Dissertations / Theses: 'Narrowband'

1

Fortin, Melanie. "Traffic engineering of narrowband networks." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0018/MQ57726.pdf.

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Fortin, Melanie (Melanie Yvette) Carleton University Dissertation Engineering Systems and Computer. "Traffic engineering of narrowband networks." Ottawa, 2000.

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3

Josten, Pål. "Timesynchronization in NATO Narrowband Waveform (NBWF)." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for telematikk, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-23053.

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A common notion of time is essential to avoid collisions in distributed radio networks using TDMA. Local clocks with limited accuracy are normally used to control time in each individual node. These clocks require regular synchronization to prevent the local time of these clocks from diverging. Synchronization of these clocks is controlled by a synchronization algorithm that estimates the correct time based on the information exchanged between nodes.This thesis present a survey of synchronization algorithms that can be used by NATO Narrowband Wave Form (NBWF). NBWF requires that synchronization must be performed without the use of dedicated synchronization messages. It is possible to achieve this by using the correct reception of messages inside certain TDMA slots. Reception of these messages enables the receiving node to estimate the local time of the sender without transmission of an actual timestamp. This information can be used by a synchronization algorithm in the receiving node to estimate the correct local time.The survey of potential synchronization algorithms shows that there are several potential candidates for NBWF. A hybrid algorithm, divided into several layer, fulfills most of the NBWF requirements, and it is the most promising candidate. The actual synchronization of nodes is performed in the lowest layer by Discrete Network Synchronization (DNS) algorithm. Simulations with the DNS algorithm show that this algorithm might not be the optimal choice for NBWF networks. This thesis recommends that a modified version of the hybrid algorithm, utilizing the CS-MNS algorithm in the lowest layer, should be considered for further work with NBWF networks.

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Hsu, Wei-shou 1981. "Robust bandwidth extension of narrowband speech." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82497.

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Telephone speech often sounds muffled and thin due to its narrowband characteristics. With the increased availability of terminals capable of receiving wideband signals, extending the bandwidth of narrowband telephone speech at the receiver has drawn much research interest. Currently, there exist many methods that can provide good reconstructions of the wideband spectra from narrowband speech; however, they often lack robustness to different channel conditions, and their performances degrade when they operate in unknown environments.
This thesis presents a bandwidth extension algorithm that mitigates the effects of adverse conditions. The proposed system is designed to work with noisy input speech and unknown channel frequency response. To maximize the naturalness of the reconstructed speech, the algorithm estimates the channel and applies equalization to recover the attenuated bands. Artifacts are reduced by employing an adaptive and a fixed postfilter.
Subjective test results suggest that the proposed scheme is not affected by channel conditions and is able to produce speech with enhanced quality in adverse environments.

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Barretta, Salvatore. "UAV based Narrowband - Internet of things." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/22761/.

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in this thesis we simulated via Java and Matlab environments a scenario in which a single drone is exploited to carry the NB-IoT base station over an a-priori known area. More specifically, we examined the performance of a drone flying over a area where IoT devices are grouped in clusters and trying to serve as many nodes as possible, with the trajectory solved exploiting the well-known solution of the Travel Salesman Problem (TSP), through which the UAV, that in this study we consider starting from the center of a cluster, finds the minimum path to subsequently reach the center of all the other clusters before reaching again the starting point, where the flight is considered ended. Starting from this assumption we wanted to find the scenario that can best benefit from joint use of NB-IoT and UAV, analyzing both its network throughput and how resources are scheduled by this standard. Then we want to compare the previous results with the new ones obtained changing the way random access is simulated in the code.

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Najafzadeh-Azghandi, Hossein. "Perceptual coding of narrowband audio signals." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0033/NQ64628.pdf.

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Batra, Arun. "Mitigation techniques for severe narrowband interference." Diss., [La Jolla] : University of California, San Diego, 2009. http://wwwlib.umi.com/cr/ucsd/fullcit?p3356201.

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Thesis (Ph. D.)--University of California, San Diego, 2009.
Title from first page of PDF file (viewed June 15, 2009). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 129-139).

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Moncet, Jean-Luc. "Narrowband models of radiation in inhomogeneous atmospheres." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61924.

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Feeney, Thomas Michael. "The complex narrowband UHF mobile radio channel." Thesis, University of Liverpool, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257146.

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Waters, Kevin A. "Narrowband filtering effects on frequency-hopped signals." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Dec%5FWaters.pdf.

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Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, December 2002.
Thesis advisor(s): R. Clark Robertson, Kyle E. Kowalske. Includes bibliographical references (p. 33-34). Also available online.

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Bagchi, Amit G. (Amit Goutam) 1974. "Asynchronous receivers in narrowband packet radio applications." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/43515.

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Sun, Yuhao. "Power optimised narrowband power-line communication systems." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648110.

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Wang, Yazhong. "Stacked Dual Narrowband Organic Near-Infrared Photodetectors." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-139592.

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Compared with the detector devices made of inorganic semiconductors, organic photodetectors are granted with additional strengths, such as flexibility, high scalability and bio-compatibility. However, in the family of organic optoelectronic devices, the detectors that are capable of detecting photons at two or multiple specific wavelengths are still missing. Such photodetectors are highly interesting because they could identify the target objects or materials much more precisely by detecting the reflected, transmitted or emitted photons at two or multiple characteristic wavelengths. In this thesis project, the optical simulations using Transfer Matrix Method (TMM) were performed on the organic devices to achieve the dual wavelength narrowband detection in the near-infrared (NIR) spectral range of 700 ~ 1100 nm. The devices use the fact that, at the interface of the blended organic electron donating and accepting materials, the charge-transfer (CT) states with the transition energies that are lower than the optical gap of the neat materials are formed. Combined with a Fabry-Perot resonant cavity, the CT absorption can be dramatically enhanced at certain wavelengths. The simulation results show that the two detection wavelengths can be tuned independently from 650 to 1100 nm. The spectral resolution (full with at half maximum - FWHM) of the detection bands varies between 10 and 30 nm. The simulated external quantum efficiency (EQE) is ~35% at 700 nm and ~10% at 1000 nm, respectively. A possible application of such photodetectors is for example moisture detection, where two of the characteristic absorption peaks of water are located at around 750 and 960 nm. By optimizing the thickness of the two photo-absorbing layers in a tandem device structure, the detection bands can be tuned to match with those two wavelengths for simultaneous and precise detection.

