced. The work above proved that even if the filters are designed for the same transfer function, so long as filters load resistance is different, their designed parameters are also different. Traditional power system filter seldom consider its both ends load matching characteristic. When the difference between filter's load characteristic and practical system equivalent impedance are large, the actual filtering effect becomes worse, current loss arises and even there may be the possibility of resonance. As the lack of energy resource and energy crisis is gradually becoming a serious problem, energy conservation is important. Constant voltage source excited circuit configuration model is established through the simulation and test. The results show the validity and feasibility of the method that filter should be designed the according to its load characteristic in practical application.
Dissertations / Theses on the topic "Filters"
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Kamoun, Leila. "Etude de filtres MMIC hyperfréquences en technologies GaN et AsGa." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0265/document.
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Ces travaux de thèse portent sur l‟étude de filtres « multi-fonctions » dont l‟objectif serait de réduire les dimensions des circuits réalisant les fonctions de filtrage dans les systèmes aéroportés. Ces travaux ont donc conduit à la réalisation de filtres large bande (2 – 18 GHz) réjecteurs développés en technologie MMIC utilisant la filière GaN, ainsi que des filtres large bande développés suivant la filière AsGa en technologie MMIC. Les différents filtres réjecteurs ont été conçus suivant deux principes :- Le premier basé sur une structure à résonateurs à lignes couplées. Les différents prototypes réalisés ont permis de montrer l‟accordabilité en fréquence grâce à une charge variable placée à l‟extrémité non court-circuité de la ligne couplée. Celle-ci peut être réalisée par une diode varactor ou par un transistor froid. Ces prototypes ont également permis de montrer la possibilité de fonctionner suivant un mode passe-tout ou un mode réjecteur par simple polarisation de transistors chargés à l‟extrémité de la ligne couplée.- Le second est basé sur l‟accordabilité de filtres actifs par commutation entre plusieurs canaux à l‟aide d‟une structure distribuée. Un prototype a été développé et réalisé en technologie AsGa. Cette structure permet à la fois une accordabilité en fréquences, ainsi qu‟en largeur de bande passante (par activation de plusieurs canaux de bandes passantes adjacentes), et une adaptation large bande. Cette structure réunit à la fois des fonctions d‟accordabilité en fréquences (entre 8,7 et 15,6 GHz) par polarisation d‟éléments actifs, ceux-ci permettant même d‟obtenir du gain (de l‟ordre de 10 dB)The aim of this work is to study “multi-functions” filters with an objective to reduce the dimensions of the circuits used for filtering functions in airborne systems. This work allows to obtain wide band notch filters (from 2 to 18 GHz) developed in MMIC technology using theEtude de Filtres MMIC Hyperfréquences en Technologies GaN et AsGa. 152GaN process and wide band filters developed in GaAs technology. The notch filters have been realized with two principles:- The first one based on coupled lines resonators structure. The prototype manufactured allow to validate the frequency tunability thanks to a variable load placed at the end of the coupled line. This can be realized with a varactor diode or with a cold transistor. These prototypes allow also validating the possibility for the circuit to work as an “allpass” filter or as a notch filter by applying a bias voltage on the transistors placed at the end of the coupled line.- The second one is based on the tenability of active filters by commuting between several channels thanks to a distributed structure. A prototype has been developed and manufactured in GaAs technology. This structure allow a frequency tunability with also the possibility to tune the bandwidth (by activating seeral channels with edge bandwidth), and a wide band matching. This structure allows to obtain frequency tunability (between 8.7 and 15.6 GHz) by applying a bias voltage on the active elements which brin gain (around 10 dB)
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Demirsoy, Süleyman Sırrı. "Complexity reduction in digital filters and filter banks." Thesis, University of Westminster, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433680.
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Maas, Susan. "Coaxial resonator filters." Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/18067.
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Thesis (MScEng)--Stellenbosch University, 2011.ENGLISH ABSTRACT: The purpose of this project is to develop a number of coaxial resonator lters. Firstly, the theoretical model of the lter is discussed, with a Tchebyscheff LC-ladder prototype lter used to derive a generalised bandpass lter. From this, generalised Combline- and Interdigital lters are derived. Following this, various options and limitations in the mechanics of microwave lters are discussed. Results are shown for an in-depth study considering the unloaded quality factor for thirteen di erent resonators. Each resonator is unique in the method of manufacturing, polishing, as well as plating. Utilizing the information obtained from the unloaded quality factor measurements, three coupled coaxial resonator lters, are designed for use in a radar system, namely a sixth order 2125 MHz Combline lter, a sixth order 9250 MHz Interdigital lter and a third order 9250 MHz Interdigital lter. Optimal results were obtained when both resonators and coupled transmission line lters were constructed from aluminium that was wire-cut and then silver electroplated.
