Οι συνεχώς αυξανόμενες ανάγκες της σημερινής αγοράς για φορητές ηλεκτρονικές συσκευές και τηλεπικοινωνιακά συστήματα χαμηλής τάσης τροφοδοσίας και χαμηλής κατανάλωσης ισχύος, καθιστά απαραίτητη τη σχεδίαση ενεργών βαθμίδων οι οποίες θα είναι ικανές να λειτουργήσουν σε ένα περιβάλλον όπου μία απλή τάση τροφοδοσίας μικρότερη ή ίση με 1.5V είναι διαθέσιμη. Έτσι, στην εργασία αυτή θα γίνει μια μελέτη διαφορετικών ενεργών βαθμίδων που δύνανται να λειτουργήσουν στο περιβάλλον αυτό, συγκρίνοντας τις δυνατότητες τους. Η μελέτη αυτή αφορά στις ενεργές βαθμίδες CCII και CFOA, καθώς και σε παραλλαγές τους που αφορούν στη λειτουργία των βαθμίδων αυτών με διαφορική τάση εισόδου (DVCCII και DVCFOA).Απώτερος σκοπός της σύγκρισης των βαθμίδων αυτών, αποτελεί η εφαρμογή τους στη σχεδίαση και υλοποίηση μιγαδικών φίλτρων. Έτσι, έπειτα από μία πλήρη περιγραφή των μιγαδικών φίλτρων ώστε να κατανοηθεί η λειτουργία τους, αλλά και των προβλημάτων που εισάγουν την ανάγκη χρήσης τέτοιων φίλτρων, θα μελετηθεί η χρησιμότητα καθεμιάς από τις παραπάνω ενεργές βαθμίδες στη σχεδίαση μιγαδικών φίλτρων ανώτερης τάξης, τα οποία πληρούν τις προδιαγραφές της εκάστοτε τεχνολογίας. Συγκεκριμένα θα γίνει η σχεδίαση και υλοποίηση ενός μιγαδικού φίλτρου 12ης τάξης ικανού να λειτουργεί (κατ’ επιλογή) τόσο για ένα κανάλι μετάδοσης μέσω του πρωτοκόλλου Bluetooth, όσο και για ένα κανάλι μετάδοσης μέσω του πρωτοκόλλου ZigBee.Τελικό βήμα της εργασίας, αποτελεί η φυσική σχεδίαση του κυκλώματος που θα προκύψει, ώστε να επαληθευτεί η ορθή λειτουργία του σε ένα περισσότερο ρεαλιστικό περιβάλλον. / The ever-increasing needs of today's market for portable electronic devices and telecommunication systems of low voltage and low power consumption, necessitates the design of active building blocks that are likely to operate in an environment where a single supply voltage less than or equal to 1.5V is available. Thus, this work will be a study of different active building blocks that may operate in this environment, comparing their abilities. The study refers to active building blocks CCII and CFOA, as well as variations related to their operation involving differential input voltage (DVCCII and DVCFOA). The ultimate goal of comparing these blocks is their application in the design and implementation of complex filters. Thus, after a full description of complex filters to understand their functioning and the problems that introduce the need to use such filters, the usefulness of each of these blocks will be studied in the design of higher-order complex filters, which meet the specifications of each technology. In particular a 12th order complex filter able to function (optional) for both a transmission channel over Bluetooth Protocol, and a transmission channel over ZigBee Protocol, will be designed and implemented. Final step of the work is the physical layout of the circuit, so as to verify the proper functioning in a more realistic environment.

Tato disertační práce pojednává o návrhu nových funkčních bloků použitelných v oblasti zpracování analogového signálu. Jde o obvody v proudové módu, které mohou ve vhodné konfiguraci pracovat v proudovém i v napěťovém módu. To umožnílo získat velmi nadějné výsledky v soustavách s nízkým napájecím napětím. Mnohostrannost těchto obvodů nalezne uplatnění v mnoha aplikacích. Zesilovač s proudovou zpětnou vazbou byl zavolen jako hlavní stavební blok pro detailní zkoumání funkce obvodů s RC operační sítí. Tato disertační práce pojednává o studiu, syntéze a návrhových aspektech realizace nových imitančních funkcí, jmenovitě induktivních a superkapacitních, proudových a napěťových konvejorech, kmitočtových filtrech s velkou jakostí, integrátorech a diferenciátorech, fázovacích členech s neminimální fází a napětím řízených oscilátorech. Disertační práce se detailně zabývá těmito novými bloky, které jsou popsány teoreticky a vyhodnoceny na základě simulací vlastností.

This thesis deals with RC oscillators applicable in higher frequency ranges with the use of modern active elements. For individual function blocks (conveyor, current feedback amplifier, operational transconductance amplifier, voltage feedback amplifier) suitable models are suggested for the circuit simulator PSpice covering their characteristics on various levels, from an ideal one up to the full description of parasitic effects. On the basis of the study of recommended literature and company documentation various oscillator connections of the ranks 2 and 3 are suggested. By analysis through computer (PSpice, SNAP) the fulfilment of oscillation conditions, onset of oscillations were verified and by means of suitable simulations the effects of the impact on the parasitic characteristics of active elements was examined. Finally there are two oscillator connections stated and verified by simulations with the possibility of electronic retuning.