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Welling, Kenneth. "A Narrowband Model For Aeronautical Telemetry Channels." International Foundation for Telemetering, 1998. http://hdl.handle.net/10150/607359.

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International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California
This paper presents a narrowband channel model appropriate for modeling multipath interference in aeronautical telemetry applications. This model uses a simplified version of Bello’s aeronautical fading channel model [1] with the following three parameters: the specular to direct power ratio T, the direct to diffuse power ratio K and the relative Doppler shift of the specular component. Data taken from Patuxent River NAWC, Edwards AFB and White Sands Missile Range demonstrate that the model is a reasonably accurate statistical representation of the envelope (and power) fluctuations observed in the data. The model works well for those cases where a dominate line-of-sight signal component exists, as well as for those cases where the power in the specular reflections is on the order of the power in the line-of-sight component.

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Andersson, Tomas. "Parameter Estimation and Waveform Fitting for Narrowband Signals." Doctoral thesis, KTH, Skolan för elektro- och systemteknik (EES), 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-235.

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Frequency estimation has been studied for a large number of years. One reason for this is that the problem is easy to understand, but difficult to solve. Another reason, for sure, is the large number of applications that involve frequency estimation, e.g radar using frequency modulated continuous wave (FMCW) techniques where the distance to the target is embedded in the frequency, resonance sensor systems where the output signal is given as the frequency displacement from a nominal frequency, radio frequency identification systems (RFID) where frequency modulation is used in the communication link, etc. The requirement on the frequency estimator varies with the application and typical issues include: accuracy, precision or (bias) processing speed or complexity, and ability to handle multiple signals. A lot of solutions to different problems in this area has been proposed, but still several open questions remain. The first part of this thesis addresses the problem of frequency estimation using low complexity algorithms. One way of achieving such an algorithm is to employ a coarse quantization on the input signal. In this thesis, a 1-bit quantizer is considered which enables the use of low complexity algorithms. Frequency estimation using look-up tables is studied and the properties of such an estimator are presented. By analyzing the look-up tables using the Hadamard transform a novel type of lowcomplexity frequency estimators is proposed. They use operations such as binary multiplication and addition of precalculated constants. This fact makes them suitable in applications where low complexity and high speed are major issues. A hardware demonstrator using the table look-up technique is designed and a prototype is analysed by real measurements. Today, the interest of using digital signal processing instead of analog processing is almost absolute. For example, in testing analog-to-digital converters an important part is to fit a sinewave to the recorded data, as well as to calculate the parameters that in least-squares sense result in the best fit. In this thesis, the sinewave fitting method included in the IEEE Standard 1057 is studied in some detail. Asymptotic Cramér-Rao bounds for three- and four model parameters are derived under the Gaussian assumption. Further, the sinewave fitting properties of the algorithm are analyzed by the parsimony principle. A novel model order selection criterion is proposed for waveform fitting methods in the case of a linear signal model. A generalization of this criterion is made to include the non-linear sinewave fitting application. For multiple sinewave fitting applications two iterative algorithms are proposed. The first method is a combination of the standardized sinewave fit algorithm and the expectation maximization algorithm. The second algorithm is an extension of a single sinewave model to a multiple sinewave model employing the standardized sinewave fitting algorithm. Both algorithms are analysed by numerical means and are shown to accurately resolve multiple sinewaves and produce efficient estimates. Initialization issues of such algorithms are included to some extent.
QC 20100830

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Wu, Qinlin. "Narrowband IoT Networks with Unmanned Aerial Base Stations." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.

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UAV is widely used in civil applications such as environmental hazards monitoring, traffic management and pollution monitoring, all of those contribute to smart city development. Thanks to its high mobility and feasibility, UAVs can be employed as a base station, gathering data from IoT devices distribute in a certain area during its flight. In this case, an appropriate trajectory and suitable parameters set is necessary to achieve better performance. This thesis studies a scenario of NB-IoT machine-type communication network served by an unmanned aerial base station (UAB). In this scenario, the user devices are deployed with Tomas Cluster Process (TCP)[19]. Some of the nodes are named parent nodes and generated with Poisson Point Process (PPP). One single UAB is employed and its trajectory is predefined with a Travelling Salesman Problem model among the parent nodes. All the devices only generate one data packet for UL, whose activation time and expiration time is considered. Due to NB-IoT protocols, the number of resource units available on NPUSCH and the data rate for IoT devices is constrained. This study makes the network throughput and the number of users served as the main basis of performance evaluation, the variation of UAB speed, NPRACH periodicity, deployment variance, and size of the data packet as influencing factors. Finally, we present an analysis of how these parameters affect the overall performance and how the optimal configuration may be chosen according to arbitrary criteria.

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17

Green, Edward. "Propagation characteristics of a narrowband microcellular radio channel." Thesis, University of Southampton, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.480724.

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Martin, P. M. "Advanced linear modem design for narrowband mobile communications." Thesis, University of Bristol, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303851.

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McCarthy, Michael Ronan. "The BUZZ : narrowband ultrasonic positioning for wearable computers." Thesis, University of Bristol, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440047.

