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Laboratory device with analog computational unit AD538
Hruboš, Zdeněk ; Slezák, Josef (referee) ; Petržela, Jiří (advisor)
An analog multiplier are circuits, that are realized multiplication of two analog signals. They can be made by suitable connection (according to function) discreet parts. Nowadays there are integrated circuits in advance function, whose internal structure is made by complex of circuits with operating ampfliers and other circuits. These circuits have a very high accuracy of arithmetic operation which is mostly better than 1%. The analog multiplier are used in situation, when we need realize multiplication, division, exponentation, square root extraction and logarithmic calculation of analog signals. In the next are used in circuits for multiplication of frequency, shifting of frequency, amplitude modulation, detection phase angel of two signals with the same frequency, etc. The AD538 is a monolithic real-time computational circuit that provides precision analog multiplication, division and exponentiation. The combination of low input and output offset voltages and excellent linearity results in accurate computation over an unusually wide input dynamic range.
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Techniques of time-domain analysis of interconnects.
Lábsky, Balázs ; Petržela, Jiří (referee) ; Brančík, Lubomír (advisor)
This work deals with techniques of time-domain analysis of interconnects. After a studying crucial issue of time-domain analysis of interconnects methods of modeling and simulation simple interconnects in electrotechnics are described. For transient effect analysis two elementary methods can be used: the state variable method and the FDTD (Finite - Difference Time - Domain) method. The FDTD method can be used to solve partial differential equations in time domain, for instance equations of transmission lines. The method is very effective and delivers satisfactory results in case of linear and non-linear lines with a single “live” conductor. The method can be easily programmed in Matlab.
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Band Gap - accurate voltage reference
Bubla, Jiří ; Petržela, Jiří (referee) ; Kolka, Zdeněk (advisor)
This diploma thesis is specialized on a design of a high accuracy voltage reference Bandgap. A very low temperature coefficient and output voltage approx. 1,205V are the main features of this circuit. The paper contains a derivation of the Bandgap principle, examples of realizations of the circuits and methods of compensation temperature dependence and manufacture process, design of Brokaw and Gilbert reference, design of a testchip and measurement results.
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Electronically controlled active 2-nd order filter
Ševčík, Břetislav ; Petržela, Jiří (referee) ; Šotner, Roman (advisor)
The diploma thesis deals with the modern design of the control circuits for digital potentiometers and their application in analog systems. The concept of the digital control is demonstrated on the electronically controlled active 2-nd order filter and programmable oscillator. The proposed design of the active filter describes a programmable active 2-nd order filter Sallen-Key. In this circuit it is possible independently programme cut-off frequency, Q factor and type of approximation with very good accuracy. The circuits of the designed filter and designed oscillator are simulated in PSpice (OrCAD), parasite effects and effects of the real parts are studied. Properties simulated circuits are compare with experimental results. These results appreciate quality and efficiency of the digitally controlled potentiometers in dependence on variable input circuit parameters. Integral part of this project is author’s universal control program called Digipot and comunications interface for many types of digital potentiometers with I2C, SPI or Up/Down interface. It is possible to use this device for many applications. The constructional details of the filter are presented at the end of this work. The software equipment is availability on enclosed CD.
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Laboratory device focused on the switched capacitor circuits
Urban, Lukáš ; Šotner, Roman (referee) ; Petržela, Jiří (advisor)
This Master`s thesis is focused on through acquaintance of principles of the function circuits with switched capaticors and posibility of their application mainly in frequency filters or signal generators. The origin of the switched capacitor circuits is mentioned at the beginning of the work. There are references to the first scientific work and scientists who have dealt with this issue. Maxwell`s idea: lossy element (resistor) replace with lossless element (switched capacitor) in electric circuit, is further described. In the next chapter of this work are listed types of switching capacitors and their use in simple RC filters and in structures of inverted or noninverted integrators and their application in more complex higher order filters. The advantages and disadvantages of SC circuits versus circuit composed of discrete components are shown. It is also listed a simple low-pass switched RC filter implemented with analogue multiplexer 4053. Using the LTC1043 integrated circuit, which structure and properties are described and analyzed in detail in the work, the 1st order aktive or pasive low and high pass filters were designed and subsequently simulated in the computer simulator OrCAD PSpice v.10. Another chapter deals with the integrated circuits higher order filters, structure and properties of the integrated filter LTC1060 are further analyzed here. Except this IC there are mentioned integrated filters commercially less available from the corporations Linear Technology and Maxim. The main objective of thesis was to propose and establish laboratory device and laboratory measurment focused on the switched capacitor circuits. The laboratory device has been designed with integrated circuits LTC1043 and LTC1060, which is demonstrated by using passive and active integrator, 2nd order band-pass and 4th order band-pass with Chebyshevovou approximation.
