Simulation is the process of computing a behavior determined by a given model of a system of interest.  Modeling is the process of creating a model that formally describes a given class of system.  Modeling and simulation can be used to quickly and cheaply study and understand new technologies.  Today, a wide range of systems are simulated using different tools.  However, converting models into simulation codes can still be difficult and time consuming. In this thesis, we study how a new modeling and simulation language called Acumen can be used to model basic physical links.  This language is aimed at bridging the gap between modeling and simulation.  We focus on basic physical links as an interesting type of system to model and simulate. We also focus on comparing Acumen to MATLAB and Simulink.  The types of links we consider include models of an RC low-pass filter, Amplitude Modulation, Frequency Modulation, Amplitude Shift Keying, Phase Shift Keying and Frequency Shift Keying systems. Each of these examples is modeled in Acumen, MATLAB and Simulink. We find that, for the most part, Acumen allows us to naturally express a wide range of modulation techniques mentioned above. When compared to MATLAB ad Simulink, we find that Acumen is simple language to understand. Acumen codes are described in a more natural way. Simplicity is the biggest advantage of Acumen.

A new method of realizing linear, time-invariant digital filters is developed and demonstrated. The result is based on the convolution integral. It is assumed that the specifications of the filter are known and from these, an appropriate analog filter is chosen. The properties of this filter are then retained by digital filter after transformation. The behaviour of lowpass, highpass bandpass and bandstop digital filters is investigated in both the frequency and time domains, for both cascade and parallel structure is superior for lowpass and bandpass digital filters, and that the cascade structure is superior for high pass and bandstop digital filters. / Thesis / Master of Engineering (ME)

To provide more information mobility, many wireless communication systems such as WCDMA and EDGE in phone systems, bluetooth and WIMAX in communication networks have been recently developed. Recent efforts have been made to build the allin- one next generation device which integrates a large number of wireless services into a single receiving path in order to raise the competitiveness of the device. Among all the receiver architectures, the high-IF receiver presents several unique properties for the next generation receiver by digitalizing the signal at the intermediate frequency around a few hundred MHz. In this architecture, the modulation/demodulation schemes, protocols, equalization, etc., are all determined in a software platform that runs in the digital signal processor (DSP) or FPGA. The specifications for most of front-end building blocks are relaxed, except the analog-to-digital converter (ADC). The requirements of large bandwidth, high operational frequency and high resolution make the design of the ADC very challenging. Solving the bottleneck associated with the high-IF receiver architecture is a major focus of many ongoing research efforts. In this work, a 6th-order bandpass continuous time sigma-delta ADC with measured 68.4dB SNDR at 10MHz bandwidth to accommodate video applications is proposed. Tuned at 200 MHz, the fs/4 architecture employs an 800 MHz clock frequency. By making use of a unique software-based calibration scheme together with the tuning properties of the bandpass filters developed under the umbrella of this project, the ADC performance is optimized automatically to fulfill all requirements for the high-IF architecture. In a separate project, other critical design issues for continuous-time sigma-delta ADCs are addressed, especially the issues related to unit current source mismatches in multi-level DACs as well as excess loop delays that may cause loop instability. The reported solutions are revisited to find more efficient architectures. The aforementioned techniques are used for the design of a 25MHz bandwidth lowpass continuous-time sigma-delta modulator with time-domain two-step 3-bit quantizer and DAC for WiMAX applications. The prototype is designed by employing a level-to-pulse-width modulation (PWM) converter followed by a single-level DAC in the feedback path to translate the typical digital codes into PWM signals with the proposed pulse arrangement. Therefore, the non-linearity issue from current source mismatch in multi-level DACs is prevented. The jitter behavior and timing mismatch issue of the proposed time-based methods are fully analyzed. The measurement results of a chip prototype achieving 67.7dB peak SNDR and 78dB SFDR in 25MHz bandwidth properly demonstrate the design concepts and effectiveness of time-based quantization and feedback. Both continuous-time sigma-delta ADCs were fabricated in mainstream CMOS 0.18um technologies, which are the most popular in today?s consumer electronics industry.