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Keskiner, Eser 1979. "An ultrabright, narrowband source of polarization-entangled photons." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/86813.

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Downes, Garfield Orlando. "Characterisation and performance prediction of narrowband MIMO channels." Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27240.

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Wireless communication using multiple-input multiple-output (MIMO) technology enables increased spectral efficiency. The successful deployment of commercial MIMO systems requires a strong understanding of the channel conditions to achieve desired BER performance. A simple channel model that is frequently used in MIMO research assumes i.i.d. complex Gaussian distributed channel gains to describe the channel links. However, this model ignores common propagation effects present in outdoor environments. On the other hand, the wireless channel is very complex to describe using closed-form expressions. The objective of the work presented in this thesis is to parameterise the wireless channel using metrics and use these to predict the bit-error rate (BER) performance for different simulated MIMO techniques. The data measurements were obtained in Ottawa, Ontario at approximately 2 GHz, using the CRC MIMO testbed. Communications systems employing spatial multiplexing or space-time block coding (STBC) are mainly designed for operation under ideal channel characteristics. We consider (1) Vertical-Bell Labs Layered Space-Time (V-BLAST) architecture and (2) a QPSK-based quasi-orthogonal STBC. The measured data exhibit different location-specific characteristics. In some regions, the spatial correlation is low resulting in high diversity and high available mutual information. In others, spatial correlation is higher. Of all the metrics considered, we have identified six that provide useful information to describe the wireless channel. These include effective channel rank, correlation and diversity. The impact of signal power has also been investigated. It has been found that the performance spatial multiplexing is dominantly dependent on the smallest eigenvalue of the spatial correlation matrix. It is not, however, as useful in predicting the performance of STBC. Spatial correlations appear to improve the BER performance of STBC by improving the effective average SNR. It is important to note this trend is opposite to that found in spatial multiplexing. The largest eigenvalue also appears to have an impact on STBC performance. Also, it is shown that mutual information is sufficient enough to describe channel behaviour. These metrics give insight into the dominant propagation mechanisms in the environment and demonstrate the effectiveness of this kind of measurements in characterising the behaviour of the mobile radio channel.

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Do, Minh-Tien. "Ultra-narrowband wireless sensor networks modeling and optimization." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0065/document.

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Cette thèse a pour but de modéliser les réseaux de capteurs sans fil à faible débit (WSN) basés sur la technique ultra bande étroite. Ce réseau a déjà été déployée par la société SIGFOX et a déjà démontré sa très grande efficacité pour les applications pour l’Internet des objets (IoTs) grâce à sa capacité de communication point à point efficace en terme de puissance consommée, et de sa connectivité de longue portée. Cette étude donne quelques aperçus sur le passage à l’échelle de la technique de l’UNB pour un réseau multipoint à point pour une liaison montante. L’accès au canal spécifique qui est basé sur l’accès multiple par répartition aléatoire de fréquence et de temps (R-FTDMA) est introduit et analysé. En outre, l’impact de l’interférence due à l’absence de stratégie d’ordonnancement à la couche MAC est étudié et modélisé. Notre modèle simplifié nous permet non seulement de décrire la puissance d’interférence agrégée, mais aussi d’évaluer les performances du système d’un tel réseau en matière de taux d’erreur et de probabilité de coupure. De même, la géométrie stochastique est utilisée pour modéliser la distribution spatiale des noeuds afin d’étendre le modèle simplifié dans le canal réaliste où les dégradations de canal sont prises en compte. De plus, le mécanisme de retransmission est considéré pour ce réseau. Cette étude permet de d’identifier le nombre optimal de retransmissions. Le réseau peut être configuré avec un paramètre global unique. Et enfin, cette thèse met en évidence le fait que le réseau de l’UNB Random-FTDMA est très pertinent dans un réseau réaliste, en particulier pour les applications à faible débit, car il allége le coût élevé du réseau, le coût de la synchronisation globale, mais sans perte de performance
This thesis aims at modeling the low-throughput wireless sensor networks (WSNs) based on ultra-narrow-band technology. Such wireless network is already been deployed by Sigfox company and has proved to be ultra-efficient for the Internet of things (IoTs) applications thanks to its ability of point-to-point communication in terms of power efficiency and long range connectivity. In particular, this thesis gives some insights on the scalability of UNB technology for a multi-point-to-point network in an uplink scenario. The multiple access schemes based on random time and frequency selection are introduced and analyzed. Furthermore, the interference impact due to the lack of scheduling strategy at the MAC layer is studied and modeled. Our simplified model using rectangular function allows us not only to describe the aggregate interference power but also evaluate the system performance of such network in terms of the bit-error-rate and outage probability. Besides, the geometry stochastic is used for spatial node distribution in order to extend the simplified model in the realistic channel communication where the channel impairments are taken into account. Besides, the retransmission mechanism is considered for such network. This study argues an optimal number of retransmission. The network can be configured with a unique global parameter. Last but not least, this thesis highlights the fact that the UNB network using Random-FTDMA schemes is very relevant in a realistic network, especially for low-throughput applications, because it bypasses the high network cost, the cost of global synchronization but without loss of performance

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Zilevu, Kojo Sitsofe. "A Nonlinear Technique for Bandwidth Improvement in Narrowband Antennas." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/76984.

