This master’s thesis is about replace voltage feedback operation amplifiers (VFOA) by current operational amplifiers (COA), current conveyors and current followers (CF). In introduction are mentioned word or two about operational amplifiers and their basic circuit such as invert and non-invert amplifier and there are described formulas for calculation gain. In another chapter is described COA, his properties and advantages compared to VFOA. Next there are described basic circuits of current conveyors. Follows chapter where is described replace VFOA by COA and conversion between them. In another part is at first deal with models of COA and CF in simulating program and then replace VFOA by COA. There are some simple circuits for example precision rectifiers and function generators and their simulations before and after replace VFOA by COA. In full-wave rectifier with current conveyors is made detailed simulation with some input voltages and frequencies. In last chapter is detailed described multi-mode rectifier with current follower. There is table witch described all modes of rectifier. For example voltage mode, current mode and mixed mode with half- or full-wave rectifier. There are simulations for all modes. Primarily are made detailed simulations voltage and current mode. In another part of this chapter is made measurement voltage and current mode. There are measured functions as half- and full-wave rectifier. There are described parameters of rectifier from measured values. In the end are these values compared with values from simulations.

Nanoscale p-channel transistors under negative gate bias at an elevated temperature show threshold voltage degradation after a short period of stress time. In addition, nanoscale (45 nm) n-channel transistors using high-k (HfO2) dielectrics to reduce gate leakage power for advanced microprocessors exhibit fast transient charge trapping effect leading to threshold voltage instability and mobility reduction. A simulation methodology to quantify the circuit level degradation subjected to negative bias temperature instability (NBTI) and fast transient charge trapping effect has been developed in this thesis work. Different current mirror and two-stage operation amplifier structures are studied to evaluate the impact of NBTI on CMOS analog circuit performances for nanoscale applications. Fundamental digital circuit such as an eleven-stage ring oscillator has also been evaluated to examine the fast transient charge transient effect of HfO2 high-k transistors on the propagation delay of ring oscillator performance. The preliminary results show that the negative bias temperature instability reduces the bandwidth of CMOS operating amplifiers, but increases the amplifier's voltage gain at mid-frequency range. The transient charge trapping effect increases the propagation delay of ring oscillator. The evaluation methodology developed in this thesis could be extended to study other CMOS device and circuit reliability issues subjected to electrical and temperature stresses.

This work is aimed on design of a device for testing of fire detectors and various components of fire detection system, communicating with the fire panel over a fire bus or a loop. The device generates voltages, supplying the detectors, as well as communicating over the bus generating communication waveforms and performing detection of responses measuring voltage and current on the connection. The loop signal is processed by the developed unit and data or result sent to a PC utilizing USB or RS232 connection. All the parts of the equipment are galvanically isolated to the loop circuit.

This Master`s thesis concern with problematic of connection analog sensors with voltage output 0-10V to a ethernet communication network. Due to a quick evolution and an application ethernet nets to industry and building technologies is possible to use this solution for connection remote diagnostics and setting of existing analog sensors without bus communication interfaces on instrumentation level of field bus networks. The converter is based on Rabbit module, which can be used like webserver for setting, calibration and data recording. For purpose of wide converter use the data output will be purvey on ethernet interface by Modbus TCP and on asynchronous serial interface RS232. First part of thesis is aimed on description of existing solutions and introduction with principles of linearization and calibration of A/D converters. Description of communication standard Modbus TCP widely used in industry applications. Second part of thesis describes design a realization of project. Here is described equipment block diagram with detail description of each block and devices used. In the part of implementation is description of device firmware with program function description and control. Last part is engage with module function verification supported with plantz of measurements and tests. The thesis is ended with evaluation results, knowledge and detections found out in development of project.

This thesis deals with the synthesis and optimization of frequency analogue filters with modern active elements usable for higher frequencies. The thesis is divided into three parts, the first part deals with the problematic concerning Leap-Frog combined ARC structure. Due to a difficult design, this method is not described in a detail and used in practice, although it shows e.g. low sensitivity. Firstly, a complete analysis of individual filters was made (for and T endings) and consequently these findings were used during implementation of this method to NAF program. Finally, samples of real filters were realized (for verification of functioning and correct design). Another very interesting topic concerning filters is usage of coupled band-pass for small bandwidth, where it is necessary to solve the problems concerning ratio of building elements values, but also price, quality, size of coils, sensitivity, Q factors, coefficients etc. That is why in practice a coil is very often substituted with other equivalent lossy and lossless blocks which create ARC filters structure. The design and the possibility of usage of lossy grounded elements were described here (such as synthetic inductors, frequency dependent negative resistor). Some parts of the design are individual computer sensitivity analysis, setting of usage and quality comparison of individual lossy grounded blocks. Besides, a program for these elements was created, it is useful for a quick design and depiction of transfer characteristics. The third part deals with the usage of tuning universal filters consisting three or more operational amplifiers, which secures its universality and possibility to create different kinds of transfer characteristic. In practice, Akerberg - Mossberg and Kerwin - Huelsman - Newcomb are the most used types of filters. These were also compared with less common universal filters. In the end, the possibility of digital tuning of universal filter with the help of digital potentiometers for filters of 10th order and frequency around 1 MHz was shown.