Active high-pass filter and active low-pass filter

摘要

2.1.A known active high-pass filter and active low-pass filter exhibits an active bandpass filter (120), to which a first high-pass filter (160) and a first low-pass filter (130), respectively, is allocated. The known active high-pass filter and the known active low-pass filter are to be developed further in such a manner that these filters produce only a slight phase rotation in the passband. 2.2.This object is achieved in that a second high-pass filter (150) and a second low-pass filter (140), respectively, is provided between the input (10) to the active high-pass filter or to the active low-pass filter and an input for setting the operating point (15) of the active bandpass filter (12). 2.3.A preferred application for an active low-pass filter according to the invention is a PLL circuit which has a particularly short settling time by using the active low-pass filter. 3.The drawing shows a circuit diagram of an active low-pass filter according to the invention. IMAGE