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Electrically small, low profile antennas have become the new frontier in wireless communication research. With the pressure to miniaturize wireless communication devices, engineers are turning to small low profile antennas as a way to reduce their antennas and hence their devices. Ideally, one would also like to at least maintain antenna bandwidth and efficiency while reducing size. However, in theory, antenna performance degrades when it is miniaturized—impedance bandwidth decreases with the reduction in antenna size. This thesis investigates the possibility of increasing the input impedance bandwidth without enlarging the volume of the antenna. This thesis attempts to break the fundamental tradeoff between antenna size and bandwidth by loading it with a nonlinear element. First, a brief summary of antenna background definitions is presented. Next, the analytical framework of the thesis is presented using a model of a narrowband antenna. A literature review of various narrowband electrically small antennas is studied, including the pros and cons of the Inverted-F antenna (IFA), Inverted-L antenna (ILA), and the Planar Inverted-F antenna (PIFA).Next, the analysis and the methodology leading to results are discussed and simulated results are presented. Simulated results show that the PIFA is able to achieve a higher bandwidth with a loaded nonlinear element. However, it is difficult to sustain the efficiency of the antenna due to harmonics generated by nonlinearity in the antenna. Results indicate that an increase in nonlinearity tends to generate harmonics which leads to losses in the antenna.
Master of Science

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Omid, Abedi. "Analog and Digital Approaches to UWB Narrowband Interference Cancellation." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23366.

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Ultra wide band (UWB) is an extremely promising wireless technology for researchers and industrials. One of the most interesting is its high data rate and fading robustness due to selective frequency fading. However, beside such advantages, UWB system performance is highly affected by existing narrowband interference (NBI), undesired UWB signals and tone/multi-tone noises. For this reason, research about NBI cancellation is still a challenge to improve the system performance vs. receiver complexity, power consumption, linearity, etc. In this work, the two major receiver sections, i.e., analog (radiofrequency or RF) and digital (digital signal processing or DSP), were considered and new techniques proposed to reduce circuit complexity and power consumption, while improving signal parameters. In the RF section, different multiband UWB low-noise amplifier key design parameters were investigated like circuit configuration, input matching and desired/undesired frequency band filtering, highlighting the most suitable filtering package for efficient UWB NBI cancellation. In the DSP section, due to pulse transmitter signals, different issues like modulation type and level, pulse variety, shape and color noise/tone noise assumptions, were addressed for efficient NBI cancelation. A comparison was performed in terms of bit-error rate, signal-to-interference ratio, signal-to-noise ratio, and channel capacity to highlight the most suitable parameters for efficient DSP design. The optimum number of filters that allows the filter bandwidth to be reduced by following the required low sampling rate and thus improving the system bit error rate was also investigated.

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Panthula, Sandeep. "Narrowband interference cancellation for wireless communications with channel distortion /." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1426092.

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Edwards, Stephen G. "Active narrowband disturbance rejection on an ultra quiet platform." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1999. http://handle.dtic.mil/100.2/ADA370575.

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Dissertation (Ph.D. in Aeronautical and Astronautical Engineenirg) Naval Postgraduate School, Sepember 1999.
"September 1999". Dissertation supervisor(s}: Brij Agrawal, Roberto Cristi. Includes bibliographical references (p. 223-231). Also available online.

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Epps, Julien Electrical Engineering &amp Telecommunications Faculty of Engineering UNSW. "Wideband extension of narrowband speech for enhancement and coding." Awarded by:University of New South Wales. Electrical Engineering and Telecommunications, 2000. http://handle.unsw.edu.au/1959.4/17234.

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Most existing telephone networks transmit narrowband coded speech which has been bandlimited to 4 kHz. Compared with normal speech, this speech has a muffled quality and reduced intelligibility, which is particularly noticeable in sounds such as /s/, /f/ and /sh/. Speech which has been bandlimited to 8 kHz is often coded for this reason, but this requires an increase in the bit rate. Wideband enhancement is a scheme that adds a synthesized highband signal to narrowband speech to produce a higher quality wideband speech signal. The synthesized highband signal is based entirely on information contained in the narrowband speech, and is thus achieved at zero increase in the bit rate from a coding perspective. Wideband enhancement can function as a post-processor to any narrowband telephone receiver, or alternatively it can be combined with any narrowband speech coder to produce a very low bit rate wideband speech coder. Applications include higher quality mobile, teleconferencing, and internet telephony. This thesis examines in detail each component of the wideband enhancement scheme: highband excitation synthesis, highband envelope estimation, and narrowband-highband envelope continuity. Objective and subjective test measures are formulated to assess existing and new methods for all components, and the likely limitations to the performance of wideband enhancement are also investigated. A new method for highband excitation synthesis is proposed that uses a combination of sinusoidal transform coding-based excitation and random excitation. Several new techniques for highband spectral envelope estimation are also developed. The performance of these techniques is shown to be approaching the limit likely to be achieved. Subjective tests demonstrate that wideband speech synthesized using these techniques has higher quality than the input narrowband speech. Finally, a new paradigm for very low bit rate wideband speech coding is presented in which the quality of the wideband enhancement scheme is improved further by allocating a very small bitstream for highband envelope and gain coding. Thus, this thesis demonstrates that wideband speech can be communicated at or near the bit rate of a narrowband speech coder.

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Hansmann, Esti Mari. "An investigation of coupling mechanisms in narrowband microwave filters." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/2496.

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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2008.
The design of an aperture-coupled coaxial diplexer for R-band, is presented. To improve the ease of tuning, a tuning procedure for the diplexer with the aid of a MATLAB application with graphical user interface, is developed. Final experimental results show good agreement between the circuit model and the physical structure. Final measurements of the diplexer structure achieved 18.83 dB and 21.52 dB return loss in the lower and upper frequency band respectively and insertion loss of 0.58 dB and 0.61 dB was measured for the two frequency bands. Isolation were measured as 74 dB at 2.01 GHz and 84 dB at 2.17 GHz The accuracy of two techniques for determining coupling coefficients in coaxial and waveguide resonators are investigated. One method is the Eigenmode Method for determining the coupling coefficients in a physical resonator and the other the circuit model representation, utilising inverters to represent the coupling between resonators. Results showed that marked differences occur when using the three different inverter configurations to enable filter dimensioning for a given coupling coefficient. Four waveguide filters, utilising posts and irises respectively, are designed using dimensions obtained from the three inverter configurations as well as the Eigenmode method for a certain coupling coefficient.