The diploma thesis deals about design of the ARC multifunctional filters using modern functional blocks. These active blocks are for example voltage feedback operational amplifiers (OAs), operational transconductance amplifiers (OTAs), current conveyors (CCIIs) or current mode analog multipliers, current feedback amplifiers (CFAs), integrated circuits with switched capacitors building blocks (SCs) and digital potentiometers. The filters are studied with ideal circuit models and models of third level (3) based on voltage controlled voltage sources, voltage controlled current sources etc. (analog behavioral modelling). The professional macromodels are used for example LT 1364 (Linear Technology), EL 2045 (Intersil), LT 1228 (Linear Technology), LM 13700 (National Semiconductor), EL 2082 (Intersil), AD 844 (Analog Devices) and others. The circuits of the designed filters are simulated in PSpice (OrCAD), parasite effects and effects of the real parts are studied. Tuning and electronic adjusting parameters these filters are discussed and controlled by simulation in PSpice. Properties some simulated circuits are compare with experimental results. In conclusion individual filters are discussed and compared their properties. The constructional details of the some filters are presented at the end of this work.

This dissertation thesis deals with design of new functional blocks usable in area of analogue signal processing, focusing on sensor signal processing. Versatility of these circuits will find applications in programmable analogue array structures that will be possible to control and configure via a digital signal. Hereby build-up array would be fully a reconfigurable digital control system for sensor signal processing and usable for a wide range of different sensors. It offers possibility to build-up a control code for each specific sensor system, with which it would be possible to achieve optimal results of the entire system and consequently place the system on a chip. The presented programmable array is designed from configurable analogue blocks. The current feedback circuits, which in a suitable configuration can operate in voltage or current mode, are used here. This allows to achieve very good results in the systems with very low power supply, which is closely associated with mobility and autonomous behavioral (that are very important and observed parameters today) of the entire sensor-based framework. The work deals in detail with particular blocks, which are described theoretically and evaluated for using in the programmable analogue array. Design of the structure of programmable analogue array as well the use of these circuits in the part of whole system (that will be realized on a chip) are presented at the end of this thesis.

The implementation of portable electroencephalography (EEG) systems has been known to be complex. During ambulation, the integrity of recorded EEG signals is often impaired by motion artifacts and the time and effort required to set up the system is excessive. The use of single-channel EEG systems with dry, active electrodes (AEs) for signal acquisition is a topic of current interest. AEs are electrodes which have integrated bioamplifier circuitry and are known to be less susceptible to motion artifacts and environmental interference. In this report, the design of an AE preamplifier for the purpose of improving single-channel EEG recordings is presented. Initially, a thorough literature review was performed, exploring the available knowledge and state-of-the-art technology. Thereafter, the design specifications were set and the appropriate topology and circuit design techniques were selected to maximize the amplifier’s performance. Ultimately, three different preamplifier topologies were designed and their performance compared with one another as well as with established medical device standards and state-of-the-art AEs. The results of one preamplifier showed comparable performance with state-of-the-art AEs. Therefore, this topology was selected for a deep analysis and physical layout design. The layout of the selected preamplifier was designed and its parasitics extracted. The post layout performance of the design proved to be comparable to the schematic level performance, with a CMRR of 153dB, IRNV of 0.89µVRMS and an electrode offset tolerance of 450mV. The preamplifier design presented in this report has proven to be comparable with state-of-the-art AE preamplifiers and demonstrates potential for the advancement of AE performance in single-channel EEG systems. / Implementeringen av bärbara elektroencefalografisystem (EEG) har varit känd för att vara komplex. Vid rörelse påverkas ofta reliabiliteten av de inspelade EEGsignalerna av rörelseartefakter samt av att tiden och det arbete som krävs för att ställa in systemet blir överdrivet lång. Användandet av singelkanals EEG-system, med torra aktiva elektroder (AE) under inspelningen, är ett aktuellt ämne. En AE är en elektrod som har en integrerad bioförstärkarkrets och är känd för att vara både mindre mottaglig för rörelseartefakter och för störning från omgivningen. I denna rapport presenteras utformningen av en AE-förförstärkare för singelkanals EEGinspelningar. Inledningsvis utfördes en grundlig litteraturöversikt där den rådande kunskapen och toppmoderna tekniken undersöktes. Därefter bestämdes designspecifikationerna, lämpliga topologier samt kretsdesigntekniker, för att maximera förstärkarens prestanda. Slutligen konstruerades tre olika förstärkares topologier och deras prestanda jämfördes med varandra liksom med etablerade medicin tekniska standarder och toppmoderna AE. Resultaten av en förförstärkare visade sig ha jämförbar prestanda med toppmoderna AE. Därför valdes denna topologi ut för en djupanalys och för fysisk layoutkonstruktion. Layouten för den valda förförstärkaren utformades och dess parasiter extraherades. Utformningen av postlayouten visade sig vara jämförbar med prestanda på en schematisk nivå, med en CMRR på 153dB, IRNV på 0.89µVRMS och en elektrodoffsettolerans på 450mV. Förförstärkarens design som presenteras i denna rapport har visat sig vara jämförbar med toppmoderna AE-förförstärkare och visar potential till framsteg för AEprestanda i singelkanals EEG-system