AFRIKAANSE OPSOMMING: Die omvang van hierdie projek behels die ontwerp en bou van ko-aksiale resoneerder filters. Eerstens word die teoretiese modellering van die lters bespreek. 'n Tchebyscheff LC-leer prototipe filter word gebruik as basis vir 'n generiese banddeurlaat filter. Die banddeurlaat lter word gebruik om die afgeleide Kamlyn- en Interdigitale filter te de finieer. Hierna volg 'n bespreking aangaande die verskillende moontlikhede in die meganiese vervaardiging van mikrogolf filters. 'n Gedetailleerde studie word gedoen om die onbelaste kwaliteitsfaktore van 13 verskillende resoneerders te bepaal. Elkeen van hierdie resoneerders is uniek in die metode van vervaardiging, polering, asook die platering daarvan. Deur gebruik te maak van die resultate van die onbelaste kwaliteitsfaktore, word drie gekoppelde ko-aksiale resoneerder filters ontwikkel vir die gebruik in 'n radarstelsel, naamlik 'n sesde-orde 2125 MHz Kamlyn lter, 'n sesde orde 9250 MHz Interdigitale filter, asook 'n derde orde 9250 MHz Interdigitale filter. Die beste resultate was gevind toe beide resoneerders en gekoppelde ko-aksiale resoneerder filters vervaardig is uit aluminium wat gedraadsny en silwer geplateer is.
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Giménez, Bonastre Alfred Raul. "RF filters and multiplexers based on acoustic wave technologies with ladder-type and cross-coupled topologies. Designing under a systematic strategy." Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/399512.
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La tecnologia mòbil ha emergit com la plataforma de major èxit per a la implantació de serveis innovadors i aplicacions d’usuari tant des d’un punt de vista tecnològic com econòmic. Els dispositius mòbils estan modificant els hàbits de comportament de les persones i veiem contínuament com, en aquest sentit, la nostra societat millora dia a dia. Amb la xarxa 4G en ple procés de desplegament i els futurs estàndards 5G en ple desenvolupament, la demanda global per al servei de dades de banda ampla ha estat sotmesa a un cicle de creixement imparable. I continuarà així alimentat per la ubiqüitat del servei, segons les previsions del Cisco. El més important ´es que aquest creixement indubtablement demostra la importància de la banda ampla per als ciutadans, la societat i l’economia, mentre dibuixa un gran repte als proveïdors de serveis de xarxa.
L’objectiu d’aquest treball està centrat en el desenvolupament de tècniques de síntesi per al disseny de dispositius filtrants basats en tecnologies micro-acústiques, enfocant així el gran repte de gestió de l’espectre freqüencial en el segment d’usuari. En general, el disseny d’aquest tipus de dispositius es basa en tècniques d’optimització degut a les rigoroses limitacions imposades per la viabilitat tecnològica dels ressonadors acústics, així com a les exigents especificacions de rendiment del dispositiu. És per aquests motius que el disseny i fabricació de filtres i duplexors basats en tecnologia acústica creen un gran repte cada cop més difícil d’assolir. En aquest treball es proporcionen metodologies sistemàtiques enfocades en millorar i fer més eficient el disseny de dispositius filtrants basats en ressonadors acústics.
El més important durant el disseny de filtres i duplexors basats en tecnologia acústica ´es que els ressonadors siguin viables tecnològicament. Les diferents metodologies presentades en aquest treball són útils per a la síntesi de topologies en escalera o xarxes amb acoblaments creuats on la viabilitat tecnològica ´es un requisit indispensable en totes les solucions proporcionades. El coeficient d’acoblament de cada ressonador, les freqüències de ressonància, el factor de qualitat, l’energia emmagatzemada, o l’àrea del xip son paràmetres que es tenen en compte durant el disseny d’aquest tipus de dispositius. Mitjançant les tècniques de síntesi proporcionades en aquest treball, no només es controlen analíticament aquestes restriccions, sinó que s’obtenen resultats òptims en el mínim temps i cost computacional.
