Active noise control (ANC) is an active noise mitigation method that has in recent years become increasingly prevalent. The method relies on the principle of superposition, canceling unwanted noise through the addition of a second sound wave with the same amplitude but an inverted phase to the first. One of the most common applications of ANC is in hearables, particularly in wireless earbuds. Because of individual differences in ear anatomy, the requirements for an effective ANC system will vary slightly among different users. However, the static nature of most ANC systems in hearables means that they are unable to account for these anatomical differences, resulting in inconsistent noise reduction across individuals. The aim of this project is to develop an adaptive ANC system capable of accounting for individual variations in ear anatomy through the use of optimization algorithms and adaptive filters. The proposed adaptive ANC system is designed to operate as a separate layer alongside the static ANC system and is implemented in a simulated environment with the help of Python. The effectiveness of the adaptive system is evaluated relative to the static system in terms of overall sound pressure level (OASPL) as well as power spectral density (PSD) across several test participants. The results indicate that the adaptive system indeed provides a noticeable improvement over the standalone static system.

Switching-mode power converters are one of the most ubiquitous electronic devices thatare used in all fields of life - from simple home appliances to cutting-edge space technologies.Often the power converter is one of the weakest links in the equipment since it isusually directly connected to the power grid and will be affected first from voltage spikesand other irregularities. As a lot of the applications of switching-mode power convertersare mission-critical, it is important to minimize the risks of unexpected breakdowns of thedevices. The aim of this project is to find a simple and reliable way to diagnose a failingpower converter in order to make it possible to react before the failure could affect themain equipment. For that, a basis for a Discrete Time Fourier Transform based methodwas developed, which could allow to diagnose some of the most common potential failuresof equipment using simple and robust devices for measurement and analysis. This reportdetails patterns in the general time-domain shapes of the voltage load and current as wellas the high-frequency components of the voltage. In addition, it also looks at these patternsin the frequency domain and suggests a few possibilities for how a method could bedeveloped. The results of the work show the potential of the approach for further developmentof an embedded diagnostic unit that would make it possible to forecast emergingfailure of a power unit.

This thesis addresses the issue of GPS satellite spoofing using affordable hardware. The approach involves capturing I/Q-samples from GPS-signals and employing a phase interferometry algorithm for direction finding. By determining the direction of a satellite at a given time and comparing this with decoded navigation messages that reveal the satellite's actual location. This method is able to verify the authenticity of the satellite signals where a discrepancy between these locations suggests potential spoofing. Although the project's theoretical contributions are significant, the practical outcomes fell short of the initial ambitions due to various constraints encountered during the study. Nonetheless, the findings provide valuable insights into the detection of GPS spoofing, highlighting both the potential and the limitations of the proposed method within the allotted timeframe.

This thesis describes and discusses design and implementation of digital filters inembedded systems. Digital filters provide great flexibility where an interchangeablefilter is needed and real valued components are limited. Common sampling problemssuch as aliasing and reconstruction are discussed and solved using analog filters.A circuitry is constructed to interact with the embedded system according to itsspecifications. Digital filter theory is reviewed and applied in both IIR (Infinite ImpulseResponse) and FIR (Finite Impulse Response) filters. Design methods used arewindow method for the FIR filter and zero-pole placement for the IIR filter. Thefilters are implemented in c code on an embedded system named UC3-A3 AVR-boardfrom Atmel. The complete system is effectively used to filter a music piece fromunwanted interference and noise with real-time computing.

<p>The mainpart of this thesis is about the developing of a new analysis tool to be used in Zenicor Medical Systems AB ECG-system. The primary task of the system is to simplify the ECG survey for patients who suffers from different kinds of arrythmias, for example heart fibrillation. With this system is it possible for the patients to do their ECG survey by them self at home and then send the signal with their telephone or mobilphone to a server. The equipment used to do the survey is not bigger than you can have it in a pocket and this results in a bigger flexibility for the patient. A doctor can connect to the server and analys the ECG-curve and follow up the patients condition.</p>

The mainpart of this thesis is about the developing of a new analysis tool to be used in Zenicor Medical Systems AB ECG-system. The primary task of the system is to simplify the ECG survey for patients who suffers from different kinds of arrythmias, for example heart fibrillation. With this system is it possible for the patients to do their ECG survey by them self at home and then send the signal with their telephone or mobilphone to a server. The equipment used to do the survey is not bigger than you can have it in a pocket and this results in a bigger flexibility for the patient. A doctor can connect to the server and analys the ECG-curve and follow up the patients condition.

Diss. Ronneby : Tekn. högsk., 2002.

