We try to design a notch filter on 400Hz by ADA4077-4 but it can't work. Would you kind to give some recommendation ?Thanks.
Good day! Thank you for your interest in using ADI Parts. Upon simulating your circuit on Multisim, I found no problem on the response of ADA4077-4 being used in your circuit. Some questions, what are your supply voltages? What is your input voltage on your simulation? What are the problems you encountered? What is your expected output? Can you supply me some screenshots and/or pictures of your simulation? What will your application be? Upon answering these questions, I could help you further in your application.
A notch filter is a filter wherein it will attenuate frequency on a given frequency range. On your circuit it will attenuate frequency from 300Hz to 500Hz having 400Hz as its central frequency. For your problem, it won’t be able to attenuate your input signal of 1kHz because it is out of the range 300Hz to 500Hz. If you want to attenuate or filter signal from 400Hz to 1000Hz, you may look into low pass filter, which may be able to filter frequencies higher than 400Hz. Or you may also increase the bandwidth of your circuit in order to capture the 1kHz.