I want to block all frequencies higher than 12kHz coming from diffrent sources. The required filter should have the fastest response possible without inducing any ripple and the gain inside the bandwidth should be higher than +20dB and outside it should be less than -50dB.
My question is how should I design it to have the gain outside less than -50dB.
I'm new to non linear electronics so I don't have much experience.
I know exactly the steps to do for a Sallen Key design but it's just that this outside gain that is confusing me. Does this mean that I should use a 3rd order low pass filter with a Chebyshev 3dB type? Because if a 1st order LPF gives an amplitude of -20dB/decade this means that I need a 3rd order LPF.