Ing. Jiří Náhlík, Ph.D.

A class of computer-aided optimization methods based on Differential Evolution (DE), Particle Swarm Optimization (PSO) and Nelder Mead algorithms applied to a switched-capacitor (SC) filter circuit design are investigated. Comparisons of these algorithms applied to a 4th order biquadratic two-channel filter bank CMOS design on 0. 35 μm technology are made. The frequency responses of the biquadratic filters must match ideal responses in a finite number of iterations with a limited number of ”particles”. The original and derived methods are evaluated on the base of their convergence progress and their reliability over different starting populations. An optimal design approach based on combining algorithms is derived as a more suitable and more reliable method for SC circuit optimization.

The paper investigates the performance of the Nelder-Mead (NM) and Differential Evolution (DE) hybrid algorithm applied to switched capacitor (SC) filter optimization. The performance is investigated on a design of four biquadratic filters and the results are compared to the original algorithm performances and other hybrid algorithms performances

Switching analog circuits design places high demands on both the designed circuitry and the designer's experience. Optimization algorithms can help to debug the circuit both for the real part parasitic effects and for production process changes. It is necessary to take into account the computing time during the optimization and effectivity in solving of given problem. This paper deals with the effectivity of optimization methods applied to the design of SC circuits.

Implementation of the switched capacitor circuits (SC) puts high demands on the used components, which real properties affect the final circuit operation. Therefore the resulting circuit needs to be optimized for nonidealities effects. This paper deals with the performance of the Differential Evolution algorithm (DE) and Particle Swarm Optimization algorithm (PSO). In order to improve the algorithm performance the three combinations of DE and PSO are proposed. Algorithm performances are compared on the optimization of four biquadratic SC filters for fourth order two-channel filter bank.

The paper investigates the performance of the Differential Evolution (DE) and Particle Swarm Optimization (PSO) algorithm for SC filter Optimization. In order to improve their performance the three algorithm based on their combination are proposed. The performance is investigated on the design of switched capacitor biquadratic filters and the resulting performance and limitations are discussed.

This paper deals with the design and optimization of biquadratic switched capacitor filters for 4th order quadrature-mirror filter banks allowing for real switch effects (e.g. on-state resistance, charge injection...) and the folded cascode OpAmp designed in 0.35 um CMOS technology. The filter is designed as a cascade of two biquads and each filter is separately optimized using the Differential Evolution Algorithm to obtain the required transfer function with deviation of less than ±0.1 dB from the designed transfer function. The filters process a baseband signals (0 - 8 kHz) using a clock frequency of 16 kHz. The resulting capacitor values are presented.

The description of physical reality can be rarely done without modeling and computer processing, especially in case of the description of the complex processes or large set of simpler processes. In order to quantify the processes, it is necessary to describe it mathematically. It concerns both an individual process and the systems including these processes.

The aim of this paper is to describe the implementation of a two-channel filter bank (FB) using the switched capacitor (SC) technique considering real properties of operational amplifiers (OpAmps). The design procedure is presented and key recommendations for the implementation are given. The implementation procedure describes the design of two-channel filter bank using an IIR Cauer filter, conversion of IIR into the SC filters and the final implementation of the SC filters. The whole design and an SC circuit implementation is performed by a PraCAn package in Maple. To verify the whole filter bank, resulting real property circuit structures are completely simulated by WinSpice and ELDO simulators. The results confirm that perfect reconstruction conditions can be almost accepted for the filter bank implemented by the SC circuits. The phase response of the SC filter bank is not strictly linear due to the IIR filters. However, the final ripple of a magnitude frequency response in the passband is almost constant, app. 0.5 dB for a real circuit analysis.

The aim of this paper is to describe the implementation of a two-channel filter bank (FB) using the switched capacitor (SC) technique. The implementation of two-channel filter bank using an IIR Cauer filter, conversion of IIR into the SC filters and the final implementation of the SC filters is described. The whole filter bank was realized on a printed board and the magnitude frequency response was measured for different timing of clock signals. Resulting magnitude frequency response is given. Measured responses are compared with simulated ones.

Switched capacitor technique is often used in the construction of on chip filters. These filters usualy operate with clock frequency significantly higher than the highest frequency of the processed signal. This paper describes the implementation of two-channel switched capacitors filter bank which processes signals up to half of clock frequency of 16 kHz. Filter bank has been implemented on the PCB and the resulting measured frequency responses were compared to simulated responses.

Switched capacitor technique is very often used for filters on chip. Analysis of these circuits are more complicated in comparison with circuits working in continuous time domain. It can be done by using simulation. The AC analysis of such circuits can be performed by the analysis in the time domain and then frequency response is obtained by using Discrete Fourier Transformation. By this method two-channel filter bank has been simulated in the WinSpice program. The filter bank operates with switching frequency equal to 16 kHz or 8 kHz respectively. In the simulation were considered real property of the circuit parts, so that their effect on circuit operation can be shown. According to the simulation results the filter bank was subsequently adapted.

The aim of this paper is to describe method to obtain transfer function of the switched capacitor filter bank by the simulation in the WinSpice program. The method is based on transient analysis of bank followed by Fourier transformation of computed time response. In simulation nonideal parameters of bank parts are taking to account. The obtained results are discussed.