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Donnelly, Peter Gerard. "Adaptive parametric modelling of narrowband signals for sonar applications." Thesis, University of Ulster, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357582.

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Kelleci, Burak. "Multi-band OFDM UWB receiver with narrowband interference suppression." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2498.

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Abdolvand, Reza. "Thin-film piezoelectric-on-substrate resonators and narrowband filters." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/28113.

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Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008.
Committee Chair: Farrokh Ayazi; Committee Member: James D. Meindl; Committee Member: John D. Cressler; Committee Member: Nazanin Bassiri-Gharb; Committee Member: Oliver Brand.

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Succo, Kelli Fredrickson. "Acoustic Intensity of Narrowband Signals in Free-Field Environments." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/7092.

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The phase and amplitude gradient estimator (PAGE) method has proven successful in improving the accuracy of measured energy quantities over the p-p method, which has traditionally been used, in several applications. One advantage of the PAGE method is the use of phase unwrapping, which allows for increased measurement bandwidth above the spatial Nyquist frequency. However, phase unwrapping works best for broadband sources in free-field environments with high coherence. Narrowband sources often do not have coherent phase information over a sufficient bandwidth for a phase unwrapping algorithm to unwrap properly. In fact, phase unwrapping processing can cause significant error when there is no coherent signal near and above the spatial Nyquist frequency. However, for signals at any frequencies up to the spatial Nyquist frequency, the PAGE method provides correct intensity measurements regardless of the bandwidth of the signal. This is an improved bandwidth over the traditional method. For narrowband sources above the spatial Nyquist frequency, additional information is necessary for the PAGE method to provide accurate acoustic intensity. With sufficient bandwidth and a coherence of at least 0.1 at the spatial Nyquist frequency, a relatively narrowband source above the spatial Nyquist frequency can be unwrapped accurately. One way of using extra information, called the extrapolated PAGE method, uses the phase of a tone below the spatial Nyquist frequency and an assumption of a propagating field, and therefore linear phase, to extrapolate the phase above the spatial Nyquist frequency. Also, within certain angular and amplitude constraints, low-level broadband noise can be added to the field near a source emitting a narrowband signal above the spatial Nyquist frequency. The low-level additive broadband noise can then provide enough phase information for the phase to be correct at the frequencies of the narrowband signal. All of these methods have been shown to work in a free-field environment.

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Kenny, Sean P. (Sean Patrick) 1961. "Optimal rejection of nonstationary narrowband disturbances for flexible systems." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/8101.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2002.
Includes bibliographical references (p. 181-185).
Optimal performance and optimal allocation of resources, such as pointing accuracy and onboard fuel utilization, are of primary concern in the design and operation of precision pointing spacecraft. Ironically, internal spacecraft instruments and reaction control actuators often act as sources of narrowband disturbances and impede the optimal performance of these precision systems. The fundamental objective of this work is the development of an active control methodology capable of rejecting disturbances with narrowband nonstationary spectral distributions with particular focus on spacecraft reaction wheel induced disturbances. A closed-form symbolically parameterized optimal feed-forward disturbance rejection methodology for flexible systems has been developed. The methodology combines disturbance modeling for narrowband disturbances together with quasi-stationary optimal control to yield a parameterized feed-forward control architecture. In the case of the reaction wheel disturbance rejection problem, the symbolic optimal control gains are parameterized in terms of wheel spin rate, enabling continuous and analytically exact gain adjustments as a function of the measurable scheduling parameter. The methodology was shown to be compatible with loop-shaping control design methods such as frequency-weighted optimal control. This quasi-stationary disturbance rejection methodology has been generalized and applied to the nonstationary reaction wheel imbalance problem. The nonstationary formulation involves expanding the reaction wheel's angular states in terms of a general series representation. Bessel functions and their properties are employed to define an equivalent finite-dimensional quasi-stationary disturbance signal.
(cont.) The effectiveness of the methodology has been experimentally demonstrated on a highly compliant system with non-collocated sensors and actuators. Experimental results show peak performance yielding nearly a 40 dB improvement over conventional broadband control with improved performance across a wide range of frequencies.
by Sean P. Kenny.
Ph.D.

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Costa, Vinícius Lagrota Rodrigues da. "A prototype of a narrowband hybrid PLC/Wireless transceiver." Universidade Federal de Juiz de Fora (UFJF), 2017. https://repositorio.ufjf.br/jspui/handle/ufjf/6494.

