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» Circuit synthesis using admittance network modification and GA in MATLAB

Many methods of automatic synthesis of electronic circuits were published. Some of them implement modern optimization methods such as genetic algorithms or genetic programming [1-3]. Transformation from desired transfer function to active - RC circuit structure using mathematical modifications of admittance matrix was presented in [4]. The goal of these methods is to develop a tool for automatic synthesis of electronic circuits where engineer without deeper knowledge of principles of electronic circuits should be able to design analog structure which realizes desired transfer function. Another area of using these methods is searching for new circuit structures based on new active blocks. Method presented in this paper is suitable for synthesis of all possible circuit structure[...] więcej»
w zeszycie ELEKTRONIKA - KONSTRUKCJE, TECHNOLOGIE, ZASTOSOWANIA 2009/12

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» Multifunctional voltage adjustable CM biquad using commercially available current conveyors

ROMAN SOTNER

JOSEF SLEZAK

TOMAS DOSTAL

Well-known structures of ARC filters based on voltage opamps (OA) are used generally in low-frequency applications. Better solution for higher frequencies is to replace the voltage opamps with active blocks in current mode, which have attractive features like higher speed of signal processing, operation at higher frequencies (several MHz) and implementation in full integration form using modern bipolar, CMOS, BiCMOS and GaAs technologies. Some types of active blocks allow electronic controlling of their specific parameter, what gives us possibility of electronic adjusting of some parameters of constructed circuit. Development in signal processing has shown that current mode (CM) approach is better than the voltage mode (VM) in terms of wider bandwidth, higher speed, lower DC v[...] więcej»
w zeszycie ELEKTRONIKA - KONSTRUKCJE, TECHNOLOGIE, ZASTOSOWANIA 2009/12

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» On the derivation of Piecewise-Linear Chaotic Oscillators using Simulated Annealing Method and Hspice

Josef SLEZAK

Jiri PETRZELA

Roman SOTNER

The several novel structures of the chaotic oscillators with piecewise-linear vector field are derived and verified. For the synthesis of the linear part of the circuit the so-called simulated annealing method is utilized. For the rapid calculation of the fitness function the circuit simulator Hspice is used. Starting with the given mathematical model, namely the eigenvalues for each state space region, the final circuits consist of parallel connection of idealized nonlinear resistor and higher-order linear admittance. Streszczenie. Przedstawiono kilka nowych chaotycznych generatorów w częściowo liniowym wektorem pola. Do syntezy części liniowej obwodu wykorzystano metodę symulowanego wyżarzania. Do szybkich obliczeń funkcji sprawności użyto symulatora Hspice. Startując od modelu matematycznego wartości własne dla każdego regionu składają się z równoległych połączeń idealizowanych rezystorów nieliniowych i admitancji wyższego rzędu. (Częściowo liniowy chaotyczny generator wykorzystujący symulowane wyżarzanie i Hspice). Keywords: analog oscillator, chaotic motion, nonlinear dynamics, simulated annealing, global optimization. Słowa kluczowe: generator, symulowane wyżarzanie.. Introduction To date, the plenty methods for synthesis of the linear circuits already exist. The most of them are based on the matrix-pencil approach. Unfortunately it is hard to use them in the case of the large complex networks with potentially negative circuit elements. In such situations computer-aided design is preferred. The fundamental question which is faced here which method should be used to solve the particular problem. The main idea is to transfer the problem from circuit synthesis to the optimization task. Doing this, there is no need to know the analytical expression of the fitness function since some sort of stochastic optimization can be used. There are two basic algorithms and many different modifications, namely genetic algorithm (GA) and partic[...] więcej»
w zeszycie PRZEGLĄD ELEKTROTECHNICZNY 2011/1

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» Multifunctional adjustable biquadratic active RC filters: design approach by modification of corresponding signal flow graphs

Roman SOTNER

Bretislav SEVCIK

Lubomir BRANCIK

Tomas DOSTAL

An useful modification of well known signal flow graph technique for the circuit synthesis is described in this paper in order to obtain the filters working in the current mode, with maximally variable parameters, namely characteristic frequency, quality factor, bandwidth and basic gain. Procedure is based on reciprocal conversion of the branch variables (VI and IV) with the adjustable conversion constants. The obtained structures are discussed in detail and then is described an example of current-mode multifunctional RC active biquadratic filter, what is today very popular analogue application. Theoretic assumptions are supported by experimental results using modern functional blocks CC II(-). Streszczenie. Opisano metodę analizy grafów przepływowych do projektowania filtrów pracujących w trybie prądowym z uwzględnieniem charakterystyki częstotliwościowej, współczynnika jakości, pasma I wzmocnienia. Procedura bazuje na odwrotnej konwersji zmiennych. Otrzymaną strukturę filtru przedyskutowano na przykładzie wielofunkcyjnego filtru RC w trybie prądowym. Analiza teoretyczna poparta jest wynikami eksperymentu. (Wielofunkcyjny nastawny aktywny filtr RC - projektowanie z wykorzystaniem grafów przepływowych) Keywords: Signal flown graphs, current-mode circuits, ARC filters, electronic adjusting, current conveyors. Słowa kluczowe: filtry aktywne, grafy przepływowe, tryb prądowy. Introduction Today there are available many functional blocks for the analogue signal processing that are better in some views than the classical operational amplifiers. We can mention for example larger bandwidth, better dynamics and linearity, lower power consumption and first of all possibilities of electronic adjusting, via typical parameter controlled in most cases by external DC voltage or current. For example there are transconductors (OTA) [1, 2], where transconductance (gm) is driven by DC bias current, many types of current conveyors (CC) [1,[...] więcej»
w zeszycie PRZEGLĄD ELEKTROTECHNICZNY 2011/2

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