一款平顶特性窄带滤波器的设计

Design of Flat-roofed Narrow Band Pass Filter

为满足地球物理勘探中频域测试的需求,利用数值计算的方法,计算并得出了两级级联的有源带通滤波器在临界偏调时各级中心频率f0与Q值的关系;据此设计并制作了具有平顶特性的窄带通滤波器。实测结果表明其特性与理论计算曲线一致。此外,还对电路的选择性、灵敏度、平顶宽度以及等效噪声带宽等参数作了进一步讨论。建议利用该电路设计成50Hz工频陷波器。

In order to fulfill the need of frequency domain test in geophysical exploration, with numerical method, the relationship can be obtained between all-levels central frequency and Q value when the two stage cascade filter is critical for offset, according to which, a flattened narrow-belt band pass filter is designed. And the test result indicates that its characteristics are consistent with theoretical calculating curve. Besides, the selectivity, sensitivity, the width of flat-top and Low-Noise bandwidth of the circuit are discussed. And the suggestion of designing a notch filter of 50Hz power frequency by using this circuit comes as a conclusion.