Band-Reject (Notch) Active Filter
It may be obtained by the parallel connection of a high-pass section with a low-pass section. The cut-off frequency of the high-pass section must be greater than that of the low-pass section.
The outputs of HP and LP sections are fed to an adder whose output voltage V0 will have the notch filter characteristics.
Applications of Notch Filters
Notch filter is used where unwanted frequencies are to be attenuated while permitting the other signal frequencies to pass through.