L’ús d’aquestes tècniques, a més, permet un control dels paràmetres de fase essencial per al disseny de multiplexors, els quals estan en el punt de mira com a dispositiu indispensable dins les capçaleres dels futurs sistemes sense fils preparats per treballar amb el protocol de Carrier Aggregation dins els estàndards 4G-Advanced i 5G. Dispositius filtrants, duplexors i multiplexors viables tecnològicament i complint amb les especificacions de màscara freqüencials són resultat de l’ús de les metodologies proposades en aquest treball.The mobile technology has emerged as the most successful platform for the introduction of innovative services and user applications from both a technological and economical perspective. Mobile devices are changing the habits of the people and it is possible to see how, in this sense, our society is continuously improving. With the 4G network in process of deployment and the future 5G standards under development, global demand for broadband data services has been subjected to a series of unstoppable growth. And it will continue increasing pushed by the ubiquity of the service, according to Cisco's forecasts. The most important is that this growth undoubtedly demonstrates the importance of broadband services for the people, society, and economy, while it is drawing a major challenge for the network service providers. The aim of this work is to develop synthesis techniques for the design of filtering devices based on micro-acoustic technologies, focusing therefore the great challenge of frequency spectrum management in the user segment. In general, the design of these filtering devices is based on optimization techniques because of the stringent requirements imposed by the technological feasibility of acoustic resonators and the tight performance specifications of the device. For this reason, the design and manufacture of filters and duplexers based on acoustic resonators becomes a huge challenge increasingly difficult to achieve. In this work, systematic methodologies are presented in order to improve and make more efficient the design of filtering devices based on micro-acoustic technologies. The most important consideration during the synthesis of filters and duplexers is that the resonators must be technologically feasible. The methodologies presented in this work are useful for the design of ladder-type filters and cross-coupled prototypes in which the technological feasibility is an essential requirement for all the provided solutions. The effective coupling coefficient of each resonator, the resonant frequencies, the quality factor, the stored energy, or the chip size are parameters to consider during the design of micro-acoustic filters. By means of the techniques provided in this work, all these restrictions are analytically managed, and optimum results are obtained with a minimum time and computational effort. Moreover, the use of these synthesis techniques allows the control of the phase parameters, which are essential for the design of multiplexer devices. These are considered the main device for the future radio-frequency front-end modules ready to work with Carrier Aggregation and the 4G-Advanced and 5G standards. Stand-alone filtering devices, duplexers, and multiplexers, ready to accommodate the micro-acoustic technological requirements and satisfying the frequency mask specifications, as long as possible, are the result of the proposed methodologies in this work.
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Mlích, Jozef. "Sledování objektů ve videosekvencích." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2008. http://www.nusl.cz/ntk/nusl-235922.
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In this master thesis, image processing methods and methods for statistical modeling of motion are presented. First, description methods of image processing, such as background subtraction method used for object detection, are presented. Next, description of morphological operations, such as dilatation and erosion, is done. Finally, methods for statistical modeling, such as Kalman filter and particle filters, are shown.
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Basti, Ahmed. "Développement de méthodes de synthèse pour la conception de filtres hyperfréquences compacts et optimisés en pertes." Thesis, Limoges, 2014. http://www.theses.fr/2014LIMO0023/document.
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Pour les systèmes de communication par satellite, des filtres avec de très bonnes performances électriques sont indispensables afin de rejeter les signaux indésirables dans de nombreuses parties de la chaîne de communication. Les technologies fort-Q peuvent répondre à cette exigence mais elles conduisent souvent à des dispositifs encombrants. D'autre part, les technologies compactes faible-Q souffrent généralement d'une dégradation des performances électriques en termes de pertes d'insertion, de sélectivité et de platitude. Pour répondre à une demande croissante concernant la réduction de la taille, il est essentiel de développer des filtres hyperfréquences compacts avec des performances électriques améliorées.Pour le filtre de réception, le défi est de concevoir un filtre passe-bande compact avec une réponse plate dans la bande passante et une forte réjection hors bande. Les pertes d'insertion ne sont pas cruciales et peuvent être compensées par un amplificateur en laissant ainsi un espace pour la conception de filtre à pertes. Un tel filtre accepte des pertes supplémentaires, qui peuvent être distribués dans le réseau afin de fournir une transmission plate dans la bande passante et une forte sélectivité hors bande.Dans le cadre de cette thèse, des nouvelles méthodes de synthèse de dispositifs de filtrage ont été étudiées et développées dans le but d’améliorer les performances tout en conservant un encombrement réduit. Ces méthodes ont été validées pour la conception de filtres de récepteur dans la charge utile de satellites de télécommunication dans le cadre d’une collaboration entre le laboratoire Xlim, le Centre National d’Etudes Spatiales et Thales Alenia SpaceFor satellite communication systems, high performance filters are needed in order to reject unwanted signals in many parts of the communication chain. High quality factor (Q) technologies can meet this requirement, but they often lead to bulky devices. On the other hand, compact technologies are generally low Q and suffer from a degradation of electrical performances in terms of insertion loss, selectivity and flatness. To meet a growing demand concerning size reduction, it is essential to develop compact microwave filters with improved electrical performances.For a receive filter, the challenge is to design a compact bandpass filter with a flat response in the passband and a sharp transition in the passband edges. The insertion loss is not crucial and it can be compensated by the amplifier, leaving a room to the design of a lossy filter. Such a filter accepts additional losses, which can be distributed in the network in order to provide a flat transmission in the passband and a sharp selectivity.In this thesis, new synthesis methods for filtering devices have been studied and developed to improve performances while maintaining a small footprint. These methods have been validated for the design of filters for a receiver in payload satellites as part of collaboration between the Xlim laboratory, the France National Space Centre and Thales Alenia Space
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Nikolina, Janković. "Mikrotalasni filtri sa više nezavisno kontrolisanih propusnih opsega realizovani u mikrostrip arhitekturi." Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2013. https://www.cris.uns.ac.rs/record.jsf?recordId=83681&source=NDLTD&language=en.
