Lets assume I have a signal that exists in time and it has an unit impulse at t=5, I only want to filter out that portion of the signal. So I plan to design a passband filter to filter the signal out at t=5. This is where I get confused, my passband filter exist in frequency so how is that going to filter the signal out? I'm not sure whats the range for example 50 hz to 100 hz. If I want to have the filter exist at t = 4 through t=6 is it simply going to be 1/4 hz to 1/6 hz? Assuming I get the range right, will my output after getting passed through the filter just be a unit impulse? Will it still exist at t=5? This isn't homework I'm just trying to understand so I can start designing.