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Esta dissertação descreve o protótipo de um transceptor banda estreita (narrowband - NB) hybrid power line communication (PLC)/Wireless (NB hybrid PLC/Wireless), o qual utiliza a rede de energia elétrica e o ar, em paralelo, para transmissão de dados, visando aplicações de redes inteligentes (smart grid - SG) e Internet das Coisas (Internet of Things - IoT). Nesse protótipo é introduzida uma versão aprimorada e adaptada do padrão IEEE 1901.2, contemplando a subcamada de controle de acesso ao meio (medium access control - MAC) e da camada física (physical - PHY) para transmissão de dados por ambos os meios de comunicação. O aprimoramento é baseado no uso da transformada de Hilbert para a recuperação da informação em quadratura em ambos os canais, possibilitando a estimação do desvio de frequência entre os clocks do transmissor e do receptor. Uma das adaptações no padrão IEEE 1901.2 é a introdução do protocolo de roteamento, o qual possibilita o transceptor a se comunicar com nós a dois ou mais saltos de distância entre eles. A outra adaptação é a implementação de uma técnica de correção de pacotes com erro a nível de camada de enlace, a qual combina os pacotes com erros recebidos pelas interfaces PLC e/ou wireless e corrige-os, dentro de uma certa capacidade. Importante ressaltar que o transceptor NB hybrid PLC/Wireless é capaz de interoperar com o transceptor NB PLC baseados no padrão IEEE 1901.2. O protótipo do transceptor NB hybrid PLC/Wireless é implementado usando um dispositivo field-programmable gate array (FPGA) usando uma linguagem descritiva de hardware (hardware description language - HDL), buscando-se a economia de recursos de hardware. Os resultados numéricos discutem o tempo necessário para execução da técnica de correção de pacotes com erros, levando em consideração as restrições de tempo do padrão IEEE 1901.2. Além disso, uma análise de taxa de dados na camada PHY mostra que a implementação está de acordo com o padrão IEEE 1901.2 e pode perfeitamente satisfazer as necessidades de aplicações para SG e IoT. Ademais, a análise do uso de recursos de hardware e do consumo de energia mostram que o protótipo do transceptor NB hybrid PLC/Wireless demanda menos que uma vez e meia os recursos de hardware e o consumo de energia do protótipo do transceptor NB PLC.
This thesis focuses on a prototype of the so-called narrowband (NB) hybrid power line communication (PLC)/Wireless transceiver, which jointly uses power line and wireless channels, in parallel, for data communication related to smart grid (SG) and Internet of Things (IoT) applications. To build the prototype, it is introduced an enhanced and adapted version of the IEEE 1901.2 Standard to implement the medium access control (MAC) sublayer and the physical (PHY) layer to transmit data through both channels. The enhancement is based on the use of the Hilbert transform to recover the quadrature information from both channels, enabling to estimate the frequency deviation between the transmitter and receiver’s clocks. One adaptation in the IEEE 1901.2 Standard is the introduction of a routing protocol, which enables the transceivers to communication with nodes two hops or farther from each other. The other adaptation is the implementation of a packet error correction technique at the link layer level, which combines packets with errors received from PLC and wireless media and correct them, under certain constraint. Moreover, relevant is the fact that the NB hybrid PLC/Wireless transceiver is compatible with the NB PLC transceiver based on the IEEE 1901.2 Standard. The NB hybrid PLC/Wireless transceiver prototype is implemented in a field-programmable gate array (FPGA) device and details about the implementation, using a hardware description language (HDL), are provided, highlighting the pursuit of hardware resource savings. Numeric results discuss the time analysis of the packet error correction technique, calculating its maximum capacity of correction taking into account the IEEE 1901.2 Standard time constraints. Furthermore, a PHY layer data-rate analysis shows that the implementation agree with the IEEE 1901.2 Standard and can perfectly satisfy the needs of SG and IoT applications. In addition, the hardware resource usage and power consumption analysis show that the NB hybrid PLC/Wireless transceiver prototype demands less than one and a half times the hardware resource usage and power consumption of the NB PLC transceiver prototype.

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Guo, Chen. "A study of detection models for narrowband reproducible noise." Thesis, Boston University, 2014. https://hdl.handle.net/2144/21162.

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Thesis (M.Sc.Eng.) PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.
Binaural hearing studies focus on how binaural processing improves the extraction of information from one source in the presence of competing sources. The most extensively studied condition is the detection of an out-of-phase tonal signal in an interaurally identical, Gaussian masking noise, called the N0Spi condition. Recently, attention turned to the dependence of detection performance on individual waveforms in the context of random noise waveforms from trial to trial. This thesis addresses this dependence, as measured in experiments (Isabelle 1991, 1995) that estimated probabilities of detection (Pd) and false alarm (Pf) for each of 30, narrowband-noise waveforms in the N0Spi condition. In previous work, models were shown to describe average performance and much of the variation over Pd, but the variation of Pf across noise samples was not explained. The current study explores two approaches to understanding the variation of Pd and Pf with noise waveform. First, a metric based on Shannon entropy is evaluated with the entropy computed from a combination of Pd and Pf. Second, internal noise in the form of temporal jitter is incorporated into existing interaural differences models. Results show that the correlation of the variation of interaural differences with the entropy is slightly stronger than that correlation with Pd alone. Models based on variations in the interaural differences with temporal jitter included are neither better nor worse than those without temporal jitter. Overall, these results suggest that the variation with Pf as captured by the entropy can be explained by interaural difference models.
2031-01-01

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36

Lin, Chun-Ching. "Demodulation of Narrowband Radio Frequency Signals by Aliasing Sampling." PDXScholar, 1996. https://pdxscholar.library.pdx.edu/open_access_etds/5286.

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The objective of this thesis is to study the demodulation of narrowband radio frequency signals by aliasing sampling in order to reduce the sampling rate. The spectrum can be recreated at the lower frequency position by aliasing sampling. However, if the sampling rate is deviated from the desired one, error will occur. The sensitivity to the frequency error of aliasing sampling is studied. One main reason of the deviation of the sampling rate is the frequency drifting of the local oscillator. Being able to compensate the oscillator drifting errors inexpensively, automatic frequency control (AFC) loops are important at receivers. Two major digital AFC algorithms are studied. One is the Phase method AFC, and the other is the Magnitude method AFC. Study indicates that both methods perform almost equally well. One adaptive AFC algorithm is also proposed. The scheme of the adaptive AFC algorithm is to use Upper-bound and Lower-bound techniques to squeeze the frequency errors. It is shown that the adaptive AFC algorithm can achieve up to 20 dB average signal-to-noise power ratio over the Magnitude method AFC under a noisy environment.

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Novotný, Jaromír. "Univerzální komunikační zařízení využívající technologie LoRaWAN a Narrowband IoT." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-400910.