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Filtri predstavljaju nezaobilazan deo svakog mikrotalasnog uređaja. Skorašnji veoma brz razvoj bežičnih sistema pred mikrotalasne filtre postavlja nove zahteve kao što su visoke performanse, kompaktnost i rad na više proizvoljno odabranih učestanosti koje se mogu nezavisno kontrolisati.Naučni doprinos ove doktorske disertacije predstavlja pet novih konfiguracija mikrotalasnih multi-band filtara koji su realizovani u mikrostrip arhitekturi. Od toga tri konfiguracije predstavljaju dual-band filtre, a preostale dve konfiguracije tri-band filtre. Filtri su realizovani korišćenjem fraktalnih krivih i/ili savijenih λ/4 rezonatora, i to u klasičnoj tehnologiji štampanih ploča i u višeslojnoj tehnologiji nisko-temperaturne zajedno pečene keramike.Detaljno je analiziran i opisan način rada predloženih filtara. Filtri su fabrikovani, a njihove performanse izmerene i upoređene sa drugim rezultatima dostupnim u literaturi. Pokazano je da predložene filtre karakteriše mogućnost nezavisne kontrole propusnih opsega što je iskorišćeno za realizaciju dual-band filtara koji rade na WLAN 2.4/3.5 GHz opsezima i tri-band filtara koji rade na WLAN 2.4/3.5/5.2 GHz opsezima. Štaviše, predložene tri-band strukture predstavljaju najmanje tri-band filtre do danas predložene u literaturi.Filters are indispensable components in any microwave device. Recent rapid development of wireless systems posed new demands to microwave filters, such as high performance, compact size and the ability to simultaneously operate on several independently selected frequencies.Scientific contribution of this dissertation are five novel microwave multi-band filters realized in microstrip architecture. Out of the five, three configurations are dual-band filters, while the remaining two are tri-band filters. Filters are designed using fractal curves and/or folded λ/4 resonators, in the conventional printed circuits technology or in low-temperature cofired ceramics technology.Operating principles of the proposed filters have been analyzed and explained in detail. Their performances have been measured and compared to other recently published results. It has been shown that the proposed filters allow independent control of the passbands. This has been used to design dual-band filters operating at WLAN frequencies of 2.4/3.5 GHz and tri-band filters operating at WLAN frequencies of 2.4/3.5/5.2 GHz. Moreover, the proposed tri-band filters are the most compact tri-band filters published so far.
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Rosenbaum, Linnea. "On low-complexity frequency selective digital filters and filter banks." Doctoral thesis, Linköpings universitet, Elektroniksystem, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8930.
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En filterbank består av flera filter som arbetar tillsammans för att dela upp en signal i olika frekvensband. De kan också användas för att slå ihop signaler separerade i frekvensplanet till en enda. Sedan tidigt 70-tal har man lärt sig att designa förlustfria filterbankar som alltså inte introducerar några som helst fel i systemet. Sådana filterbankar kallas PR-filterbankar, där PR står för 'perfekt rekonstruktion'. Exempel på applikationer där filterbankar används är bildkodning, audiokodning, kommunikationssystem och omvandling av analoga signaler till digitala (A/D-omvandling). Under de senaste åren har det framkommit att genom att lätta på kraven gällande perfekt rekonstruktion, går det att markant minska den erforderliga aritmetiska komplexiteten. Eftersom de flesta system i sig inte är förlustfria, kan man utan att egentligen påverka den totala prestandan tillåta små fel i filterbanken, så l¨ange dessa fel är försumbara i jämförelse med andra felkällor som t.ex. kvantisering och avrundning. Avhandlingen behandlar digitala filter och likformiga icke-PR-filterbankar. Merparten av filterbankarna är realiserade med någon slags moduleringsteknik (cosinus-, sinus- eller komplexmodulering). Den röda tråden genom avhandlingen är kombinationen av tämligen smala övergångsband och samtidigt låg aritmetisk komplexitet. Ett sätt att uppnå denna kombination är att använda sig av en teknik som heter frekvenssvarsmaskning och förkortas FRM. Denna metod har på ett framgångsrikt sätt använts i avhandlingen. En potentiell nackdel med FRMmetoden är att den medför en längre fördröjning genom systemet. Därför föreslås också ett sätt att syntetisera FRM-filter med låg fördröjning. Här optimeras filtren både med avseende på komplexitet och fördröjning samtidigt. En annan metod som utnyttjats för att kombinera relativt smala övergångsband med låg aritmetisk komplexitet är att använda IIR filter istället för FIR filter. Ett flertal exempel på filter och filterbankar, optimerade och syntetiserade i Matlab, illustrerar fördelarna med de föreslagna filter- och filterbanks-klasserna.Filter banks are systems of several filters with a common input or a common output. They are used whenever a signal needs to be split into different frequency bands. Since the early seventies, the theory of digital filter banks has developed to a mature state. Today there exist numerous ways to design filter banks for different applications, such as image and audio coding, transmultiplexing in communication systems, echo cancellation, and