In this thesis, a highly selective broadband hybrid bandpass filter operating between 0.4-2.0 GHz with a stopband up to 7 GHz is designed and analyzed. The realization is carried out by hybrid method, which combines both lumped and distributed element filters. In this approach, two separate filters, which are lumped highpass with 0.4 GHz corner frequency and distributed stripline lowpass with 2 GHz corner frequency, are combined to get the bandpass filter that has a passband in between 0.4 to 2.0 GHz. The usage of the lumped elements for the highpass filter resulted in a great size reduction compared to distributed element approach. The design software FILPRO&trade / is used to synthesize the trial filters. More than forty filters are synthesized, and among them, the ones that have better properties are chosen for further processes. Optimization, modeling and electromagnetic simulations of the selected lumped and distributed filters are carried out on the software GENESYS&trade / . Distributed filters are also simulated using the software SONNET&trade / . After the simulations, all of the simulated filters are realized and measured, and the level of consistency with the simulations is observed. According to the results of the measurements, the filter combination that has the best combination of low insertion loss, small dimensions, high stopband attenuation and low spur levels is selected for the final bandpass filter structure and a few variants are examined to get the final structure.

Το αντικείμενο της εργασίας είναι ο υπολογισμός του καρδιακού και αναπνευστικού παλμού με επεξεργασία του σήματος που λαμβάνεται με χρήση πιεζοηλεκτρικού αισθητήρα. Ο αισθητήρας είναι τοποθετημένος στον λαιμό και ανιχνεύει ένα σήμα που περιλαμβάνει τόσο τον καρδιακό, όσο και τον αναπνευστικό ρυθμό. Η δειγματοληψία και μετατροπή του σήματος σε ψηφιακό γίνεται με χρήση του microcontroller MSP430F149 ο οποίος προγραμματίζεται κατάλληλα για το σκοπό αυτό. Το ψηφιακό αυτό σήμα επεξεργάζεται με κατωδιαβατό φίλτρο πεπερασμένης κρουστικής απόκρισης προκειμένου να αποκοπούν οι υψηλές συχνότητες και υπολογίζεται η ενέργεια του προκύπτοντος σήματος. Εν συνεχεία με χρήση του FFT, και κατάλληλων φίλτρων γίνεται ο διαχωρισμός του σήματος σε αναπνοής και καρδιακού ρυθμού. / -

In this study, a novel and systematic methodology for the design and optimization of lowpass filters (LPFs), and multiorder-bandpass filters (BPFs) are proposed. The width of the LPF signal traces consistently follow Fourier truncated series, and the thickness of the substrate as well. By studying different lengths and other physical constraints, the design meets predefined electrical requirements. Moreover, superformula is used in split ring resonators (SRRs) designs to obtain a BPF response and significant structural compactness. Non-uniform transmission lines, as well as superformula equations, are programmed in MATLAB, which is also used for analytical validations. Traces are drawn in AutoCAD. The substrate of LPF is constructed in Pro/e. Finally, the optimized layouts are imported to Ansys High Frequency Structure Simulation (HFSS) software for simulation and verification. Nonuniform LPFs are optimized over a range of 0-6 GHz with cutoff frequency 3.5 GHz. Superformula implemented multiorder-BPFs are optimized with cutoff frequency of 1.1 GHz.