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This Master thesis is focused on the design and consequential realization of the Multi-RAT communication device. The theoretical part describes a comparison of two promising communication LPWA (Low Power Wide Area) technologies that are available to use in the Czech Republic. These technologies are NB-IoT (NarrowBand-Internet of Things) and LoRaWAN (Long Range Wide Area Network). The practical part contains a description used components, their consequential fitting and testing of designed printed circuit board of the device. The thesis also describes the implementation of software and realized measurement. Technical documentation of a device can be found in the appendix of this thesis.

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Yaskoff, Nicholas Thomas. "ANALYSIS, SIMULATION, AND EXPERIMENTS FOR ADDITIVE NARROWBAND COMMUNICATION SYSTEMS." Ohio University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1180713870.

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Xu, Jinglin. "Self-healing Narrowband MEMS Filter Design for RF Receivers." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/884.

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As the radio frequency (RF) spectrum is becoming increasingly occupied, receivers are designed to resist out-of-band interferers. Due to lack of on-chip high quality factor (high-Q) filters, conventional receivers pursue frequency translation using mixers and VCOs, which inevitably increases power consumption and area and degrades noise and linearity. The piezoelectric AlN contour mode resonator filter, with its high-Q, low insertion loss and compatibiliy with CMOS integration, has emerged as a viable option for a high performance channel selection filter as the first stage of a direct sampling receiver. However, maintaining frequency precision for any high Q filter is challenging in the presence of both random and systematic process variations. To address this, the extended statistical element selection (ESES) method is applied to compensate for the frequency variations using a combinatorial redundancy scheme. This research explores the feasibility, advantages, implementation, and testing of a heterogeneously integrated switchable AlN filter system that can minimize parasitics and “self-heal” to increase yield and to realize uniform loading. In addition, several design techniques are proposed to implement the selfhealing filter to a 1 GHz receiver frontend, including breaking LNAs into sub-LNAs to select sub-filters and using current summing to uniformly combine signal outputs. To control parasitics, 3-D integration is used to limit the interconnection lengths between the CMOS switches and the AlN resonators.

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Bouchech, Hamdi. "Selection of optimal narrowband multispectral images for face recognition." Thesis, Dijon, 2015. http://www.theses.fr/2015DIJOS030/document.

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Les performances des systèmes de reconnaissance des visages en utilisant des images RGB baissent rapidement quand ils sont appliqués dans des conditions d’illumination extrêmes. L’utilisation des images multispectrales représente une alternative prometteuse pour résoudre ce problème. Dans cette thèse on s’intéresse à l’utilisation des images multispectrales visibles pour la reconnaissance des visages humains. Les images multispectrales visibles sont des images capturées à des longueurs d’ondes différentes du spectre visible (band spectral) qui s’étend de 480nm à 720nm. Ces images représentent des caractéristiques qui favorisent la reconnaissance des visages humains dans des conditions particulières comme la présence d’excès d’illumination incidente sur le visage photographié. Notre travail consiste à exploiter ces caractéristiques sur des stages différentes: optimiser le choix du nombre de bandes spectrales à utiliser, optimiser les longueurs d’ondes choisies, optimiser les techniques de fusion des informations extraites à partir des différentes bandes spectrales pour avoir plus d’informations utiles et moins d’informations bruits. Plusieurs nouvelles approches ont été proposées dans le cadre de ce travail avec des résultats encourageants en termes de performances. Ces approches ont exploité plusieurs outils mathématiques pour resoudre les différents problèmes rencontrés, en particulier la formulation de la sélection des bandes spectrales optimales sous formes de problèmes d’optimisation où nous avons utilisé le « basis pursuit algorithm » pour déterminer un vecteur de poids sparse pour représenter l’importance des différentes bandes. Dans d’autres problèmes d’optimisation, nous avons attribué à chaque bande un classifieur faible, puis combiné les classifieurs faibles avec dif- férents poids associés selon l’importance. La méthode Adaboost a été utilisée pour trouver la combinaison optimale. D’autres techniques ont introduites d’une manière originale la dé- composition multilinéaire des images de visage pour formuler une sorte de base de données caractérisant les bandes spectrales. Cette base de données a été utilisée avec les nouvelles images, ou image test, pour déterminer les bandes les plus robustes contre une variation importante d’illumination. Le travail présenté dans le cadre de cette thèse est une petite contribution à la reconnaissance des visages en utilisant des images multispectrales, qui est une approche d’actualité, mais qui nécessite encore plus de développement afin de maximiser ses performances
Face recognition systems based on ’conventional’ images have reached a significant level of maturity with some practical successes. However, their performance may degrade under poor and/or changing illumination. Multispectral imagery represents a viable alternative to conventional imaging in the search for a robust and practical identification system. Multi- spectral imaging (MI) can be defined as a ’collection of several monochrome images of the same scene, each of them taken with additional receptors sensitive to other frequencies of the visible light or to frequencies beyond the visible light like the infrared region of electro- magnetic continuum. Each image is referred to as a band or a channel. However, one weakness of MI is that they may significantly increase the system processing time because of the huge quantity of data to be mined; in some cases, hundreds of MI are taken for each subject. In this thesis, we propose to solve this problem by developing new approaches to select the set of best visible spectral bands for face matching. For this purpose, the problem of best spectral bands selection is formulated as an optimization problem where spectral bands are constrained to maximize the recognition accuracy under challenging imaging conditions. We reduce the redundancy of both spectral and spatial information without losing valuable details needed for the object recognition, discrimination and classification. We have investigated several mathematic and optimization tools widely used in the field of image processing. One of the approaches we have proposed formulated the problem of best spectral bands selection as a pursuit problem where weights of importance were affected to each spectral band and the vector of all weights was constrained to be sparse with most of its elements are zeros. In another work, we have assigned to each spectral band a linear discriminant analysis (LDA) based weak classifier. Then, all weak classifiers were boosted together using an Adaboost process. From this later, each weak classifier obtained a weight that characterizes its importance and hence the quality of the corresponding spectral band. Several other techniques were also used for best spectral bands selection including but not limited to mixture of Gaussian based modeling, multilinear sparse decomposition, image quality factors, local descriptors like SURF and HGPP, likelihood ratio and so on. These different techniques enabled to build systems for best spectral bands selection that are either static with the same bands are selected for all the subjects or dynamic with each new subject get its own set of best bands. This latter category, dynamic systems, is an original component of our work that, to the best of our knowledge, has not been proposed before; all existing systems are only static. Finally, the proposed algorithms were compared to state-of-the-art algorithms developed for face recognition purposes in general and specifically for best spectral bands selection