analog-to-digital (A/D) conversion systems. However, earlier work has to a large extent been on the transfer function level, whereas in this thesis work, efficient realizations, important in e.g. low-power applications, are in focus. Further, most of the previous work have been focused on the perfect reconstruction (PR) case, which is, for many applications an unnecessarily severe restriction. It has been show that by relaxing the requirements on perfect reconstruction, and allowing the filter banks to have some errors, the arithmetic complexity can be reduced significantly. This thesis treats digital filters and uniform non-PR filter banks. A major part of the filter banks are realized using different modulation schemes (complex, cosine, or sine modulation). The governing idea through the thesis is the combination of frequency selectivity and low arithmetic complexity. One example on how to achieve frequency selective digital filters and filter banks with low arithmetic complexity is to use the frequency-response masking (FRM) approach. This approach together with the idea of using IIR filters instead of FIR filters is successfully used in the thesis. The price to pay for the reduced arithmetic complexity using FRM filters is unfortunately a longer overall delay. Therefore, some work has ben done in the field of low-delay FRM FIR filters as well. These filters are optimized on both low delay and low arithmetic complexity simultaneously. A number of design examples are included in order to demonstrate the benefits of the new classes of filters and filter banks.
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Rosenbaum, Linnéa. "On low-complexity frequency selective digital filters and filter banks /." Linköping : Department of Eelectrical Engineering, Linköpings universitet, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8930.
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Anderson, Martin S. "Design of two-dimensional PCAS digital filters and filter banks." Thesis, University of Warwick, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307968.
Full textBooks on the topic "Filters"
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Hamming, R. W. Digital filters. Mineola, N.Y: Dover Publications, 1998.
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Hamming, R. W. Digital filters. 3rd ed. Englewood Cliffs, N.J: Prentice Hall, 1989.
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Hamming, R. W. Digital filters. 3rd ed. Englewood Cliffs, N.J: Prentice Hall, 1989.
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Newling, John. Filters. Halifax: Henry Moore Sculpture Trust Studio, Dean Clough, 1990.
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Babington, Mary F., Tonia P. Bell, Jennifer L. Mapes, and Diana E. Kole. Filters. Cleveland: Freedonia Group, 2000.
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McGinn, Martin. Filters. London: Curwen Gallery, 1990.
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Modern filters. New York: Macmillan, 1989.
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Schlichthärle, Dietrich. Digital Filters. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-14325-0.
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Su, Kendall L. Analog Filters. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4615-2051-1.
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Schlichthärle, Dietrich. Digital Filters. Berlin, Heidelberg: Springer Berlin Heidelberg, 2000. http://dx.doi.org/10.1007/978-3-662-04170-3.
Full textBook chapters on the topic "Filters"
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Keller, Reto B. "Filtering." In Design for Electromagnetic Compatibility--In a Nutshell, 245–63. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-14186-7_15.
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AbstractIn EMC, filtering helps to minimize emissions of a product and increase the product’s immunity against electromagnetic interference. This chapter presents the concepts of determining the right filter type and ensuring the proper components are chosen regarding power dissipation, noise current type, and high-frequency behavior.Filters can be classified according to their attenuation in the frequency-domain: Low-pass filters High-pass filters Band-pass filters Band-stop filters or according to active components involved or not: Passive filters Active filters or according to the noise current type: Differential-mode noise filters Common-mode noise filters or according to the suppression of transients: ESD filters Burst filters Surge filters or according to the implementation in hardware or software: Analog filters (hardware) Digital filters (software) In this chapter, all the filter types listed above are explained in further detail.
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Bauer, Thomas. "Filters." In Thermophotovoltaics, 35–51. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-19965-3_3.
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Burger, Wilhelm, and Mark J. Burge. "Filters." In Texts in Computer Science, 89–119. London: Springer London, 2016. http://dx.doi.org/10.1007/978-1-4471-6684-9_5.
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Mailund, Thomas. "Filters." In Introducing Markdown and Pandoc, 99–131. Berkeley, CA: Apress, 2019. http://dx.doi.org/10.1007/978-1-4842-5149-2_11.