<p>In this thesis, analytical analysis and design techniques for wireless communications with diversity are studied. The impact of impairments such as correlated fading is analyzed using statistical models. Countermeasures designed to overcome, or even exploit, such effects are proposed and examined. In particular two applications are considered, satellite broadcast to vehicular terminals and communication using transmitters and receivers equipped with multiple antennas.</p><p>Mobile satellite broadcast systems offer the possibility of high data rate services with reliability and ubiquitous coverage. The design of system architectures providing such services requires complex trade-offs involving technical, economical, and regulatory aspects. A satisfactory availability can be ensured using space, terrestrial, and time diversity techniques. The amount of applied diversity affects the spectral efficiency and system performance. Also, dedicated satellite and terrestrial networks represent significant investments and regulatory limitations may further complicate system design.</p><p>The work presented in this thesis provides insights to the technical</p><p>aspects of the trade-offs above. This is done by deriving an efficient method for estimating what resources in terms of spectrum and delay are required for a broadcast service to reach a satisfactory number of end users using a well designed system. The results are based on statistical models of the mobile satellite channel for which efficient analytical design and error rate estimation methods are derived. We also provide insight to the achievable spectral efficiency using different transmitter and receiver configurations.</p><p>Multiple-element antenna communication is a promising technology for future high speed wireless infrastructures. By adding a spatial dimension, radio resources in terms of transmission power and spectrum can be used more efficiently. Much of the design and analysis work has focused on cases where the transmitter either has access to perfect channel state information or it is blind and the spatial channels are uncorrelated.</p><p>Herein, systems where the fading of the spatial channels is correlated and/or the transmitter has access to partial channel state information are considered. While maintaining perfect channel knowledge at the transmitter may prove difficult, updating parameters that change on a slower time scale could be realistic. Here we formulate analysis and design techniques based on statistical models of the multichannel propagation. Fundamental properties of the multi-element antenna channel and limitations given by information theory are investigated under an asymptotic assumption on the number of antennas on either side of the system. For example, limiting normal distributions are derived for the squared singular values of the channel matrix and the mutual information. We also propose and examine a practical scheme capable of exploiting partial channel state information.</p><p>In both applications outlined above, by using statistical models of the channel characteristics in the system design, performance can be improved. The main contribution of this thesis is the development of efficient techniques for estimating the system performance in different scenarios. Such techniques are vital to obtain insights to the impact of different impairments and how countermeasures against these should be designed.</p>

In this thesis, analytical analysis and design techniques for wireless communications with diversity are studied. The impact of impairments such as correlated fading is analyzed using statistical models. Countermeasures designed to overcome, or even exploit, such effects are proposed and examined. In particular two applications are considered, satellite broadcast to vehicular terminals and communication using transmitters and receivers equipped with multiple antennas. Mobile satellite broadcast systems offer the possibility of high data rate services with reliability and ubiquitous coverage. The design of system architectures providing such services requires complex trade-offs involving technical, economical, and regulatory aspects. A satisfactory availability can be ensured using space, terrestrial, and time diversity techniques. The amount of applied diversity affects the spectral efficiency and system performance. Also, dedicated satellite and terrestrial networks represent significant investments and regulatory limitations may further complicate system design. The work presented in this thesis provides insights to the technical aspects of the trade-offs above. This is done by deriving an efficient method for estimating what resources in terms of spectrum and delay are required for a broadcast service to reach a satisfactory number of end users using a well designed system. The results are based on statistical models of the mobile satellite channel for which efficient analytical design and error rate estimation methods are derived. We also provide insight to the achievable spectral efficiency using different transmitter and receiver configurations. Multiple-element antenna communication is a promising technology for future high speed wireless infrastructures. By adding a spatial dimension, radio resources in terms of transmission power and spectrum can be used more efficiently. Much of the design and analysis work has focused on cases where the transmitter either has access to perfect channel state information or it is blind and the spatial channels are uncorrelated. Herein, systems where the fading of the spatial channels is correlated and/or the transmitter has access to partial channel state information are considered. While maintaining perfect channel knowledge at the transmitter may prove difficult, updating parameters that change on a slower time scale could be realistic. Here we formulate analysis and design techniques based on statistical models of the multichannel propagation. Fundamental properties of the multi-element antenna channel and limitations given by information theory are investigated under an asymptotic assumption on the number of antennas on either side of the system. For example, limiting normal distributions are derived for the squared singular values of the channel matrix and the mutual information. We also propose and examine a practical scheme capable of exploiting partial channel state information. In both applications outlined above, by using statistical models of the channel characteristics in the system design, performance can be improved. The main contribution of this thesis is the development of efficient techniques for estimating the system performance in different scenarios. Such techniques are vital to obtain insights to the impact of different impairments and how countermeasures against these should be designed. / QC 20101019

<p>The main control task in many speed-controlled drives is to eliminate or reduce the load speed error caused by the load torque disturbance and reduce oscillations as quickly as possible. This thesis addresses different aspects of identification and control of such resonant elastic systems.</p><p>In most industrial applications it is not practical to measure the load speed. Instead, we advocate model based control design that optimizes load speed while using motor speed as the feedback signal. For this to be possible one needs a mechanical model of the system and we suggest finding the mechanical parameters by estimation from experimental data.</p><p>Hence a method has been developed which finds the mechanical parameters, including backlash, through a series of three dedicated experiments. At first this procedure is developed for the situation of one manipulated input, the motor torque, and one measured output, the motor speed.</p><p>For drive systems with a very large motor in comparison to the load, it becomes very difficult to estimate all mechanical parameters from motor speed measurements only. An alternative estimation method has been developed for this purpose, using an additional sensor for the shaft torque.</p><p>One more rather specific control problem is treated in the thesis, namely for drive systems with tandem coupled motors, where control structures have been developed with and without an extra sensor for shaft torque.</p>