Several new topologies of the HAPF system are proposed which come from the study on impedance-frequency characteristic of the passive filter of HAPF system.

文章从滤波器阻抗频率特性的角度出发，提出了几种具有广阔应用前景的新型混合有源滤波器拓扑。

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Power lines are extremely hostile places for data signals, with high levels of electronic noise and an obstacle course of transformers, surge arrestors and splices that create a huge impedance to the free flow of high-frequency signals.

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