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Owyang, Gilbert H. "Filters." In Foundations for Microwave Circuits, 761–874. New York, NY: Springer New York, 1989. http://dx.doi.org/10.1007/978-1-4613-8893-7_14.
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Ugurlu, Tugberk, Alexander Zeitler, and Ali Kheyrollahi. "Filters." In Pro ASP.NET Web API, 289–324. Berkeley, CA: Apress, 2013. http://dx.doi.org/10.1007/978-1-4302-4726-5_11.
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Lazzarini, Victor. "Filters." In Computer Music Instruments II, 235–48. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-13712-0_16.
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Duffy, Frank H., Vasudeva G. Iyer, and Walter W. Surwillo. "Filters." In Clinical Electroencephalography and Topographic Brain Mapping, 29–36. New York, NY: Springer New York, 1989. http://dx.doi.org/10.1007/978-1-4613-8826-5_4.
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Freeman, Adam. "Filters." In Pro ASP.NET Core MVC, 581–620. Berkeley, CA: Apress, 2016. http://dx.doi.org/10.1007/978-1-4842-0397-2_19.
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Mediavilla, A. "Filters." In Microwave Devices, Circuits and Subsystems for Communications Engineering, 379–459. Chichester, UK: John Wiley & Sons, Ltd, 2006. http://dx.doi.org/10.1002/0470012757.ch6.
Full textConference papers on the topic "Filters"
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Sappok, Alexander, Vincent Costanzo, Leslie Bromberg, Cole Waldo, and Rob Salsgiver. "Vibration-Induced Ash Removal From Diesel Particulate Filters." In ASME 2014 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icef2014-5570.
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Ceramic, honeycomb-type diesel particulate filters (DPF) are commonly used in a wide range of on- and off-road diesel-powered vehicles and equipment to reduce particulate matter (PM) emissions to mandated levels. While the majority of the trapped PM can be removed from the filter through regeneration, incombustible ash builds up in the filter over time. The ash deposits are generally found accumulated in a porous layer along the channel walls, or packed as end-plugs towards the back of the filter channels. Ash accumulation in the filter restricts exhaust flow, reduces the filter’s soot storage capacity, and negatively impacts fuel consumption. In order to mitigate these deleterious impacts on filter operation, the particulate filter is periodically removed for ash cleaning. This study examines the effects of vibrations to remove and dislodge ash deposits from diesel particulate filters, particularly the ash accumulated toward the back of the channels and packed in plugs. Fundamental measurements of ash properties, combined with experiments utilizing full-size, field-aged particulate filters were conducted to ascertain the effects of specific vibration frequencies and acceleration levels on ash plug break-up and transport out of the DPF channels. The results show considerable potential for the application of controlled vibrations in an offline cleaning system to aid in the removal of ash deposits plugging filter channels, thereby reducing the ash-related impact on vehicle fuel consumption and extending the useful life of the particulate filter.
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Sharp, G., Kristina M. Johnson, and D. Doroski. "Ferroelectric liquid crystal tunable filters." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1989. http://dx.doi.org/10.1364/oam.1989.ths1.
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Rapidly tunable optical filters have applications in remote sensing, signal processing, colorimetry, color displays, and communications. In this paper we present simulation and experimental results of electronically tunable filter structures employing smectic A* electroclinic and smectic C * liquid crystals. The first FLC tunable filter demonstrated1 used smectic C * material in a Lyot filter2 geometry and was discretely tunable between two bands centered at 440 and 660 nm. Current research aimed at making continuously tunable structures with narrow bandwidths, tunability over a free spectral range, high throughput, and large aperture is described. Computer simulations are used to analyze the devices using network synthesis techniques.3
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Pond, B. J., and Charles K. Carniglia. "Rugate filters as minus filters." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1988. http://dx.doi.org/10.1364/oam.1988.waa2.
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Thelen1 has developed a simple technique for improving the off-band transmittance of minus filters (or notch filters). This technique involves placing the filter between two substrates with reflective indices equal to the lowest index in the interference filter. Additional layers using the low index and an intermediate index are added on either side of the original layers to form a symmetrical structure. These antireflective layers improve the performance on both sides of the rejection band. A similar technique can be used if the structure of the filter is rugous, i.e., has a sinusoidal variation. Additional sinusoidal periods having an intermediate refractive index can be added on either side of the original rugate filter. The performance can be improved by proper choice of the intermediate index and the number of periods added. This design is somewhat simpler than a similar technique which has been proposed.2
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Freeman, William T., Edward H. Adelson, and Eero P. Simoncelli. "Steerable filters for image analysis." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1989. http://dx.doi.org/10.1364/oam.1989.mjj4.