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Modeling of the unconventional functional blocks in Pspice
Zetík, Rostislav ; Brančík, Lubomír (referee) ; Petržela, Jiří (advisor)
This master´s thesis on theme Modeling of the unconventional functional blocks in Pspice deals with the design procedures of electronic elements models and should to help with their create. At the beginning the thesis theoretically describes how the models are created and what possibilities for modeling the program Pspice offers. There are drawn near the individual levels of model and their properties. The second main part of thesis shows practically step by step the design procedures of models of the operational amplifier, current and voltage conveyors, OTA, CDTA, immittance inverter and converter and logarithmic amplifier. There are created the models up to 4.th level, the ideal, resistive, frequency dependent and nonlinear. The basic transmission properties, input and output impedance are modeled this way. The created models with sufficient accuracy correspond to the parameters of the commercial elements. This thesis such shows the possibilities of the program for finding of values for model components like stepping or Optimizer tool.
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Age effect modeling of the unipolar transistor
Soukal, Pavel ; Kolka, Zdeněk (referee) ; Petržela, Jiří (advisor)
According to non-stopable progress in wireless communications, it is desirable to integrate the RF front-end with the baseband building blocks of communication circuits into a one chip in the recent years. The CMOS technology advances, this is the reason why it becomes attractive for system-on-a-chip implementation, but CMOS device is getting shrink, so the channel electric field increasing and the hot carrier (HCI) effect becomes more significant. If the oxide is scaled down to less than 3 nm, then there is the possibility of soft or hard oxide breakdown (S/HBD) often takes place. As a result of the oxide trapping and interface generation is the long term performance drift and related reliability problems in devices and circuits. During the scaling and increasing chip power dissipation operating temperatures for device have also is increasing. Another reliability concern is the negative bias temperature instability (NBTI) caused by the interface traps under high temperature and negative gate voltage bias are arising while the operation temperature of devices is increasing. Parameter’s extraction is a very important part of the current electronic components modeling process, as it looking for the value of the unknown parameters in mathematical model, which represents physical behavior of given electronic component. The problem of parameter extraction is that fits electronic components mathematical model to a measured data set is an ill-posed problem and its solution is inherently difficult. This diploma thesis presents the parameter extraction, optimization methodology and verifies it on a case study of a MOSFET mathematical models (LEVEL1, LEVEL2 and LEVEL3) parameter extraction. The presented nonlinear method is based on the method of the least squares, which is solved with the aid of Levenberg- Marquardt’s algorithm.
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Multifunctional tuned active filter
Šotner, Roman ; Petržela, Jiří (referee) ; Dostál, Tomáš (advisor)
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.
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Oscillators RC for higher frequency range
Polách, Petr ; Petržela, Jiří (referee) ; Dostál, Tomáš (advisor)
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.
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Voltage and current integrators based on modern functional blocks and their application in filters
Šimůnek, Martin ; Petržela, Jiří (referee) ; Dostál, Tomáš (advisor)
The aim of this bachelor´s thesis was utilization of current integrator and voltage integrator along with construction of active filters. In this project are discribed universal filters, which were proposed on the basis of signal flow graphs. In this paper are presented five multifunctional sixth-order filters, which are used in modern functional blocks, for example operational amplifiers (OPA), transconductors (OTA) and current conveyors (CCII+,CCII-). From the mentioned operation amplifiers and the well-known capacitor are created integrators, which the multifunctional sixth-order filter is designed from based on cascade sorting. The aim of this paper is to compare particular types of suggested solutions and to verify the possibility of practical use of these filters with following simulations.
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