I'm trying to construct something like the band reject filter on the bode graph below.
I know that I could make this by using four different filters and adding them up (low pass filter + high frequency amplifier + high frequency amplifier + high frequency "reducer"). By adding them up I mean connecting them with buffers.
I read on many webpages that this could be made by just using a high pass filter and a low pass filter like this:
I don't understand how could I make this frequency shift on the high pass filter shown in red so it doesn't "subtract" frequencies below \$f_L\$. And how to translate this into an actual circuit.
Any help is appreciated!
EDIT: Sorry I don't have much knowledge on this, but I'm guessing that it could be made with something like this:
Where the first and last terms are low pass filters with cutoff frequencies of a and d respectively.
How could I make the second and third terms in a way that all are connected in series with dependent volages?