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We present a method to synthesize filters tuned for spatial frequency and orientation as linear combinations of a set of basis filters, allowing an efficient architecture for filtering and analyzing images with oriented filters. Using this technique, one can design filters which allow adaptive control of both the orientation and phase of a filter simply by changing the linear weightings in a sum of basis filters. The number of basis filters required depends on the polynomial order n of the filter, after modulation by a windowing function. Filter functions of even or odd parity require n + 1 basis filters; functions of mixed parity require 2n + 1 basis filters. Filters similar to those found in the visual cortex form a good basis set for image analysis. Steerable filters have application in the analysis of texture and local orientation; they can also be adapted for shape-from-shading analysis in a variant of Pentland's linear shape-from-shading scheme.
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Dickey, Fred M., and Louis A. Romero. "Consequences of the normalization of correlation filters." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/oam.1990.thtt7.
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The technique of using correlation filters for optical pattern recognition has received considerable study.1 Several variations on the matched filter have been suggested. They include phase-only filters (POFs), binary phase-only filters (BPOFs), complex ternary matched filters (CTMFs) and synthetic discriminate functions (SDFs). Generally, in the development of optical correlation filters, little attention has been given to the normalization of the filter output. Goodman suggested that the matched filter be normalized by means of the Cauchy–Schwarz inequality.2 The Cauchy–Schwarz inequality can be applied to arbitrary correlation filters. This normalization achieves intensity invariance. It can be seen that the matched filter achieves the maximum normalized value of unity. For all other correlation filters, a value less than unity is obtained. In general, it can be shown that for filters other than the matched filter, there are objects that give normalized correlation outputs greater than the object for which the filter was made. This simple normalization has consequences for the design, bandwidth selection, and discrimination ability for the above mentioned filters. The results of analysis and simple examples will be presented.
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Downie, John D. "Ternary phase and amplitude synthetic discriminant function filters." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/oam.1991.thx2.
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The use of synthetic discriminant function filters (SDFs) has long been proposed as a means of achieving distortion-invariant pattern recognition in optical correlators. Various design algorithms have been developed toward this end, including binary phase-only SDFs that can be readily implemented with current types of spatial light modulator. Recently, optical filters have been developed in which certain of the binary filter’s pixels are blocked to achieve a ternary state filter.1 These filters have been demonstrated to provide better correlation discrimination between the in-class object and an out-of-class object. In this work we design ternary phase and amplitude synthetic discriminant function filters in simulation with an algorithm that allows equal correlation peaks to be obtained for in-class objects while suppressing the responses from out-of-class objects, relative to the discrimination ratios achieved with binary phase-only SDFs. We investigate issues pertinent to practical systems’ use including variations in the design procedure, the degree of discrimination improvement afforded, response level of images between the training set images, maximum distortion range possible and signal-to-noise considerations.
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Arsenault, Henri H., and Luc Leclerc. "Sldelobe-reduclng Invariant composite filters." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1987. http://dx.doi.org/10.1364/oam.1987.mw7.
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Composite filters, which are linear combinations of matched filters, allow arbitrary correlation peaks to be obtained for any objects but are usually associated with large sidelobes. This problem Is compounded when the composite filters are composed of circular harmonic rotation-invariant filters,1 because such filters trade off the SNR for rotation invariance. One way to reduce sidelobes is to make a filter that minimizes the mean-square difference between the outputs of two filters: One Is designed to recognize a given object and to discriminate against another given object. The other Is designed to discriminate against noise. The combined filter yields good sidelobe reduction.
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Mahlab, Uri, and Joseph Shamir. "Phase-only entropy optimized filter by simulated annealing." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1989. http://dx.doi.org/10.1364/oam.1989.tuc5.
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The recently introduced concept of entropy optimized filters1 led to optical correlators of very good discrimination even in the presence of substantial noise. Various numerical procedures were found to be quite effective in the generation of regular holographic filters. However, the convergence of most of these algorithms was inadequate for phase-only filters due to the fast variations in these filters. In this work we show that procedures of simulated annealing are suitable also for the generation of phase-only filters leading to high quality performance. To improve the process of filter generation, electrooptic architectures are proposed for their implementation.
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Hall, Randolph L. "Gradient Index Bandpass Filters." In Optical Interference Coatings. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/oic.1992.otub2.
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The performance of filters having sinusoidal refractive index profiles have been published by various authors1. In general, these filters have a strong reflection at the design wavelength and offer the promise of no harmonics at any wavelength2. Further, these refractive index profiles may be superimposed with each other creating multiple stopbands. Fig. 1 shows the refractive index profile and predicted performance of this type of filter, commonly referred to as a rugate (from the Latin for wrinkled) filter. Presented in this paper is an approach for the design of narrow bandpass filters based on this type of refractive index profile. These filters are suitable for applications which require very narrow passbands.