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Verdin, Dan. "Synchronisation in sampled receivers for narrowband digital modulation schemes." Thesis, University of York, 1995. http://etheses.whiterose.ac.uk/10839/.

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ZHOU, XIN. "SPATIO-TEMPORAL JOINT MUSIC ALGORITHM FOR NARROWBAND AND WIDEBAND DIRECTION OF ARRIVAL ESTIMATION." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1069850811.

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Huo, Lu [Verfasser]. "Attribute-based Speech Quality Assessment : – Narrowband and Wideband / Lu Huo." Aachen : Shaker, 2015. http://d-nb.info/1074087593/34.

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Cross, Lee W. "Design of Microwave Front-End Narrowband Filter and Limiter Components." Thesis, The University of Toledo, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3588122.

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This dissertation proposes three novel bandpass filter structures to protect systems exposed to damaging levels of electromagnetic (EM) radiation from intentional and unintentional high-power microwave (HPM) sources. This is of interest because many commercial microwave communications and sensor systems are unprotected from high power levels. Novel technologies to harden front-end components must maintain existing system performance and cost. The proposed concepts all use low-cost printed circuit board (PCB) fabrication to create compact solutions that support high integration.

The first proposed filter achieves size reduction of 46% using a technology that is suitable for low-loss, narrowband filters that can handle high power levels. This is accomplished by reducing a substrate-integrated waveguide (SIW) loaded evanescent-mode bandpass filter to a half-mode SIW (HMSIW) structure. Demonstrated third-order SIW and HMSIW filters have 1.7 GHz center frequency and 0.2 GHz bandwidth. Simulation and measurements of the filters utilizing combline resonators prove the underlying principles.

The second proposed device combines a traditional microstrip bent hairpin filter with encapsulated gas plasma elements to create a filter-limiter: a novel narrowband filter with integral HPM limiter behavior. An equivalent circuit model is presented for the ac coupled plasma-shell components used in this dissertation, and parameter values were extracted from measured results and EM simulation. The theory of operation of the proposed filter-limiter was experimentally validated and key predictions were demonstrated including two modes of operation in the on state: a constant output power mode and constant attenuation mode at high power. A third-order filter-limiter with center frequency of 870 MHz was demonstrated. It operates passively from incident microwave energy, and can be primed with an external voltage source to reduce both limiter turn-on threshold power and output power variation during limiting. Limiter functionality has minimal impact on filter size, weight, performance, and cost.

The third proposed device demonstrates a large-area, light-weight plasma device that interacts with propagating X-band (8-12 GHz) microwave energy. The structure acts as a switchable EM aperture that can be integrated into a radome structure that shields enclosed antenna(s) from incident energy. Active elements are plasma-shells that are electrically excited by frequency selective surfaces (FSS) that are transparent to the frequency band of interest. The result is equivalent to large-area free-space plasma confined in a discrete layer. A novel structure was designed with the aid of full-wave simulation and was fabricated as a 76.2 mm square array. Transmission performance was tested across different drive voltages and incidence angles. Switchable attenuation of 7 dB was measured across the passband when driven with 1400 V_pp at 1 MHz. Plasma electron density was estimated to be 3.6 × 10¹² cm^-3 from theory and full-wave simulation. The proposed structure has potential for use on mobile platforms.

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Gunduz, Aysegul. "Compression and Transmission of Facial Images Over Very Narrowband Channels." NCSU, 2003. http://www.lib.ncsu.edu/theses/available/etd-03312003-001013/.

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Law enforcement officers on mobile duty are often confronted with ID authentication of subjects, requiring the transmission of a driver?s license picture over wireless channels with very narrow bandwidths. To access mug shots in a reliable and timely manner, real time compression and decompression methods with high compression ratios are required at the server database and at the mobile client unit. This thesis presents a methodology, which minimizes the size of the data sent over the channel by locally storing common features of the human face in the client computers. Pre-processing of server database images, such as facial feature extraction, are used to extract these common facial features, and are obtained via topological methods, in particular, via ravine extraction. The implemented file transfer protocols are based on basic TCP/IP client-server models and make use of socket programming. Experimental results show a 4x improvement in transfer time over typically saturated channels.

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Ladas, Charalampos V. "Transport layer protocol optimisation for narrowband mobile and wireless links." Thesis, University of Sheffield, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412724.

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Mockford, Stephen. "Narrowband characterisation of UHF mobile radio channels in rural areas." Thesis, University of Liverpool, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279747.

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Butt, Gulraiz. "Narrowband characterisation of high elevation angle land mobile satellite channel." Thesis, University of Surrey, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314857.

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Long, John R. (John Robert) Carleton University Dissertation Engineering Electronics. "A Narrowband radio receiver front-end for portable communications applications." Ottawa, 1996.

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Hadaschik, Niels. "Analysis of wideband OFDM in the presence of narrowband interference." Aachen Shaker, 2008. http://d-nb.info/99315736X/04.

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Dissertations / Theses on the topic 'Narrowband'

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