The paper discusses a new design of a current–mode reconnection–less reconfigurable fractional–order (FO) low–pass filter of various orders. The filtering structure is based on a 4th–order leap–frog topology using operational transconductance amplifiers as basic building blocks. The resulting order of the filter is given by the setting of current gains (allowing the reconnection–less reconfiguration) alongside with the values of the fractional–order capacitors realized by the RC ladder networks. For this purpose, RC ladder networks of orders 0.3, 0.4, 0.5, 0.6 and 0.7 have been designed. The fractional–order form of the filter contains from one up to four FO capacitors (remaining capacitors (if there are any) are of integer–order) allowing to obtain low–pass functions of order of 3 + α, 2 + α, 1 + α, 2 + α + β, 1 + α + β, α + β, 1 + α + β + γ, α + β + γ and α + β + γ + δ. The proposed filter offers a wide variety of possible order combinations with an increasing degree of freedom as the number of fractional–order capacitors within the structure increases. The proposal is supported by the PSpice simulations of magnitude and phase characteristics, pole frequency adjustment and stability analysis. Moreover, the experimental measurements of the implemented filter were carried out and compared with the simulation results. The possibility of the electronic control of the fractional order is also discussed and presented.

本文讨论了一种新的电流模式无连接可重构分数阶（FO）低通滤波器的新设计。滤波结构基于四阶越级跳跃拓扑，使用运算跨导放大器作为基本构建块。滤波器的最终阶数由电流增益的设置（允许重新连接而无需重新配置）以及由RC梯形网络实现的分数阶电容器的值给出。为此，已经设计了0.3、0.4、0.5、0.6和0.7级的RC梯形网络。滤波器的分数阶形式包含一个至四个FO电容器（其余电容器（如果有）为整数阶），从而可以获得3 + α，2 +  α阶的低通函数 ，1 +  α，2 +  α  +  β，1 +  α  +  β，α  +  β， 1 +  α  +  β  +  γ，α  +  β  +  γ和α  +  β  +  γ  +  δ。随着结构内分数阶电容器数量的增加，所提出的滤波器提供了多种可能的阶次组合，并具有更大的自由度。PSpice的幅度和相位特性仿真，极点频率调整和稳定性分析为该建议提供了支持。此外，对所实现的滤波器进行了实验测量，并与仿真结果进行了比较。还讨论并介绍了分数阶电子控制的可能性。