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Freeman, William T., and Edward H. Adelson. "Extensions of steerable filters." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/oam.1990.mt2.
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We present new extensions of steerable filters for image analysis. The architecture permits oriented filters to be applied efficiently over a continuous range of angles. The outputs of several basis filters give an analytic expression for the filter response as a function of angle. We extend our previous analysis to include three-dimensional image filters. The resulting local analysis of the orientation and the phase of volumetric data may be usefully applied to medical imagery and motion sequences. The approach permits considerable computational savings, because a small number of x–y–z separable filters can be used to synthesize an x–y–z nonseparable filter of arbitrary orientation. We also develop techniques for the analysis of multiple orientations at a single point, which are applicable to the analysis of orientation of transparent or occluding surfaces.
Reports on the topic "Filters"
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Karns, Tristan, Kirk Reeves, and Murray Moore. Filter Test System for Nuclear Container Filters. Office of Scientific and Technical Information (OSTI), October 2020. http://dx.doi.org/10.2172/1673345.
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Taylor, S., J. Lever, K. Burgess, R. Stroud, D. Brownlee, L. Nittler, A. Bardyn, et al. Sampling interplanetary dust from Antarctic air. Engineer Research and Development Center (U.S.), February 2022. http://dx.doi.org/10.21079/11681/43345.
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We built a collector to filter interplanetary dust particles (IDPs) larger than 5 µm from the clean air at the Amundsen Scott South Pole station. Our sampling strategy used long duration, continuous dry filtering of near-surface air in place of short duration, high-speed impact collection on flags flown in the stratosphere. We filtered ~107 m³ of clean Antarctic air through 20 cm diameter, 3 µm filters coupled to a suction blower of modest power consumption (5–6 kW). Our collector ran continuously for 2 years and yielded 41 filters for analyses. Based on stratospheric concentrations, we predicted that each month’s collection would provide 300–900 IDPs for analysis. We identified 19 extraterrestrial (ET) particles on the 66 cm² of filter examined, which represented ~0.5% of the exposed filter surfaces. The 11 ET particles larger than 5 µm yield about a fifth of the expected flux based on >5 µm stratospheric ET particle flux. Of the 19 ET particles identified, four were chondritic porous IDPs, seven were FeNiS beads, two were FeNi grains, and six were chondritic material with FeNiS components. Most were <10 µm in diameter and none were cluster particles. Additionally, a carbon-rich candidate particle was found to have a small ¹⁵N isotopic enrichment, supporting an ET origin. Many other candidate grains, including chondritic glasses and C-rich particles with Mg and Si and FeS grains, require further analysis to determine if they are ET. The vast majority of exposed filter surfaces remain to be examined.
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Holmes, B. L., and M. A. Janney. Ceramic filters. Office of Scientific and Technical Information (OSTI), December 1995. http://dx.doi.org/10.2172/220576.
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Passmore, Brandon Scott, Eric Arthur Shaner, and Todd A. Barrick. Plasmonic filters. Office of Scientific and Technical Information (OSTI), September 2009. http://dx.doi.org/10.2172/973849.
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Hawley and Thorson. PR-015-15603-R02 Effect of Upstream Piping Components on Ultrasonic Flow Meter Accuracy. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), May 2016. http://dx.doi.org/10.55274/r0010915.
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This project investigated the velocity profile downstream from three commercially available dry gas filters and the effect of this profile on an ultrasonic meter installed in an AGA 9 default configuration. The inlet profile and condition of the filter element were varied to determine the sensitivity on the profile exiting the filter.
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Hawley and Thorson. PR-015-15603-R01 Effect of Upstream Piping Components on Ultrasonic Flow Meter Accuracy - Unblinded. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), May 2016. http://dx.doi.org/10.55274/r0010875.
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This project investigated the velocity profile downstream from three commercially available dry gas filters and the effect of this profile on an ultrasonic meter installed in an AGA 9 default configuration. The inlet profile and condition of the filter element were varied to determine the sensitivity on the profile exiting the filter.
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Lemire, Guy. Absorptive Reflectionless Filters. Portland State University Library, January 2000. http://dx.doi.org/10.15760/etd.7375.
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Mancusi, Joseph E., and Mark Roberson. Tunable HTS Filters. Fort Belvoir, VA: Defense Technical Information Center, June 2002. http://dx.doi.org/10.21236/ada407938.
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Verschoor, Jan, and Leo Lukasse. Functionality of ethylene filters : Effects of filter type and location in reefer. Wageningen: Wageningen Food & Biobased Research, 2016. http://dx.doi.org/10.18174/563048.
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Spain, J. D. Properties of Ceramic Filters. Office of Scientific and Technical Information (OSTI), December 1996. http://dx.doi.org/10.2172/425210.
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