Fordonsindustrin är inne i ett skifte, där förbränningsmotorer (ICE) bör-jar fasas ut och det satsas mer på eldrift med hjälp av batterier (BEV).  I detta arbete, som efterfrågades av Volvo Cars, utvecklades en matema-tisk modell som uppskattar den lägsta temperaturen i en elbils högspän-ningsbatteri. Modellen delades initialt upp i två delar, där den ena delen utgick från hur omgivningstemperaturen samt fordonets hastighet på-verkar eventuell värmeövergång mellan batteri och omgivning. Den andra delen utgick från hur batteriets kylsystem påverkar batteriets temperatur, där kylsystemets temperatur och flöde var de styrande fak-torerna. De styrande variablerna filtrerades med lågpassfilter där olika tidskonstanter användes. Den del som för varje tillfälle visade lägst tem-peratur var gällande. Modellen togs fram med hjälp av mätdata från testkörningar i kallt klimat där testbilens batteri var preparerad med ett antal externa temperatur sensorer, och de preparerade sensorerna an-sågs visa batteriets verkliga temperatur. Tidiga resultat visade att mo-dellen för omgivningstemperatur och hastighet visade relativt bra vär-den men saknade inflytande från kylsystemets dynamik medan mo-dellen för kylsystemet fungerade mindre bra i de flesta fall. Modellen modifierades därför till att ha hastighet och omgivningstemperatur som basfunktion och kylsystemets påverkan adderades. Resultatet visade att den senare modellen hanterade systemets dynamik bättre än tidigare modell. I framtida studier bör batteriets termiska massa samt dess egen-uppvärmning tas i beaktning. / The automotive industry is shifting from internal combustion engines (ICE) cars to battery electric vehicles (BEV). In this work, requested by Volvo Cars, a mathematical model was developed that estimates the lowest temperature of an electric car's high-voltage battery. The model was initially divided into two parts, where one part was based on how the ambient temperature and the vehicle's speed affect any heat transfer between battery and surroundings. While the second part was based on how the battery's cooling system affects the battery temperature, where the cooling system temperature and flow were the controlling factors. The controlling variables were filtered with low-pass filters where dif-ferent time constants were used. The part that showed the lowest tem-perature for each occasion was valid. The model was developed using measurement data from test runs in cold climates where the test car's battery was prepared with more temperature sensors than are in a pro-duction battery and the prepared sensors were considered to show the battery's actual temperature. Early results showed that the ambient tem-perature and speed model showed relatively good values but lacked in-fluence from the cooling system, while the model for the cooling system worked less well in most cases. The model was therefore modified to have speed and ambient temperature as the base function and the cool-ing system's impact was added. The results showed that the latter model handled the dynamics of the system better than the previous model. In future studies, the thermal mass of the battery and its self-heating should be considered.

The aim of the study was focused on problem of electrograms recording from alive tissue. Study of electrograms recording was extended with noise analysis and its elimination. Elimination of noise and disturption was made in program Matlab; lowpass filtration and wavelet transformation was used. Application for electrograms analysis was developed in latter part of this work.

The aim of the study was focused on problem of electrograms recording with using voltage sensitive dyes. Study of electrograms recording was extended with thema of optical detectors suitable for measurement and noise analysis. Elimination of noise and disturption was made in program Matlab; lowpass filtration and wavelet transformation was used. Application for electrograms analysis was developed in latter part of this work.

The thesis deals with the microstrip filter design using defected ground structure (DGS). The difference between standard asymmetric microstrip technique and DGS is in using the structures etched in the microwave substrate ground plane. The DGS resonant characteristics are then used in filter design. The thesis consists of three factual parts. The first one (chapter 4) introduces the use of the DGS resonators in the lowpass filter design. It involves experimental analysis of one type of the lowpass filter. The second part (chapter 5) deals with a novel microstrip lowpass filter design method using DGS. The proposed method is verified by simulations and several samples are realized and measured. Finally, the third part (chapters 7 and 8) deals with the bandpass filter design using specific defected ground structure as a resonator. The resonators are used in a coupled resonator structure. Filters of various orders and resonator configurations are designed and simulated. A combination of the DGS resonators and half-wavelength microstrip resonators is introduced as well. Selected samples are realized and measurement results are compared with simulations.